Tag Archives: coding

1834: The First Cyberattack

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2018/05/1834_the_first_.html

Tom Standage has a great story of the first cyberattack against a telegraph network.

The Blanc brothers traded government bonds at the exchange in the city of Bordeaux, where information about market movements took several days to arrive from Paris by mail coach. Accordingly, traders who could get the information more quickly could make money by anticipating these movements. Some tried using messengers and carrier pigeons, but the Blanc brothers found a way to use the telegraph line instead. They bribed the telegraph operator in the city of Tours to introduce deliberate errors into routine government messages being sent over the network.

The telegraph’s encoding system included a “backspace” symbol that instructed the transcriber to ignore the previous character. The addition of a spurious character indicating the direction of the previous day’s market movement, followed by a backspace, meant the text of the message being sent was unaffected when it was written out for delivery at the end of the line. But this extra character could be seen by another accomplice: a former telegraph operator who observed the telegraph tower outside Bordeaux with a telescope, and then passed on the news to the Blancs. The scam was only uncovered in 1836, when the crooked operator in Tours fell ill and revealed all to a friend, who he hoped would take his place. The Blanc brothers were put on trial, though they could not be convicted because there was no law against misuse of data networks. But the Blancs’ pioneering misuse of the French network qualifies as the world’s first cyber-attack.

Join us at the Education Summit at PyCon UK 2018

Post Syndicated from Ben Nuttall original https://www.raspberrypi.org/blog/pycon-uk-2018/

PyCon UK 2018 will take place on Saturday 15 September to Wednesday 19 September in the splendid Cardiff City Hall, just a few miles from the Sony Technology Centre where the vast majority of Raspberry Pis is made. We’re pleased to announce that we’re curating this year’s Education Summit at the conference, where we’ll offer opportunities for young people to learn programming skills, and for educators to undertake professional development!

PyCon UK Education Summit logo

PyCon UK 2018 is your chance to be welcomed into the wonderful Python community. At the Education Summit, we’ll put on a young coders’ day on the Saturday, and an educators’ day on the Sunday.

Saturday — young coders’ day

On Saturday we’ll be running a CoderDojo full of workshops on Raspberry Pi and micro:bits for young people aged 7 to 17. If they wish, participants will get to make a project and present it to the conference on the main stage, and everyone will be given a free micro:bit to take home!

Kids’ tickets at just £6 will be available here soon.

Kids on a stage at PyCon UK

Kids presenting their projects to the conference

Sunday — educators’ day

PyCon UK has been bringing developers and educators together ever since it first started its education track in 2011. This year’s Sunday will be a day of professional development: we’ll give teachers, educators, parents, and coding club leaders the chance to learn from us and from each other to build their programming, computing, and digital making skills.

Educator workshop at PyCon UK

Professional development for educators

Educators get a special entrance rate for the conference, starting at £48 — get your tickets now. Financial assistance is also available.

Call for proposals

We invite you to send in your proposal for a talk and workshop at the Education Summit! We’re looking for:

  • 25-minute talks for the educators’ day
  • 50-minute workshops for either the young coders’ or the educators’ day

If you have something you’d like to share, such as a professional development session for educators, advice on best practice for teaching programming, a workshop for up-skilling in Python, or a fun physical computing activity for the CoderDojo, then we’d love to hear about it! Please submit your proposal by 15 June.




After the Education Summit, the conference will continue for two days of talks and a final day of development sprints. Feel free to submit your education-related talk to the main conference too if you want to share it with a wider audience! Check out the PyCon UK 2018 website for more information.

We’re looking forward to seeing you in September!

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Working with the Scout Association on digital skills for life

Post Syndicated from Philip Colligan original https://www.raspberrypi.org/blog/working-with-scout-association-digital-skills-for-life/

Today we’re launching a new partnership between the Scouts and the Raspberry Pi Foundation that will help tens of thousands of young people learn crucial digital skills for life. In this blog post, I want to explain what we’ve got planned, why it matters, and how you can get involved.

This is personal

First, let me tell you why this partnership matters to me. As a child growing up in North Wales in the 1980s, Scouting changed my life. My time with 2nd Rhyl provided me with countless opportunities to grow and develop new skills. It taught me about teamwork and community in ways that continue to shape my decisions today.

As my own kids (now seven and ten) have joined Scouting, I’ve seen the same opportunities opening up for them, and like so many parents, I’ve come back to the movement as a volunteer to support their local section. So this is deeply personal for me, and the same is true for many of my colleagues at the Raspberry Pi Foundation who in different ways have been part of the Scouting movement.

That shouldn’t come as a surprise. Scouting and Raspberry Pi share many of the same values. We are both community-led movements that aim to help young people develop the skills they need for life. We are both powered by an amazing army of volunteers who give their time to support that mission. We both care about inclusiveness, and pride ourselves on combining fun with learning by doing.

Raspberry Pi

Raspberry Pi started life in 2008 as a response to the problem that too many young people were growing up without the skills to create with technology. Our goal is that everyone should be able to harness the power of computing and digital technologies, for work, to solve problems that matter to them, and to express themselves creatively.

In 2012 we launched our first product, the world’s first $35 computer. Just six years on, we have sold over 20 million Raspberry Pi computers and helped kickstart a global movement for digital skills.

The Raspberry Pi Foundation now runs the world’s largest network of volunteer-led computing clubs (Code Clubs and CoderDojos), and creates free educational resources that are used by millions of young people all over the world to learn how to create with digital technologies. And lots of what we are able to achieve is because of partnerships with fantastic organisations that share our goals. For example, through our partnership with the European Space Agency, thousands of young people have written code that has run on two Raspberry Pi computers that Tim Peake took to the International Space Station as part of his Mission Principia.

Digital makers

Today we’re launching the new Digital Maker Staged Activity Badge to help tens of thousands of young people learn how to create with technology through Scouting. Over the past few months, we’ve been working with the Scouts all over the UK to develop and test the new badge requirements, along with guidance, project ideas, and resources that really make them work for Scouting. We know that we need to get two things right: relevance and accessibility.

Relevance is all about making sure that the activities and resources we provide are a really good fit for Scouting and Scouting’s mission to equip young people with skills for life. From the digital compass to nature cameras and the reinvented wide game, we’ve had a lot of fun thinking about ways we can bring to life the crucial role that digital technologies can play in the outdoors and adventure.

Compass Coding with Raspberry Pi

We are beyond excited to be launching a new partnership with the Raspberry Pi Foundation, which will help tens of thousands of young people learn digital skills for life.

We also know that there are great opportunities for Scouts to use digital technologies to solve social problems in their communities, reflecting the movement’s commitment to social action. Today we’re launching the first set of project ideas and resources, with many more to follow over the coming weeks and months.

Accessibility is about providing every Scout leader with the confidence, support, and kit to enable them to offer the Digital Maker Staged Activity Badge to their young people. A lot of work and care has gone into designing activities that require very little equipment: for example, activities at Stages 1 and 2 can be completed with a laptop without access to the internet. For the activities that do require kit, we will be working with Scout Stores and districts to make low-cost kit available to buy or loan.

We’re producing accessible instructions, worksheets, and videos to help leaders run sessions with confidence, and we’ll also be planning training for leaders. We will work with our network of Code Clubs and CoderDojos to connect them with local sections to organise joint activities, bringing both kit and expertise along with them.




Get involved

Today’s launch is just the start. We’ll be developing our partnership over the next few years, and we can’t wait for you to join us in getting more young people making things with technology.

Take a look at the brand-new Raspberry Pi resources designed especially for Scouts, to get young people making and creating right away.

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EC2 Instance Update – C5 Instances with Local NVMe Storage (C5d)

Post Syndicated from Jeff Barr original https://aws.amazon.com/blogs/aws/ec2-instance-update-c5-instances-with-local-nvme-storage-c5d/

As you can see from my EC2 Instance History post, we add new instance types on a regular and frequent basis. Driven by increasingly powerful processors and designed to address an ever-widening set of use cases, the size and diversity of this list reflects the equally diverse group of EC2 customers!

Near the bottom of that list you will find the new compute-intensive C5 instances. With a 25% to 50% improvement in price-performance over the C4 instances, the C5 instances are designed for applications like batch and log processing, distributed and or real-time analytics, high-performance computing (HPC), ad serving, highly scalable multiplayer gaming, and video encoding. Some of these applications can benefit from access to high-speed, ultra-low latency local storage. For example, video encoding, image manipulation, and other forms of media processing often necessitates large amounts of I/O to temporary storage. While the input and output files are valuable assets and are typically stored as Amazon Simple Storage Service (S3) objects, the intermediate files are expendable. Similarly, batch and log processing runs in a race-to-idle model, flushing volatile data to disk as fast as possible in order to make full use of compute resources.

New C5d Instances with Local Storage
In order to meet this need, we are introducing C5 instances equipped with local NVMe storage. Available for immediate use in 5 regions, these instances are a great fit for the applications that I described above, as well as others that you will undoubtedly dream up! Here are the specs:

Instance NamevCPUsRAMLocal StorageEBS BandwidthNetwork Bandwidth
c5d.large24 GiB1 x 50 GB NVMe SSDUp to 2.25 GbpsUp to 10 Gbps
c5d.xlarge48 GiB1 x 100 GB NVMe SSDUp to 2.25 GbpsUp to 10 Gbps
c5d.2xlarge816 GiB1 x 225 GB NVMe SSDUp to 2.25 GbpsUp to 10 Gbps
c5d.4xlarge1632 GiB1 x 450 GB NVMe SSD2.25 GbpsUp to 10 Gbps
c5d.9xlarge3672 GiB1 x 900 GB NVMe SSD4.5 Gbps10 Gbps
c5d.18xlarge72144 GiB2 x 900 GB NVMe SSD9 Gbps25 Gbps

Other than the addition of local storage, the C5 and C5d share the same specs. Both are powered by 3.0 GHz Intel Xeon Platinum 8000-series processors, optimized for EC2 and with full control over C-states on the two largest sizes, giving you the ability to run two cores at up to 3.5 GHz using Intel Turbo Boost Technology.

