Tag Archives: The Mechanic

Augmented-reality projection lamp with Raspberry Pi and Android Things

Post Syndicated from Helen Lynn original https://www.raspberrypi.org/blog/augmented-reality-projector/

If your day has been a little fraught so far, watch this video. It opens with a tableau of methodically laid-out components and then shows them soldered, screwed, and slotted neatly into place. Everything fits perfectly; nothing needs percussive adjustment. Then it shows us glimpses of an AR future just like the one promised in the less dystopian comics and TV programmes of my 1980s childhood. It is all very soothing, and exactly what I needed.

Android Things – Lantern

Transform any surface into mixed-reality using Raspberry Pi, a laser projector, and Android Things. Android Experiments – http://experiments.withgoogle.com/android/lantern Lantern project site – http://nordprojects.co/lantern check below to make your own ↓↓↓ Get the code – https://github.com/nordprojects/lantern Build the lamp – https://www.hackster.io/nord-projects/lantern-9f0c28

Creating augmented reality with projection

We’ve seen plenty of Raspberry Pi IoT builds that are smart devices for the home; they add computing power to things like lights, door locks, or toasters to make these objects interact with humans and with their environment in new ways. Nord ProjectsLantern takes a different approach. In their words, it:

imagines a future where projections are used to present ambient information, and relevant UI within everyday objects. Point it at a clock to show your appointments, or point to speaker to display the currently playing song. Unlike a screen, when Lantern’s projections are no longer needed, they simply fade away.

Lantern is set up so that you can connect your wireless device to it using Google Nearby. This means there’s no need to create an account before you can dive into augmented reality.

Lantern Raspberry Pi powered projector lamp

Your own open-source AR lamp

Nord Projects collaborated on Lantern with Google’s Android Things team. They’ve made it fully open-source, so you can find the code on GitHub and also download their parts list, which includes a Pi, an IKEA lamp, an accelerometer, and a laser projector. Build instructions are at hackster.io and on GitHub.

This is a particularly clear tutorial, very well illustrated with photos and GIFs, and once you’ve sourced and 3D-printed all of the components, you shouldn’t need a whole lot of experience to put everything together successfully. Since everything is open-source, though, if you want to adapt it — for example, if you’d like to source a less costly projector than the snazzy one used here — you can do that too.

components of Lantern Raspberry Pi powered augmented reality projector lamp

The instructions walk you through the mechanical build and the wiring, as well as installing Android Things and Nord Projects’ custom software on the Raspberry Pi. Once you’ve set everything up, an accelerometer connected to the Pi’s GPIO pins lets the lamp know which surface it is pointing at. A companion app on your mobile device lets you choose from the mini apps that work on that surface to select the projection you want.

The designers are making several mini apps available for Lantern, including the charmingly named Space Porthole: this uses Processing and your local longitude and latitude to project onto your ceiling the stars you’d see if you punched a hole through to the sky, if it were night time, and clear weather. Wouldn’t you rather look at that than deal with the ant problem in your kitchen or tackle your GitHub notifications?

What would you like to project onto your living environment? Let us know in the comments!

The post Augmented-reality projection lamp with Raspberry Pi and Android Things appeared first on Raspberry Pi.

What John Oliver gets wrong about Bitcoin

Post Syndicated from Robert Graham original http://blog.erratasec.com/2018/03/what-john-oliver-gets-wrong-about.html

John Oliver covered bitcoin/cryptocurrencies last night. I thought I’d describe a bunch of things he gets wrong.

How Bitcoin works

Nowhere in the show does it describe what Bitcoin is and how it works.
Discussions should always start with Satoshi Nakamoto’s original paper. The thing Satoshi points out is that there is an important cost to normal transactions, namely, the entire legal system designed to protect you against fraud, such as the way you can reverse the transactions on your credit card if it gets stolen. The point of Bitcoin is that there is no way to reverse a charge. A transaction is done via cryptography: to transfer money to me, you decrypt it with your secret key and encrypt it with mine, handing ownership over to me with no third party involved that can reverse the transaction, and essentially no overhead.
All the rest of the stuff, like the decentralized blockchain and mining, is all about making that work.
Bitcoin crazies forget about the original genesis of Bitcoin. For example, they talk about adding features to stop fraud, reversing transactions, and having a central authority that manages that. This misses the point, because the existing electronic banking system already does that, and does a better job at it than cryptocurrencies ever can. If you want to mock cryptocurrencies, talk about the “DAO”, which did exactly that — and collapsed in a big fraudulent scheme where insiders made money and outsiders didn’t.
Sticking to Satoshi’s original ideas are a lot better than trying to repeat how the crazy fringe activists define Bitcoin.