You can use any AMI that includes drivers for the Elastic Network Adapter (ENA) and NVMe; this includes the latest Amazon Linux, Microsoft Windows (Server 2008 R2, Server 2012, Server 2012 R2 and Server 2016), Ubuntu, RHEL, SUSE, and CentOS AMIs.

Here are a couple of things to keep in mind about the local NVMe storage:

Naming – You don’t have to specify a block device mapping in your AMI or during the instance launch; the local storage will show up as one or more devices (/dev/nvme*1 on Linux) after the guest operating system has booted.

Encryption – Each local NVMe device is hardware encrypted using the XTS-AES-256 block cipher and a unique key. Each key is destroyed when the instance is stopped or terminated.

Lifetime – Local NVMe devices have the same lifetime as the instance they are attached to, and do not stick around after the instance has been stopped or terminated.

Available Now
C5d instances are available in On-Demand, Reserved Instance, and Spot form in the US East (N. Virginia), US West (Oregon), EU (Ireland), US East (Ohio), and Canada (Central) Regions. Prices vary by Region, and are just a bit higher than for the equivalent C5 instances.

Jeff;

PS – We will be adding local NVMe storage to other EC2 instance types in the months to come, so stay tuned!

Puerto Rico’s First Raspberry Pi Educator Workshop

Post Syndicated from Dana Augustin original https://www.raspberrypi.org/blog/puerto-rico-raspberry-pi-workshop/

Earlier this spring, an excited group of STEM educators came together to participate in the first ever Raspberry Pi and Arduino workshop in Puerto Rico.

Their three-day digital making adventure was led by MakerTechPR’s José Rullán and Raspberry Pi Certified Educator Alex Martínez. They ran the event as part of the Robot Makers challenge organized by Yees! and sponsored by Puerto Rico’s Department of Economic Development and Trade to promote entrepreneurial skills within Puerto Rico’s education system.

Over 30 educators attended the workshop, which covered the use of the Raspberry Pi 3 as a computer and digital making resource. The educators received a kit consisting of a Raspberry Pi 3 with an Explorer HAT Pro and an Arduino Uno. At the end of the workshop, the educators were able to keep the kit as a demonstration unit for their classrooms. They were enthusiastic to learn new concepts and immerse themselves in the world of physical computing.

In their first session, the educators were introduced to the Raspberry Pi as an affordable technology for robotic clubs. In their second session, they explored physical computing and the coding languages needed to control the Explorer HAT Pro. They started off coding with Scratch, with which some educators had experience, and ended with controlling the GPIO pins with Python. In the final session, they learned how to develop applications using the powerful combination of Arduino and Raspberry Pi for robotics projects. This gave them a better understanding of how they could engage their students in physical computing.

“The Raspberry Pi ecosystem is the perfect solution in the classroom because to us it is very resourceful and accessible.” – Alex Martínez

Computer science and robotics courses are important for many schools and teachers in Puerto Rico. The simple idea of programming a microcontroller from a $35 computer increases the chances of more students having access to more technology to create things.

Puerto Rico’s education system has faced enormous challenges after Hurricane Maria, including economic collapse and the government’s closure of many schools due to the exodus of families from the island. By attending training like this workshop, educators in Puerto Rico are becoming more experienced in fields like robotics in particular, which are key for 21st-century skills and learning. This, in turn, can lead to more educational opportunities, and hopefully the reopening of more schools on the island.

“We find it imperative that our children be taught STEM disciplines and skills. Our goal is to continue this work of spreading digital making and computer science using the Raspberry Pi around Puerto Rico. We want our children to have the best education possible.” – Alex Martínez

After attending Picademy in 2016, Alex has integrated the Raspberry Pi Foundation’s online resources into his classroom. He has also taught small workshops around the island and in the local Puerto Rican makerspace community. José is an electrical engineer, entrepreneur, educator and hobbyist who enjoys learning to use technology and sharing his knowledge through projects and challenges.

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Hello World Issue 5: Engineering

Post Syndicated from Russell Barnes original https://www.raspberrypi.org/blog/hello-world-issue-5/

Join us as we celebrate the Year of Engineering in the newest issue of Hello World, our magazine for computing and digital making educators.

 

Inspiring future engineers

We’ve brought together a wide range of experts to share their ideas and advice on how to bring engineering to your classroom — read issue 5 to find out the best ways to inspire the next generation.



Plus we’ve got plenty on GP and Scratch, we answer your latest questions, and we bring you our usual collection of useful features, guides, and lesson plans.

Highlights of issue 5 include:

  • The bluffers’ guide to putting together a tech-themed school trip
  • Inclusion, and coding for the visually impaired
  • Getting students interested in databases
  • Why copying may not always be a bad thing

How to get Hello World #5

Hello World is available as a free download under a Creative Commons license for everyone in world who is interested in computer science and digital making education. Get the latest issue as a PDF file straight from the Hello World website.

We’re currently offering free print copies of the magazine to serving educators in the UK. This offer is open to teachers, Code Club and CoderDojo volunteers, teaching assistants, teacher trainers, and others who help children and young people learn about computing and digital making. Subscribe to have your free print magazine posted directly to your home, or subscribe digitally — 20000 educators have already signed up to receive theirs!

Get in touch!

You could write for us about your experiences as an educator, and share your advice with the community. Wherever you are in the world, get in touch by emailing our editorial team about your article idea — we would love to hear from you!

Hello World magazine is a collaboration between the Raspberry Pi Foundation and Computing At School, which is part of the British Computing Society.

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Whimsical builds and messing things up

Post Syndicated from Helen Lynn original https://www.raspberrypi.org/blog/whimsical-builds-and-messing-things-up/

Today is the early May bank holiday in England and Wales, a public holiday, and while this blog rarely rests, the Pi Towers team does. So, while we take a day with our families, our friends, and/or our favourite pastimes, I thought I’d point you at a couple of features from HackSpace magazine, our monthly magazine for makers.

To my mind, they go quite well with a deckchair in the garden, the buzz of a lawnmower a few houses down, and a view of the weeds I ought to have dealt with by now, but I’m sure you’ll find your own ambience.

Make anything with pencils – HackSpace magazine

If you want a unique piece of jewellery to show your love for pencils, follow Peter Brown’s lead. Peter glued twelve pencils together in two rows of six. He then measured the size of his finger and drilled a hole between the glued pencils using a drill bit.

First off, pencils. It hadn’t occurred to me that you could make super useful stuff like a miniature crossbow and a catapult out of pencils. Not only can you do this, you can probably go ahead and do it right now: all you need is a handful of pencils, some rubber bands, some drawing pins, and a bulldog clip (or, as you might prefer, some push pins and a binder clip). The sentence that really leaps out at me here is “To keep a handful of boys aged three to eleven occupied during a family trip, Marie decided to build mini crossbows to help their target practice.” The internet hasn’t helped me find out much about Marie, but I am in awe of her.

If you haven’t wandered off to make a stationery arsenal by now, read Lucy Rogers‘ reflections on making a right mess of things. I hope you do, because I think it’d be great if more people coped better with the fact that we all, unavoidably, fail. You probably won’t really get anywhere without a few goes where you just completely muck it all up.

A ceramic mug, broken into several pieces on the floor

Never mind. We can always line a plant pot with them.
“In Pieces” by dusk-photography / CC BY

This true of everything. Wet lab work and gardening and coding and parenting. And everything. You can share your heroic failures in the comments, if you like, as well as any historic weaponry you have fashioned from the contents of your desk tidy.

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Scanning snacks to your Wunderlist shopping list with Wunderscan

Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/scanning-snacks-to-your-wunderlist-shopping-list/

Brian Carrigan found the remains of a $500 supermarket barcode scanner at a Scrap Exchange for $6.25, and decided to put it to use as a shopping list builder for his pantry.

Raspberry Pi Barcode Scanner Wunderscan Brian Carrigan

Upcycling from scraps

Brian wasn’t planning to build the Wunderscan. But when he stumbled upon the remains of a $500 Cubit barcode scanner at his local reuse center, his inner maker took hold of the situation.

It had been ripped from its connectors and had unlabeled wires hanging from it; a bit of hardware gore if such a thing exists. It was labeled on sale for $6.25, and a quick search revealed that it originally retailed at over $500… I figured I would try to reverse engineer it, and if all else fails, scrap it for the laser and motor.

Brian decided that the scanner, once refurbished with a Raspberry Pi Zero W and new wiring, would make a great addition to his home pantry as a shopping list builder using Wunderlist. “I thought a great use of this would be to keep near our pantry so that when we are out of a spice or snack, we could just scan the item and it would get posted to our shopping list.”

Reverse engineering

The datasheet for the Cubit scanner was available online, and Brian was able to discover the missing pieces required to bring the unit back to working order.

Raspberry Pi Barcode Scanner Wunderscan Brian Carrigan

However, no wiring diagram was provided with the datasheet, so he was forced to figure out the power connections and signal output for himself using a bit of luck and an oscilloscope.

Now that the part was powered and working, all that was left was finding the RS232 transmit line. I used my oscilloscope to do this part and found it by scanning items and looking for the signal. It was not long before this wire was found and I was able to receive UPC codes.

Scanning codes and building (Wunder)lists

When the scanner reads a barcode, it sends the ASCII representation of a UPC code to the attached Raspberry Pi Zero W. Brian used the free UPC Database to convert each code to the name of the corresponding grocery item. Next, he needed to add it to the Wunderlist shopping list that his wife uses for grocery shopping.

Raspberry Pi Barcode Scanner Wunderscan Brian Carrigan

Wunderlist provides an API token so users can incorporate list-making into their projects. With a little extra coding, Brian was able to convert the scanning of a pantry item’s barcode into a new addition to the family shopping list.

Curious as to how it all came together? You can find information on the project, including code and hardware configurations, on Brian’s blog. If you’ve built something similar, we’d love to see it in the comments below.

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A Day in the Life of Michele, Human Resources Coordinator at Backblaze

Post Syndicated from Roderick Bauer original https://www.backblaze.com/blog/day-in-life-human-resources-coordinator/

Michele, HR Coordinator at Backblaze

Most of the time this blog is dedicated to cloud storage and computer backup topics, but we also want our readers to understand the culture and people at Backblaze who all contribute to keeping our company running and making it an enjoyable place to work. We invited our HR Coordinator, Michele, to talk about how she spends her day searching for great candidates to fill employment positions at Backblaze.

What’s a Typical Day for Michele at Backblaze?

After I’ve had a yummy cup of coffee — maybe with a honey and splash of half and half, I’ll generally start my day reviewing resumes and contacting potential candidates to set up an initial phone screen.

When I start the process of filling a position, I’ll spend a lot of time on the phone speaking with potential candidates. During a phone screen call we’ll chat about their experience, background and what they are ideally looking for in their next position. I also ask about what they like to do outside of work, and most importantly, how they feel about office dogs. A candidate may not always look great on paper, but could turn out to be a great cultural fit after speaking with them about their previous experience and what they’re passionate about.

Next, I push strong candidates to the subsequent steps with the hiring managers, which range from setting up a second phone screen, to setting up a Google hangout for completing coding tasks, to scheduling in-person interviews with the team.

At the end of the day after an in-person interview, I’ll check in with all the interviewers to debrief and decide how to proceed with the candidate. Everyone that interviewed the candidate will get together to give feedback. Is there a good cultural fit? Are they someone we’d like to work with? Keeping in contact with the candidates throughout the process and making sure they are organized and informed is a big part of my job. No one likes to wait around and wonder where they are in the process.

In between all the madness, I’ll put together offer letters, send out onboarding paperwork and links, and get all the necessary signatures to move forward.

On the candidate’s first day, I’ll go over benefits and the handbook and make sure everything is going smoothly in their overall orientation as they transition into their new role here at Backblaze!

What Makes Your Job Exciting?

  • I get to speak with many different types of people and see what makes them tick and if they’d be a good fit at Backblaze
  • The fast pace of the job
  • Being constantly kept busy with different tasks including supporting the FUN committee by researching venues and ideas for family day and the holiday party
  • I work on enjoyable projects like creating a people wall for new hires so we are able to put a face to the name
  • Getting to take a mini road trip up to Sacramento each month to check in with the data center employees
  • Constantly learning more and more about the job, the people, and the company

We’re growing rapidly and always looking for great people to join our team at Backblaze. Our team places a premium on open communications, being cleverly unconventional, and helping each other out.

Oh! We also offer competitive salaries, stock options, and amazing benefits.

Which Job Openings are You Currently Trying to Fill?

We are currently looking for the following positions. If you’re interested, please review the job description on our jobs page and then contact me at jobscontact@backblaze.com.

  • Engineering Director
  • Senior Java Engineer
  • Senior Software Engineer
  • Desktop and Laptop Windows Client Programmer
  • Senior Systems Administrator
  • Sales Development Representative

Thanks Michele!

The post A Day in the Life of Michele, Human Resources Coordinator at Backblaze appeared first on Backblaze Blog | Cloud Storage & Cloud Backup.

Tackling climate change and helping the community

Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/fair-haven-weather-station/

In today’s guest post, seventh-grade students Evan Callas, Will Ross, Tyler Fallon, and Kyle Fugate share their story of using the Raspberry Pi Oracle Weather Station in their Innovation Lab class, headed by Raspberry Pi Certified Educator Chris Aviles.

Raspberry Pi Certified Educator Chris Aviles Innovation Lab Oracle Weather Station

United Nations Sustainable Goals

The past couple of weeks in our Innovation Lab class, our teacher, Mr Aviles, has challenged us students to design a project that helps solve one of the United Nations Sustainable Goals. We chose Climate Action. Innovation Lab is a class that gives students the opportunity to learn about where the crossroads of technology, the environment, and entrepreneurship meet. Everyone takes their own paths in innovation and learns about the environment using project-based learning.

Raspberry Pi Certified Educator Chris Aviles Innovation Lab Oracle Weather Station

Raspberry Pi Oracle Weather Station

For our climate change challenge, we decided to build a Raspberry Pi Oracle Weather Station. Tackling the issues of climate change in a way that helps our community stood out to us because we knew with the help of this weather station we can send the local data to farmers and fishermen in town. Recent changes in climate have been affecting farmers’ crops. Unexpected rain, heat, and other unusual weather patterns can completely destabilize the natural growth of the plants and destroy their crops altogether. The amount of labour output needed by farmers has also significantly increased, forcing farmers to grow more food on less resources. By using our Raspberry Pi Oracle Weather Station to alert local farmers, they can be more prepared and aware of the weather, leading to better crops and safe boating.

Raspberry Pi Certified Educator Chris Aviles Innovation Lab Oracle Weather Station

Growing teamwork and coding skills

The process of setting up our weather station was fun and simple. Raspberry Pi made the instructions very easy to understand and read, which was very helpful for our team who had little experience in coding or physical computing. We enjoyed working together as a team and were happy to be growing our teamwork skills.

Once we constructed and coded the weather station, we learned that we needed to support the station with PVC pipes. After we completed these steps, we brought the weather station up to the roof of the school and began collecting data. Our information is currently being sent to the Initial State dashboard so that we can share the information with anyone interested. This information will also be recorded and seen by other schools, businesses, and others from around the world who are using the weather station. For example, we can see the weather in countries such as France, Greece and Italy.

Raspberry Pi Certified Educator Chris Aviles Innovation Lab Oracle Weather Station

Raspberry Pi allows us to build these amazing projects that help us to enjoy coding and physical computing in a fun, engaging, and impactful way. We picked climate change because we care about our community and would like to make a substantial contribution to our town, Fair Haven, New Jersey. It is not every day that kids are given these kinds of opportunities, and we are very lucky and grateful to go to a school and learn from a teacher where these opportunities are given to us. Thanks, Mr Aviles!

To see more awesome projects by Mr Avile’s class, you can keep up with him on his blog and follow him on Twitter.

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StaCoAn – Mobile App Static Analysis Tool

Post Syndicated from Darknet original https://www.darknet.org.uk/2018/04/stacoan-mobile-app-static-analysis-tool/?utm_source=rss&utm_medium=social&utm_campaign=darknetfeed

StaCoAn – Mobile App Static Analysis Tool

StaCoAn is a cross-platform tool which aids developers, bug bounty hunters and ethical hackers performing mobile app static analysis on the code of the application for both native Android and iOS applications.

This tool will look for interesting lines in the code which can contain:

  • Hardcoded credentials
  • API keys
  • URL’s of API’s
  • Decryption keys
  • Major coding mistakes

This tool was created with a big focus on usability and graphical guidance in the user interface.

Read the rest of StaCoAn – Mobile App Static Analysis Tool now! Only available at Darknet.

Invent new sounds with Google’s NSynth Super

Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/google-nsynth-super/

Discover new sounds and explore the role of machine learning in music production and sound research with the NSynth Super, an ongoing project from Google’s Magenta research team that you can build at home.

Google Open NSynth Super Testing

Uploaded by AB Open on 2018-04-17.

What is the NSynth Super?

Part of the ongoing Magenta research project within Google, NSynth Super explores the ways in which machine learning tools help artists and musicians be creative.

Google Nsynth Super Raspberry Pi

“Technology has always played a role in creating new types of sounds that inspire musicians — from the sounds of distortion to the electronic sounds of synths,” explains the team behind the NSynth Super. “Today, advances in machine learning and neural networks have opened up new possibilities for sound generation.”

Using TensorFlow, the Magenta team builds tools and interfaces that let  artists and musicians use machine learning in their work. The NSynth Super AI algorithm uses deep neural networking to investigate the character of sounds. It then builds new sounds based on these characteristics instead of simply mixing sounds together.

Using an autoencoder, it extracts 16 defining temporal features from each input. These features are then interpolated linearly to create new embeddings (mathematical representations of each sound). These new embeddings are then decoded into new sounds, which have the acoustic qualities of both inputs.

The team publishes all hardware designs and software that are part of their ongoing research under open-source licences, allowing you to build your own synth.

Build your own NSynth Super

Using these open-source tools, Andrew Black has produced his own NSynth Super, demoed in the video above. Andrew’s list of build materials includes a Raspberry Pi 3, potentiometers, rotary encoders, and the Adafruit 1.3″ OLED display. Magenta also provides Gerber files for you to fabricate your own PCB.

Google Nsynth Super Raspberry Pi

Once fabricated, the PCB includes a table of contents for adding components.

The build isn’t easy — it requires soldering skills or access to someone who can assemble PCBs. Take a look at Andrew’s blog post and the official NSynth GitHub repo to see whether you’re up to the challenge.

Google Nsynth Super Raspberry Pi
Google Nsynth Super Raspberry Pi
Google Nsynth Super Raspberry Pi

Music and Raspberry Pi

The Raspberry Pi has been widely used for music production and music builds. Be it retrofitting a boombox, distributing music atop Table Mountain, or coding tracks with Sonic Pi, the Pi offers endless opportunities for musicians and music lovers to expand their repertoire of builds and instruments.

If you’d like to try more music-based projects using the Raspberry Pi, you can check out our free resources. And if you’ve used a Raspberry Pi in your own musical project, please share it with us in the comments or via our social network accounts.

The post Invent new sounds with Google’s NSynth Super appeared first on Raspberry Pi.

Start a CoderDojo with our free online training

Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/start-a-coderdojo-with-our-free-online-training/

You can now sign up to our newest free online course Start a CoderDojo to learn more about CoderDojo and how you can easily set up one of these free coding clubs for young people in your area. With less than two weeks until the course begins, we wanted to tell you about the course’s content and why the course’s creator put it together for you.

Start a CoderDojo || free online learning || Raspberry Pi Foundation

Get support and advice on how to grow your confidence in coding and start a CoderDojo for young people in your area.

What is CoderDojo?

CoderDojo is a global network of free, volunteer-led, community-based programming clubs for young people aged 7 to 17. There are currently more than 1700 Dojos running regularly across 75 countries. All of these clubs were started by individuals who are passionate about giving young people the opportunity to learn to code. Some people assume you need technical skills to start a Dojo, but that’s not true. The most important thing is that you can bring people together for a shared goal.

What is covered on the course?

The course was developed by Philip, CoderDojo’s Educational Content Lead. It gives those who think empowering young people to be tech creators is important the resources and supports to achieve that goal by starting a Dojo. Divided over three weeks and running for about four hours in total, the course provides practical advice and resources on everything you need to know to plan and run a fun, social, and creative coding club for young people.

“In the first week, you’ll look at what coding is, at the worldwide CoderDojo community of coding clubs, and at the creative approach CoderDojos take to helping young people learn to code. In week two, you’ll move on to setting up your Dojo with a team, a venue, and any needed materials. You’ll also look at how to find young people to attend. Week three wraps up the course by giving you sample plans for a Dojo session and a Dojo’s year, and we’ll be talking about how to grow and develop your Dojo over time as your attendees become better coders.”
— Philip

Who is the course for?

Anyone interested in enabling young people to be tech creators should take this course. Parents, teachers, librarians, IT professionals, youth workers, and others have all started Dojos in their community. They say that “it’s an amazing experience that led [them] to expand [their] personal horizons”, and that they “find it really rewarding”.

The course is free and open to all — if you’re interested, then sign up now.

If you’re already mentoring at a Dojo, the course is a great opportunity to revise what you’ve learnt, and a chance to share your insights with newcomers in the discussion sections. Parents and guardians who wish to learn more about CoderDojo and are considering getting involved are also more than welcome to join.

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Cloud Empire: Meet the Rebel Alliance

Post Syndicated from Roderick Bauer original https://www.backblaze.com/blog/cloud-empire-meet-the-rebel-alliance/

Cloud Empire: Meet the Rebel Alliance

Last week Backblaze made the exciting announcement that through partnerships with Packet and ServerCentral, cloud computing is available to Backblaze B2 Cloud Storage customers.

Those of you familiar with cloud computing will understand the significance of this news. We are now offering the least expensive cloud storage + cloud computing available anywhere. You no longer have to submit to the lock-in tactics and exorbitant prices charged by the other big players in the cloud services biz.

As Robin Harris wrote in ZDNet about last week’s computing partners announcement, Cloud Empire: Meet the Rebel Alliance.

We understand that some of our cloud backup and storage customers might be unfamiliar with cloud computing. Backblaze made its name in cloud backup and object storage, and that’s what our customers know us for. In response to customers requests, we’ve directly connected our B2 cloud object storage with cloud compute providers. This adds the ability to use and run programs on data once it’s in the B2 cloud, opening up a world of new uses for B2. Just some of the possibilities include media transcoding and rendering, web hosting, application development and testing, business analytics, disaster recovery, on-demand computing capacity (cloud bursting), AI, and mobile and IoT applications.

The world has been moving to a multi-cloud / hybrid cloud world, and customers are looking for more choices than those offered by the existing cloud players. Our B2 compute partnerships build on our mission to offer cloud storage that’s astonishingly easy and low-cost. They enable our customers to move into a more flexible and affordable cloud services ecosystem that provides a greater variety of choices and costs far less. We believe we are helping to fulfill the promise of the internet by allowing customers to choose the best-of-breed services from the best vendors.

If You’re Not Familiar with Cloud Computing, Here’s a Quick Overview

Cloud computing is another component of cloud services, like object storage, that replicates in the cloud a basic function of a computer system. Think of services that operate in a cloud as an infinitely scalable version of what happens on your desktop computer. In your desktop computer you have computing/processing (CPU), fast storage (like an SSD), data storage (like your disk drive), and memory (RAM). Their counterparts in the cloud are computing (CPU), block storage (fast storage), object storage (data storage), and processing memory (RAM).

Computer building blocks

CPU, RAM, fast internal storage, and a hard drive are the basic building blocks of a computer
They also are the basic building blocks of cloud computing

Some customers require only some of these services, such as cloud storage. B2 as a standalone service has proven to be an outstanding solution for those customers interested in backing up or archiving data. There are many customers that would like additional capabilities, such as performing operations on that data once it’s in the cloud. They need object storage combined with computing.

With the just announced compute partnerships, Backblaze is able to offer computing services to anyone using B2. A direct connection between Backblaze’s and our partners’ data centers means that our customers can process data stored in B2 with high speed, low latency, and zero data transfer costs.

Backblaze, Packet and Server Central cloud compute workflow diagram

Cloud service providers package up CPU, storage, and memory into services that you can rent on an hourly basis
You can scale up and down and add or remove services as you need them

How Does Computing + B2 Work?

Those wanting to use B2 with computing will need to sign up for accounts with Backblaze and either Packet or ServerCentral. Packet customers need only select “SJC1” as their region and then get started. The process is also simple for ServerCentral customers — they just need to register with a ServerCentral account rep.

The direct connection between B2 and our compute partners means customers will experience very low latency (less than 10ms) between services. Even better, all data transfers between B2 and the compute partner are free. When combined with Backblaze B2, customers can obtain cloud computing services for as little as 50% of the cost of Amazon’s Elastic Compute Cloud (EC2).

Opening Up the Cloud “Walled Garden”

Traditionally, cloud vendors charge fees for customers to move data outside the “walled garden” of that particular vendor. These fees reach upwards of $0.12 per gigabyte (GB) for data egress. This large fee for customers accessing their own data restricts users from using a multi-cloud approach and taking advantage of less expensive or better performing options. With free transfers between B2 and Packet or ServerCentral, customers now have a predictable, scalable solution for computing and data storage while avoiding vendor lock in. Dropbox made waves when they saved $75 million by migrating off of AWS. Adding computing to B2 helps anyone interested in moving some or all of their computing off of AWS and thereby cutting their AWS bill by 50% or more.

What are the Advantages of Cloud Storage + Computing?

Using computing and storage in the cloud provide a number of advantages over using in-house resources.

  1. You don’t have to purchase the actual hardware, software licenses, and provide space and IT resources for the systems.
  2. Cloud computing is available with just a few minutes notice and you only pay for whatever period of time you need. You avoid having additional hardware on your balance sheet.
  3. Resources are in the cloud and can provide online services to customers, mobile users, and partners located anywhere in the world.
  4. You can isolate the work on these systems from your normal production environment, making them ideal for testing and trying out new applications and development projects.
  5. Computing resources scale when you need them to, providing temporary or ongoing extra resources for expected or unexpected demand.
  6. They can provide redundant and failover services when and if your primary systems are unavailable for whatever reason.

Where Can I Learn More?

We encourage B2 customers to explore the options available at our partner sites, Packet and ServerCentral. They are happy to help customers understand what services are available and how to get started.

We are excited to see what you build! And please tell us in the comments what you are doing or have planned with B2 + computing.

P.S. May the force be with all of us!

The post Cloud Empire: Meet the Rebel Alliance appeared first on Backblaze Blog | Cloud Storage & Cloud Backup.

Community profile: Dave Akerman

Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/community-profile-dave-akerman/

This column is from The MagPi issue 61. You can download a PDF of the full issue for free, or subscribe to receive the print edition through your letterbox or the digital edition on your tablet. All proceeds from the print and digital editions help the Raspberry Pi Foundation achieve our charitable goals.

The pinned tweet on Dave Akerman’s Twitter account shows a table displaying the various components needed for a high-altitude balloon (HAB) flight. Batteries, leads, a camera and Raspberry Pi, plus an unusually themed payload. The caption reads ‘The Queen, The Duke of York, and my TARDIS”, and sums up Dave’s maker career in a heartbeat.

David Akerman on Twitter

The Queen, The Duke of York, and my TARDIS 🙂 #UKHAS #RaspberryPi

Though writing software for industrial automation pays the bills, the majority of Dave’s time is spent in the world of high-altitude ballooning and the ever-growing community that encompasses it. And, while he makes some money sending business-themed balloons to near space for the likes of Aardman Animations, Confused.com, and the BBC, Dave is best known in the Raspberry Pi community for his use of the small computer in every payload, and his work as a tutor alongside the Foundation’s staff at Skycademy events.

Dave Akerman The MagPi Raspberry Pi Community Profile

Dave continues to help others while breaking records and having a good time exploring the atmosphere.

Dave has dedicated many hours and many, many more miles to assist with the Foundation’s Skycademy programme, helping to explore high-altitude ballooning with educators from across the UK. Using a Raspberry Pi and various other pieces of lightweight tech, Dave and Foundation staff member James Robinson explored the incorporation of high-altitude ballooning into education. Through Skycademy, educators were able to learn new skills and take them to the classroom, setting off their own balloons with their students, and recording the results on Raspberry Pis.

Dave Akerman The MagPi Raspberry Pi Community Profile

Dave’s most recent flight broke a new record. On 13 August 2017, his HAB payload was able to send back the highest images taken by any amateur flight.

But education isn’t the only reason for Dave’s involvement in the HAB community. As with anyone passionate about a specific hobby, Dave strives to break records. The most recent record-breaking flight took place on 13 August 2017, when Dave’s Raspberry Pi Zero HAB sent home the highest images taken by any amateur high-altitude balloon launch: at 43014 metres. No other HAB balloon has provided images from such an altitude, and the lightweight nature of the Pi Zero definitely helped, as Dave went on to mention on Twitter a few days later.

Dave Akerman The MagPi Raspberry Pi Community Profile

Dave is recognised as being the first person to incorporate a Raspberry Pi into a HAB payload, and continues to break records with the help of the little green board. More recently, he’s been able to lighten the load by using the Raspberry Pi Zero.

When the first Pi made its way to near space, Dave tore the computer apart in order to meet the weight restriction. The Pi in the Sky board was created to add the extra features needed for the flight. Since then, the HAT has experienced a few changes.

Dave Akerman The MagPi Raspberry Pi Community Profile

The Pi in the Sky board, created specifically for HAB flights.

Dave first fell in love with high-altitude ballooning after coming across the hobby in a video shared on a photographic forum. With a lifelong interest in space thanks to watching the Moon landings as a boy, plus a talent for electronics and photography, it seems a natural progression for him. Throw in his coding skills from learning to program on a Teletype and it’s no wonder he was ready and eager to take to the skies, so to speak, and capture the curvature of the Earth. What was so great about using the Raspberry Pi was the instant gratification he got from receiving images in real time as they were taken during the flight. While other devices could control a camera and store captured images for later retrieval, thanks to the Pi Dave was able to transmit the files back down to Earth and check the progress of his balloon while attempting to break records with a flight.

Dave Akerman The MagPi Raspberry Pi Community Profile Morph

One of the many commercial flights Dave has organised featured the classic children’s TV character Morph, a creation of the Aardman Animations studio known for Wallace and Gromit. Morph took to the sky twice in his mission to reach near space, and finally succeeded in 2016.

High-altitude ballooning isn’t the only part of Dave’s life that incorporates a Raspberry Pi. Having “lost count” of how many Pis he has running tasks, Dave has also created radio receivers for APRS (ham radio data), ADS-B (aircraft tracking), and OGN (gliders), along with a time-lapse camera in his garden, and he has a few more Pi for tinkering purposes.

The post Community profile: Dave Akerman appeared first on Raspberry Pi.

Rotate Amazon RDS database credentials automatically with AWS Secrets Manager

Post Syndicated from Apurv Awasthi original https://aws.amazon.com/blogs/security/rotate-amazon-rds-database-credentials-automatically-with-aws-secrets-manager/

Recently, we launched AWS Secrets Manager, a service that makes it easier to rotate, manage, and retrieve database credentials, API keys, and other secrets throughout their lifecycle. You can configure Secrets Manager to rotate secrets automatically, which can help you meet your security and compliance needs. Secrets Manager offers built-in integrations for MySQL, PostgreSQL, and Amazon Aurora on Amazon RDS, and can rotate credentials for these databases natively. You can control access to your secrets by using fine-grained AWS Identity and Access Management (IAM) policies. To retrieve secrets, employees replace plaintext secrets with a call to Secrets Manager APIs, eliminating the need to hard-code secrets in source code or update configuration files and redeploy code when secrets are rotated.

In this post, I introduce the key features of Secrets Manager. I then show you how to store a database credential for a MySQL database hosted on Amazon RDS and how your applications can access this secret. Finally, I show you how to configure Secrets Manager to rotate this secret automatically.

Key features of Secrets Manager

These features include the ability to:

  • Rotate secrets safely. You can configure Secrets Manager to rotate secrets automatically without disrupting your applications. Secrets Manager offers built-in integrations for rotating credentials for Amazon RDS databases for MySQL, PostgreSQL, and Amazon Aurora. You can extend Secrets Manager to meet your custom rotation requirements by creating an AWS Lambda function to rotate other types of secrets. For example, you can create an AWS Lambda function to rotate OAuth tokens used in a mobile application. Users and applications retrieve the secret from Secrets Manager, eliminating the need to email secrets to developers or update and redeploy applications after AWS Secrets Manager rotates a secret.
  • Secure and manage secrets centrally. You can store, view, and manage all your secrets. By default, Secrets Manager encrypts these secrets with encryption keys that you own and control. Using fine-grained IAM policies, you can control access to secrets. For example, you can require developers to provide a second factor of authentication when they attempt to retrieve a production database credential. You can also tag secrets to help you discover, organize, and control access to secrets used throughout your organization.
  • Monitor and audit easily. Secrets Manager integrates with AWS logging and monitoring services to enable you to meet your security and compliance requirements. For example, you can audit AWS CloudTrail logs to see when Secrets Manager rotated a secret or configure AWS CloudWatch Events to alert you when an administrator deletes a secret.
  • Pay as you go. Pay for the secrets you store in Secrets Manager and for the use of these secrets; there are no long-term contracts or licensing fees.

Get started with Secrets Manager

Now that you’re familiar with the key features, I’ll show you how to store the credential for a MySQL database hosted on Amazon RDS. To demonstrate how to retrieve and use the secret, I use a python application running on Amazon EC2 that requires this database credential to access the MySQL instance. Finally, I show how to configure Secrets Manager to rotate this database credential automatically. Let’s get started.

Phase 1: Store a secret in Secrets Manager

  1. Open the Secrets Manager console and select Store a new secret.
     
    Secrets Manager console interface
     
  2. I select Credentials for RDS database because I’m storing credentials for a MySQL database hosted on Amazon RDS. For this example, I store the credentials for the database superuser. I start by securing the superuser because it’s the most powerful database credential and has full access over the database.
     
    Store a new secret interface with Credentials for RDS database selected
     

    Note: For this example, you need permissions to store secrets in Secrets Manager. To grant these permissions, you can use the AWSSecretsManagerReadWriteAccess managed policy. Read the AWS Secrets Manager Documentation for more information about the minimum IAM permissions required to store a secret.

  3. Next, I review the encryption setting and choose to use the default encryption settings. Secrets Manager will encrypt this secret using the Secrets Manager DefaultEncryptionKeyDefaultEncryptionKey in this account. Alternatively, I can choose to encrypt using a customer master key (CMK) that I have stored in AWS KMS.
     
    Select the encryption key interface
     
  4. Next, I view the list of Amazon RDS instances in my account and select the database this credential accesses. For this example, I select the DB instance mysql-rds-database, and then I select Next.
     
    Select the RDS database interface
     
  5. In this step, I specify values for Secret Name and Description. For this example, I use Applications/MyApp/MySQL-RDS-Database as the name and enter a description of this secret, and then select Next.
     
    Secret Name and description interface
     
  6. For the next step, I keep the default setting Disable automatic rotation because my secret is used by my application running on Amazon EC2. I’ll enable rotation after I’ve updated my application (see Phase 2 below) to use Secrets Manager APIs to retrieve secrets. I then select Next.

    Note: If you’re storing a secret that you’re not using in your application, select Enable automatic rotation. See our AWS Secrets Manager getting started guide on rotation for details.

     
    Configure automatic rotation interface
     

  7. Review the information on the next screen and, if everything looks correct, select Store. We’ve now successfully stored a secret in Secrets Manager.
  8. Next, I select See sample code.
     
    The See sample code button
     
  9. Take note of the code samples provided. I will use this code to update my application to retrieve the secret using Secrets Manager APIs.
     
    Python sample code
     

Phase 2: Update an application to retrieve secret from Secrets Manager

Now that I have stored the secret in Secrets Manager, I update my application to retrieve the database credential from Secrets Manager instead of hard coding this information in a configuration file or source code. For this example, I show how to configure a python application to retrieve this secret from Secrets Manager.

  1. I connect to my Amazon EC2 instance via Secure Shell (SSH).
  2. Previously, I configured my application to retrieve the database user name and password from the configuration file. Below is the source code for my application.
    import MySQLdb
    import config

    def no_secrets_manager_sample()

    # Get the user name, password, and database connection information from a config file.
    database = config.database
    user_name = config.user_name
    password = config.password

    # Use the user name, password, and database connection information to connect to the database
    db = MySQLdb.connect(database.endpoint, user_name, password, database.db_name, database.port)

  3. I use the sample code from Phase 1 above and update my application to retrieve the user name and password from Secrets Manager. This code sets up the client and retrieves and decrypts the secret Applications/MyApp/MySQL-RDS-Database. I’ve added comments to the code to make the code easier to understand.
    # Use the code snippet provided by Secrets Manager.
    import boto3
    from botocore.exceptions import ClientError

    def get_secret():
    #Define the secret you want to retrieve
    secret_name = "Applications/MyApp/MySQL-RDS-Database"
    #Define the Secrets mManager end-point your code should use.
    endpoint_url = "https://secretsmanager.us-east-1.amazonaws.com"
    region_name = "us-east-1"

    #Setup the client
    session = boto3.session.Session()
    client = session.client(
    service_name='secretsmanager',
    region_name=region_name,
    endpoint_url=endpoint_url
    )

    #Use the client to retrieve the secret
    try:
    get_secret_value_response = client.get_secret_value(
    SecretId=secret_name
    )
    #Error handling to make it easier for your code to tolerate faults
    except ClientError as e:
    if e.response['Error']['Code'] == 'ResourceNotFoundException':
    print("The requested secret " + secret_name + " was not found")
    elif e.response['Error']['Code'] == 'InvalidRequestException':
    print("The request was invalid due to:", e)
    elif e.response['Error']['Code'] == 'InvalidParameterException':
    print("The request had invalid params:", e)
    else:
    # Decrypted secret using the associated KMS CMK
    # Depending on whether the secret was a string or binary, one of these fields will be populated
    if 'SecretString' in get_secret_value_response:
    secret = get_secret_value_response['SecretString']
    else:
    binary_secret_data = get_secret_value_response['SecretBinary']

    # Your code goes here.

  4. Applications require permissions to access Secrets Manager. My application runs on Amazon EC2 and uses an IAM role to obtain access to AWS services. I will attach the following policy to my IAM role. This policy uses the GetSecretValue action to grant my application permissions to read secret from Secrets Manager. This policy also uses the resource element to limit my application to read only the Applications/MyApp/MySQL-RDS-Database secret from Secrets Manager. You can visit the AWS Secrets Manager Documentation to understand the minimum IAM permissions required to retrieve a secret.
    {
    "Version": "2012-10-17",
    "Statement": {
    "Sid": "RetrieveDbCredentialFromSecretsManager",
    "Effect": "Allow",
    "Action": "secretsmanager:GetSecretValue",
    "Resource": "arn:aws:secretsmanager:::secret:Applications/MyApp/MySQL-RDS-Database"
    }
    }

Phase 3: Enable Rotation for Your Secret

Rotating secrets periodically is a security best practice because it reduces the risk of misuse of secrets. Secrets Manager makes it easy to follow this security best practice and offers built-in integrations for rotating credentials for MySQL, PostgreSQL, and Amazon Aurora databases hosted on Amazon RDS. When you enable rotation, Secrets Manager creates a Lambda function and attaches an IAM role to this function to execute rotations on a schedule you define.

Note: Configuring rotation is a privileged action that requires several IAM permissions and you should only grant this access to trusted individuals. To grant these permissions, you can use the AWS IAMFullAccess managed policy.

Next, I show you how to configure Secrets Manager to rotate the secret Applications/MyApp/MySQL-RDS-Database automatically.

  1. From the Secrets Manager console, I go to the list of secrets and choose the secret I created in the first step Applications/MyApp/MySQL-RDS-Database.
     
    List of secrets in the Secrets Manager console
     
  2. I scroll to Rotation configuration, and then select Edit rotation.
     
    Rotation configuration interface
     
  3. To enable rotation, I select Enable automatic rotation. I then choose how frequently I want Secrets Manager to rotate this secret. For this example, I set the rotation interval to 60 days.
     
    Edit rotation configuration interface
     
  4. Next, Secrets Manager requires permissions to rotate this secret on your behalf. Because I’m storing the superuser database credential, Secrets Manager can use this credential to perform rotations. Therefore, I select Use the secret that I provided in step 1, and then select Next.
     
    Select which secret to use in the Edit rotation configuration interface
     
  5. The banner on the next screen confirms that I have successfully configured rotation and the first rotation is in progress, which enables you to verify that rotation is functioning as expected. Secrets Manager will rotate this credential automatically every 60 days.
     
    Confirmation banner message
     

Summary

I introduced AWS Secrets Manager, explained the key benefits, and showed you how to help meet your compliance requirements by configuring AWS Secrets Manager to rotate database credentials automatically on your behalf. Secrets Manager helps you protect access to your applications, services, and IT resources without the upfront investment and on-going maintenance costs of operating your own secrets management infrastructure. To get started, visit the Secrets Manager console. To learn more, visit Secrets Manager documentation.

If you have comments about this post, submit them in the Comments section below. If you have questions about anything in this post, start a new thread on the Secrets Manager forum.

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Engineering deep dive: Encoding of SCTs in certificates

Post Syndicated from Let's Encrypt - Free SSL/TLS Certificates original https://letsencrypt.org/2018/04/04/sct-encoding.html

<p>Let&rsquo;s Encrypt recently <a href="https://community.letsencrypt.org/t/signed-certificate-timestamps-embedded-in-certificates/57187">launched SCT embedding in
certificates</a>.
This feature allows browsers to check that a certificate was submitted to a
<a href="https://en.wikipedia.org/wiki/Certificate_Transparency">Certificate Transparency</a>
log. As part of the launch, we did a thorough review
that the encoding of Signed Certificate Timestamps (SCTs) in our certificates
matches the relevant specifications. In this post, I&rsquo;ll dive into the details.
You&rsquo;ll learn more about X.509, ASN.1, DER, and TLS encoding, with references to
the relevant RFCs.</p>

<p>Certificate Transparency offers three ways to deliver SCTs to a browser: In a
TLS extension, in stapled OCSP, or embedded in a certificate. We chose to
implement the embedding method because it would just work for Let&rsquo;s Encrypt
subscribers without additional work. In the SCT embedding method, we submit
a &ldquo;precertificate&rdquo; with a <a href="#poison">poison extension</a> to a set of
CT logs, and get back SCTs. We then issue a real certificate based on the
precertificate, with two changes: The poison extension is removed, and the SCTs
obtained earlier are added in another extension.</p>

<p>Given a certificate, let&rsquo;s first look for the SCT list extension. According to CT (<a href="https://tools.ietf.org/html/rfc6962#section-3.3">RFC 6962
section 3.3</a>),
the extension OID for a list of SCTs is <code>1.3.6.1.4.1.11129.2.4.2</code>. An <a href="http://www.hl7.org/Oid/information.cfm">OID (object
ID)</a> is a series of integers, hierarchically
assigned and globally unique. They are used extensively in X.509, for instance
to uniquely identify extensions.</p>

<p>We can <a href="https://acme-v01.api.letsencrypt.org/acme/cert/031f2484307c9bc511b3123cb236a480d451">download an example certificate</a>,
and view it using OpenSSL (if your OpenSSL is old, it may not display the
detailed information):</p>

<pre><code>$ openssl x509 -noout -text -inform der -in Downloads/031f2484307c9bc511b3123cb236a480d451

CT Precertificate SCTs:
Signed Certificate Timestamp:
Version : v1(0)
Log ID : DB:74:AF:EE:CB:29:EC:B1:FE:CA:3E:71:6D:2C:E5:B9:
AA:BB:36:F7:84:71:83:C7:5D:9D:4F:37:B6:1F:BF:64
Timestamp : Mar 29 18:45:07.993 2018 GMT
Extensions: none
Signature : ecdsa-with-SHA256
30:44:02:20:7E:1F:CD:1E:9A:2B:D2:A5:0A:0C:81:E7:
13:03:3A:07:62:34:0D:A8:F9:1E:F2:7A:48:B3:81:76:
40:15:9C:D3:02:20:65:9F:E9:F1:D8:80:E2:E8:F6:B3:
25:BE:9F:18:95:6D:17:C6:CA:8A:6F:2B:12:CB:0F:55:
FB:70:F7:59:A4:19
Signed Certificate Timestamp:
Version : v1(0)
Log ID : 29:3C:51:96:54:C8:39:65:BA:AA:50:FC:58:07:D4:B7:
6F:BF:58:7A:29:72:DC:A4:C3:0C:F4:E5:45:47:F4:78
Timestamp : Mar 29 18:45:08.010 2018 GMT
Extensions: none
Signature : ecdsa-with-SHA256
30:46:02:21:00:AB:72:F1:E4:D6:22:3E:F8:7F:C6:84:
91:C2:08:D2:9D:4D:57:EB:F4:75:88:BB:75:44:D3:2F:
95:37:E2:CE:C1:02:21:00:8A:FF:C4:0C:C6:C4:E3:B2:
45:78:DA:DE:4F:81:5E:CB:CE:2D:57:A5:79:34:21:19:
A1:E6:5B:C7:E5:E6:9C:E2
</code></pre>

<p>Now let&rsquo;s go a little deeper. How is that extension represented in
the certificate? Certificates are expressed in
<a href="https://en.wikipedia.org/wiki/Abstract_Syntax_Notation_One">ASN.1</a>,
which generally refers to both a language for expressing data structures
and a set of formats for encoding them. The most common format,
<a href="https://en.wikipedia.org/wiki/X.690#DER_encoding">DER</a>,
is a tag-length-value format. That is, to encode an object, first you write
down a tag representing its type (usually one byte), then you write
down a number expressing how long the object is, then you write down
the object contents. This is recursive: An object can contain multiple
objects within it, each of which has its own tag, length, and value.</p>

<p>One of the cool things about DER and other tag-length-value formats is that you
can decode them to some degree without knowing what they mean. For instance, I
can tell you that 0x30 means the data type &ldquo;SEQUENCE&rdquo; (a struct, in ASN.1
terms), and 0x02 means &ldquo;INTEGER&rdquo;, then give you this hex byte sequence to
decode:</p>

<pre><code>30 06 02 01 03 02 01 0A
</code></pre>

<p>You could tell me right away that decodes to:</p>

<pre><code>SEQUENCE
INTEGER 3
INTEGER 10
</code></pre>

<p>Try it yourself with this great <a href="https://lapo.it/asn1js/#300602010302010A">JavaScript ASN.1
decoder</a>. However, you wouldn&rsquo;t know
what those integers represent without the corresponding ASN.1 schema (or
&ldquo;module&rdquo;). For instance, if you knew that this was a piece of DogData, and the
schema was:</p>

<pre><code>DogData ::= SEQUENCE {
legs INTEGER,
cutenessLevel INTEGER
}
</code></pre>

<p>You&rsquo;d know this referred to a three-legged dog with a cuteness level of 10.</p>

<p>We can take some of this knowledge and apply it to our certificates. As a first
step, convert the above certificate to hex with
<code>xxd -ps &lt; Downloads/031f2484307c9bc511b3123cb236a480d451</code>. You can then copy
and paste the result into
<a href="https://lapo.it/asn1js">lapo.it/asn1js</a> (or use <a href="https://lapo.it/asn1js/#3082062F30820517A0030201020212031F2484307C9BC511B3123CB236A480D451300D06092A864886F70D01010B0500304A310B300906035504061302555331163014060355040A130D4C6574277320456E6372797074312330210603550403131A4C6574277320456E637279707420417574686F72697479205833301E170D3138303332393137343530375A170D3138303632373137343530375A302D312B3029060355040313223563396137662E6C652D746573742E686F66666D616E2D616E64726577732E636F6D30820122300D06092A864886F70D01010105000382010F003082010A0282010100BCEAE8F504D9D91FCFC69DB943254A7FED7C6A3C04E2D5C7DDD010CBBC555887274489CA4F432DCE6D7AB83D0D7BDB49C466FBCA93102DC63E0EB1FB2A0C50654FD90B81A6CB357F58E26E50F752BF7BFE9B56190126A47409814F59583BDD337DFB89283BE22E81E6DCE13B4E21FA6009FC8A7F903A17AB05C8BED85A715356837E849E571960A8999701EAE9CE0544EAAB936B790C3C35C375DB18E9AA627D5FA3579A0FB5F8079E4A5C9BE31C2B91A7F3A63AFDFEDB9BD4EA6668902417D286BE4BBE5E43CD9FE1B8954C06F21F5C5594FD3AB7D7A9CBD6ABF19774D652FD35C5718C25A3BA1967846CED70CDBA95831CF1E09FF7B8014E63030CE7A776750203010001A382032A30820326300E0603551D0F0101FF0404030205A0301D0603551D250416301406082B0601050507030106082B06010505070302300C0603551D130101FF04023000301D0603551D0E041604148B3A21ABADF50C4B30DCCD822724D2C4B9BA29E3301F0603551D23041830168014A84A6A63047DDDBAE6D139B7A64565EFF3A8ECA1306F06082B0601050507010104633061302E06082B060105050730018622687474703A2F2F6F6373702E696E742D78332E6C657473656E63727970742E6F7267302F06082B060105050730028623687474703A2F2F636572742E696E742D78332E6C657473656E63727970742E6F72672F302D0603551D110426302482223563396137662E6C652D746573742E686F66666D616E2D616E64726577732E636F6D3081FE0603551D200481F63081F33008060667810C0102013081E6060B2B0601040182DF130101013081D6302606082B06010505070201161A687474703A2F2F6370732E6C657473656E63727970742E6F72673081AB06082B0601050507020230819E0C819B54686973204365727469666963617465206D6179206F6E6C792062652072656C6965642075706F6E2062792052656C79696E67205061727469657320616E64206F6E6C7920696E206163636F7264616E636520776974682074686520436572746966696361746520506F6C69637920666F756E642061742068747470733A2F2F6C657473656E63727970742E6F72672F7265706F7369746F72792F30820104060A2B06010401D6790204020481F50481F200F0007500DB74AFEECB29ECB1FECA3E716D2CE5B9AABB36F7847183C75D9D4F37B61FBF64000001627313EB19000004030046304402207E1FCD1E9A2BD2A50A0C81E713033A0762340DA8F91EF27A48B3817640159CD30220659FE9F1D880E2E8F6B325BE9F18956D17C6CA8A6F2B12CB0F55FB70F759A419007700293C519654C83965BAAA50FC5807D4B76FBF587A2972DCA4C30CF4E54547F478000001627313EB2A0000040300483046022100AB72F1E4D6223EF87FC68491C208D29D4D57EBF47588BB7544D32F9537E2CEC10221008AFFC40CC6C4E3B24578DADE4F815ECBCE2D57A579342119A1E65BC7E5E69CE2300D06092A864886F70D01010B0500038201010095F87B663176776502F792DDD232C216943C7803876FCBEB46393A36354958134482E0AFEED39011618327C2F0203351758FEB420B73CE6C797B98F88076F409F3903F343D1F5D9540F41EF47EB39BD61B62873A44F00B7C8B593C6A416458CF4B5318F35235BC88EABBAA34F3E3F81BD3B047E982EE1363885E84F76F2F079F2B6EEB4ECB58EFE74C8DE7D54DE5C89C4FB5BB0694B837BD6F02BAFD5A6C007D1B93D25007BDA9B2BDBF82201FE1B76B628CE34E2D974E8E623EC57A5CB53B435DD4B9993ADF6BA3972F2B29D259594A94E17BBE06F34AAE5CF0F50297548C4DFFC5566136F78A3D3B324EAE931A14EB6BE6DA1D538E48CF077583C67B52E7E8">this handy link</a>). You can also run <code>openssl asn1parse -i -inform der -in Downloads/031f2484307c9bc511b3123cb236a480d451</code> to use OpenSSL&rsquo;s parser, which is less easy to use in some ways, but easier to copy and paste.</p>

<p>In the decoded data, we can find the OID <code>1.3.6.1.4.1.11129.2.4.2</code>, indicating
the SCT list extension. Per <a href="https://tools.ietf.org/html/rfc5280#page-17">RFC 5280, section
4.1</a>, an extension is defined:</p>

<pre><code>Extension ::= SEQUENCE {
extnID OBJECT IDENTIFIER,
critical BOOLEAN DEFAULT FALSE,
extnValue OCTET STRING
— contains the DER encoding of an ASN.1 value
— corresponding to the extension type identified
— by extnID
}
</code></pre>

<p>We&rsquo;ve found the <code>extnID</code>. The &ldquo;critical&rdquo; field is omitted because it has the
default value (false). Next up is the <code>extnValue</code>. This has the type
<code>OCTET STRING</code>, which has the tag &ldquo;0x04&rdquo;. <code>OCTET STRING</code> means &ldquo;here&rsquo;s
a bunch of bytes!&rdquo; In this case, as described by the spec, those bytes
happen to contain more DER. This is a fairly common pattern in X.509
to deal with parameterized data. For instance, this allows defining a
structure for extensions without knowing ahead of time all the structures
that a future extension might want to carry in its value. If you&rsquo;re a C
programmer, think of it as a <code>void*</code> for data structures. If you prefer Go,
think of it as an <code>interface{}</code>.</p>

<p>Here&rsquo;s that <code>extnValue</code>:</p>

<pre><code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
</code></pre>

<p>That&rsquo;s tag &ldquo;0x04&rdquo;, meaning <code>OCTET STRING</code>, followed by &ldquo;0x81 0xF5&rdquo;, meaning
&ldquo;this string is 245 bytes long&rdquo; (the 0x81 prefix is part of <a href="#variable-length">variable length
number encoding</a>).</p>

<p>According to <a href="https://tools.ietf.org/html/rfc6962#section-3.3">RFC 6962, section
3.3</a>, &ldquo;obtained SCTs
can be directly embedded in the final certificate, by encoding the
SignedCertificateTimestampList structure as an ASN.1 <code>OCTET STRING</code>
and inserting the resulting data in the TBSCertificate as an X.509v3
certificate extension&rdquo;</p>

<p>So, we have an <code>OCTET STRING</code>, all&rsquo;s good, right? Except if you remove the
tag and length from extnValue to get its value, you&rsquo;re left with:</p>

<pre><code>04 81 F2 00F0007500DB74AFEEC…
</code></pre>

<p>There&rsquo;s that &ldquo;0x04&rdquo; tag again, but with a shorter length. Why
do we nest one <code>OCTET STRING</code> inside another? It&rsquo;s because the
contents of extnValue are required by RFC 5280 to be valid DER, but a
SignedCertificateTimestampList is not encoded using DER (more on that
in a minute). So, by RFC 6962, a SignedCertificateTimestampList is wrapped in an
<code>OCTET STRING</code>, which is wrapped in another <code>OCTET STRING</code> (the extnValue).</p>

<p>Once we decode that second <code>OCTET STRING</code>, we&rsquo;re left with the contents:</p>

<pre><code>00F0007500DB74AFEEC…
</code></pre>

<p>&ldquo;0x00&rdquo; isn&rsquo;t a valid tag in DER. What is this? It&rsquo;s TLS encoding. This is
defined in <a href="https://tools.ietf.org/html/rfc5246#section-4">RFC 5246, section 4</a>
(the TLS 1.2 RFC). TLS encoding, like ASN.1, has both a way to define data
structures and a way to encode those structures. TLS encoding differs
from DER in that there are no tags, and lengths are only encoded when necessary for
variable-length arrays. Within an encoded structure, the type of a field is determined by
its position, rather than by a tag. This means that TLS-encoded structures are
more compact than DER structures, but also that they can&rsquo;t be processed without
knowing the corresponding schema. For instance, here&rsquo;s the top-level schema from
<a href="https://tools.ietf.org/html/rfc6962#section-3.3">RFC 6962, section 3.3</a>:</p>

<pre><code> The contents of the ASN.1 OCTET STRING embedded in an OCSP extension
or X509v3 certificate extension are as follows:

opaque SerializedSCT&lt;1..2^16-1&gt;;

struct {
SerializedSCT sct_list &lt;1..2^16-1&gt;;
} SignedCertificateTimestampList;

Here, &quot;SerializedSCT&quot; is an opaque byte string that contains the
serialized TLS structure.
</code></pre>

<p>Right away, we&rsquo;ve found one of those variable-length arrays. The length of such
an array (in bytes) is always represented by a length field just big enough to
hold the max array size. The max size of an <code>sct_list</code> is 65535 bytes, so the
length field is two bytes wide. Sure enough, those first two bytes are &ldquo;0x00
0xF0&rdquo;, or 240 in decimal. In other words, this <code>sct_list</code> will have 240 bytes. We
don&rsquo;t yet know how many SCTs will be in it. That will become clear only by
continuing to parse the encoded data and seeing where each struct ends (spoiler
alert: there are two SCTs!).</p>

<p>Now we know the first SerializedSCT starts with <code>0075…</code>. SerializedSCT
is itself a variable-length field, this time containing <code>opaque</code> bytes (much like <code>OCTET STRING</code>
back in the ASN.1 world). Like SignedCertificateTimestampList, it has a max size
of 65535 bytes, so we pull off the first two bytes and discover that the first
SerializedSCT is 0x0075 (117 decimal) bytes long. Here&rsquo;s the whole thing, in
hex:</p>

<pre><code>00DB74AFEECB29ECB1FECA3E716D2CE5B9AABB36F7847183C75D9D4F37B61FBF64000001627313EB19000004030046304402207E1FCD1E9A2BD2A50A0C81E713033A0762340DA8F91EF27A48B3817640159CD30220659FE9F1D880E2E8F6B325BE9F18956D17C6CA8A6F2B12CB0F55FB70F759A419
</code></pre>

<p>This can be decoded using the TLS encoding struct defined in <a href="https://tools.ietf.org/html/rfc6962#page-13">RFC 6962, section
3.2</a>:</p>

<pre><code>enum { v1(0), (255) }
Version;

struct {
opaque key_id[32];
} LogID;

opaque CtExtensions&lt;0..2^16-1&gt;;

struct {
Version sct_version;
LogID id;
uint64 timestamp;
CtExtensions extensions;
digitally-signed struct {
Version sct_version;
SignatureType signature_type = certificate_timestamp;
uint64 timestamp;
LogEntryType entry_type;
select(entry_type) {
case x509_entry: ASN.1Cert;
case precert_entry: PreCert;
} signed_entry;
CtExtensions extensions;
};
} SignedCertificateTimestamp;
</code></pre>

<p>Breaking that down:</p>

<pre><code># Version sct_version v1(0)
00
# LogID id (aka opaque key_id[32])
DB74AFEECB29ECB1FECA3E716D2CE5B9AABB36F7847183C75D9D4F37B61FBF64
# uint64 timestamp (milliseconds since the epoch)
000001627313EB19
# CtExtensions extensions (zero-length array)
0000
# digitally-signed struct
04030046304402207E1FCD1E9A2BD2A50A0C81E713033A0762340DA8F91EF27A48B3817640159CD30220659FE9F1D880E2E8F6B325BE9F18956D17C6CA8A6F2B12CB0F55FB70F759A419
</code></pre>

<p>To understand the &ldquo;digitally-signed struct,&rdquo; we need to turn back to <a href="https://tools.ietf.org/html/rfc5246#section-4.7">RFC 5246,
section 4.7</a>. It says:</p>

<pre><code>A digitally-signed element is encoded as a struct DigitallySigned:

struct {
SignatureAndHashAlgorithm algorithm;
opaque signature&lt;0..2^16-1&gt;;
} DigitallySigned;
</code></pre>

<p>And in <a href="https://tools.ietf.org/html/rfc5246#section-7.4.1.4.1">section
7.4.1.4.1</a>:</p>

<pre><code>enum {
none(0), md5(1), sha1(2), sha224(3), sha256(4), sha384(5),
sha512(6), (255)
} HashAlgorithm;

enum { anonymous(0), rsa(1), dsa(2), ecdsa(3), (255) }
SignatureAlgorithm;

struct {
HashAlgorithm hash;
SignatureAlgorithm signature;
} SignatureAndHashAlgorithm;
</code></pre>

<p>We have &ldquo;0x0403&rdquo;, which corresponds to sha256(4) and ecdsa(3). The next two
bytes, &ldquo;0x0046&rdquo;, tell us the length of the &ldquo;opaque signature&rdquo; field, 70 bytes in
decimal. To decode the signature, we reference <a href="https://tools.ietf.org/html/rfc4492#page-20">RFC 4492 section
5.4</a>, which says:</p>

<pre><code>The digitally-signed element is encoded as an opaque vector &lt;0..2^16-1&gt;, the
contents of which are the DER encoding corresponding to the
following ASN.1 notation.

Ecdsa-Sig-Value ::= SEQUENCE {
r INTEGER,
s INTEGER
}
</code></pre>

<p>Having dived through two layers of TLS encoding, we are now back in ASN.1 land!
We
<a href="https://lapo.it/asn1js/#304402207E1FCD1E9A2BD2A50A0C81E713033A0762340DA8F91EF27A48B3817640159CD30220659FE9F1D880E2E8F6B325BE9F18956D17C6CA8A6F2B12CB0F55FB70F759A419">decode</a>
the remaining bytes into a SEQUENCE containing two INTEGERS. And we&rsquo;re done! Here&rsquo;s the whole
extension decoded:</p>

<pre><code># Extension SEQUENCE – RFC 5280
30
# length 0x0104 bytes (260 decimal)
820104
# OBJECT IDENTIFIER
06
# length 0x0A bytes (10 decimal)
0A
# value (1.3.6.1.4.1.11129.2.4.2)
2B06010401D679020402
# OCTET STRING
04
# length 0xF5 bytes (245 decimal)
81F5
# OCTET STRING (embedded) – RFC 6962
04
# length 0xF2 bytes (242 decimal)
81F2
# Beginning of TLS encoded SignedCertificateTimestampList – RFC 5246 / 6962
# length 0xF0 bytes
00F0
# opaque SerializedSCT&lt;1..2^16-1&gt;
# length 0x75 bytes
0075
# Version sct_version v1(0)
00
# LogID id (aka opaque key_id[32])
DB74AFEECB29ECB1FECA3E716D2CE5B9AABB36F7847183C75D9D4F37B61FBF64
# uint64 timestamp (milliseconds since the epoch)
000001627313EB19
# CtExtensions extensions (zero-length array)
0000
# digitally-signed struct – RFC 5426
# SignatureAndHashAlgorithm (ecdsa-sha256)
0403
# opaque signature&lt;0..2^16-1&gt;;
# length 0x0046
0046
# DER-encoded Ecdsa-Sig-Value – RFC 4492
30 # SEQUENCE
44 # length 0x44 bytes
02 # r INTEGER
20 # length 0x20 bytes
# value
7E1FCD1E9A2BD2A50A0C81E713033A0762340DA8F91EF27A48B3817640159CD3
02 # s INTEGER
20 # length 0x20 bytes
# value
659FE9F1D880E2E8F6B325BE9F18956D17C6CA8A6F2B12CB0F55FB70F759A419
# opaque SerializedSCT&lt;1..2^16-1&gt;
# length 0x77 bytes
0077
# Version sct_version v1(0)
00
# LogID id (aka opaque key_id[32])
293C519654C83965BAAA50FC5807D4B76FBF587A2972DCA4C30CF4E54547F478
# uint64 timestamp (milliseconds since the epoch)
000001627313EB2A
# CtExtensions extensions (zero-length array)
0000
# digitally-signed struct – RFC 5426
# SignatureAndHashAlgorithm (ecdsa-sha256)
0403
# opaque signature&lt;0..2^16-1&gt;;
# length 0x0048
0048
# DER-encoded Ecdsa-Sig-Value – RFC 4492
30 # SEQUENCE
46 # length 0x46 bytes
02 # r INTEGER
21 # length 0x21 bytes
# value
00AB72F1E4D6223EF87FC68491C208D29D4D57EBF47588BB7544D32F9537E2CEC1
02 # s INTEGER
21 # length 0x21 bytes
# value
008AFFC40CC6C4E3B24578DADE4F815ECBCE2D57A579342119A1E65BC7E5E69CE2
</code></pre>

<p>One surprising thing you might notice: In the first SCT, <code>r</code> and <code>s</code> are twenty
bytes long. In the second SCT, they are both twenty-one bytes long, and have a
leading zero. Integers in DER are two&rsquo;s complement, so if the leftmost bit is
set, they are interpreted as negative. Since <code>r</code> and <code>s</code> are positive, if the
leftmost bit would be a 1, an extra byte has to be added so that the leftmost
bit can be 0.</p>

<p>This is a little taste of what goes into encoding a certificate. I hope it was
informative! If you&rsquo;d like to learn more, I recommend &ldquo;<a href="http://luca.ntop.org/Teaching/Appunti/asn1.html">A Layman&rsquo;s Guide to a
Subset of ASN.1, BER, and DER</a>.&rdquo;</p>

<p><a name="poison"></a>Footnote 1: A &ldquo;poison extension&rdquo; is defined by <a href="https://tools.ietf.org/html/rfc6962#section-3.1">RFC 6962
section 3.1</a>:</p>

<pre><code>The Precertificate is constructed from the certificate to be issued by adding a special
critical poison extension (OID `1.3.6.1.4.1.11129.2.4.3`, whose
extnValue OCTET STRING contains ASN.1 NULL data (0x05 0x00))
</code></pre>

<p>In other words, it&rsquo;s an empty extension whose only purpose is to ensure that
certificate processors will not accept precertificates as valid certificates. The
specification ensures this by setting the &ldquo;critical&rdquo; bit on the extension, which
ensures that code that doesn&rsquo;t recognize the extension will reject the whole
certificate. Code that does recognize the extension specifically as poison
will also reject the certificate.</p>

<p><a name="variable-length"></a>Footnote 2: Lengths from 0-127 are represented by
a single byte (short form). To express longer lengths, more bytes are used (long form).
The high bit (0x80) on the first byte is set to distinguish long form from short
form. The remaining bits are used to express how many more bytes to read for the
length. For instance, 0x81F5 means &ldquo;this is long form because the length is
greater than 127, but there&rsquo;s still only one byte of length (0xF5) to decode.&rdquo;</p>