How does any money have value?

Oliver’s answer is currencies have value because people agree that they have value, like how they agree a Beanie Baby is worth $15,000.
This is wrong. A better way of asking the question why the value of money changes. The dollar has been losing roughly 2% of its value each year for decades. This is called “inflation”, as the dollar loses value, it takes more dollars to buy things, which means the price of things (in dollars) goes up, and employers have to pay us more dollars so that we can buy the same amount of things.
The reason the value of the dollar changes is largely because the Federal Reserve manages the supply of dollars, using the same law of Supply and Demand. As you know, if a supply decreases (like oil), then the price goes up, or if the supply of something increases, the price goes down. The Fed manages money the same way: when prices rise (the dollar is worth less), the Fed reduces the supply of dollars, causing it to be worth more. Conversely, if prices fall (or don’t rise fast enough), the Fed increases supply, so that the dollar is worth less.
The reason money follows the law of Supply and Demand is because people use money, they consume it like they do other goods and services, like gasoline, tax preparation, food, dance lessons, and so forth. It’s not like a fine art painting, a stamp collection or a Beanie Baby — money is a product. It’s just that people have a hard time thinking of it as a consumer product since, in their experience, money is what they use to buy consumer products. But it’s a symmetric operation: when you buy gasoline with dollars, you are actually selling dollars in exchange for gasoline. That you call one side in this transaction “money” and the other “goods” is purely arbitrary, you call gasoline money and dollars the good that is being bought and sold for gasoline.
The reason dollars is a product is because trying to use gasoline as money is a pain in the neck. Storing it and exchanging it is difficult. Goods like this do become money, such as famously how prisons often use cigarettes as a medium of exchange, even for non-smokers, but it has to be a good that is fungible, storable, and easily exchanged. Dollars are the most fungible, the most storable, and the easiest exchanged, so has the most value as “money”. Sure, the mechanic can fix the farmers car for three chickens instead, but most of the time, both parties in the transaction would rather exchange the same value using dollars than chickens.
So the value of dollars is not like the value of Beanie Babies, which people might buy for $15,000, which changes purely on the whims of investors. Instead, a dollar is like gasoline, which obey the law of Supply and Demand.
This brings us back to the question of where Bitcoin gets its value. While Bitcoin is indeed used like dollars to buy things, that’s only a tiny use of the currency, so therefore it’s value isn’t determined by Supply and Demand. Instead, the value of Bitcoin is a lot like Beanie Babies, obeying the laws of investments. So in this respect, Oliver is right about where the value of Bitcoin comes, but wrong about where the value of dollars comes from.

Why Bitcoin conference didn’t take Bitcoin

John Oliver points out the irony of a Bitcoin conference that stopped accepting payments in Bitcoin for tickets.
The biggest reason for this is because Bitcoin has become so popular that transaction fees have gone up. Instead of being proof of failure, it’s proof of popularity. What John Oliver is saying is the old joke that nobody goes to that popular restaurant anymore because it’s too crowded and you can’t get a reservation.
Moreover, the point of Bitcoin is not to replace everyday currencies for everyday transactions. If you read Satoshi Nakamoto’s whitepaper, it’s only goal is to replace certain types of transactions, like purely electronic transactions where electronic goods and services are being exchanged. Where real-life goods/services are being exchanged, existing currencies work just fine. It’s only the crazy activists who claim Bitcoin will eventually replace real world currencies — the saner people see it co-existing with real-world currencies, each with a different value to consumers.

Turning a McNugget back into a chicken

John Oliver uses the metaphor of turning a that while you can process a chicken into McNuggets, you can’t reverse the process. It’s a funny metaphor.
But it’s not clear what the heck this metaphor is trying explain. That’s not a metaphor for the blockchain, but a metaphor for a “cryptographic hash”, where each block is a chicken, and the McNugget is the signature for the block (well, the block plus the signature of the last block, forming a chain).
Even then that metaphor as problems. The McNugget produced from each chicken must be unique to that chicken, for the metaphor to accurately describe a cryptographic hash. You can therefore identify the original chicken simply by looking at the McNugget. A slight change in the original chicken, like losing a feather, results in a completely different McNugget. Thus, nuggets can be used to tell if the original chicken has changed.
This then leads to the key property of the blockchain, it is unalterable. You can’t go back and change any of the blocks of data, because the fingerprints, the nuggets, will also change, and break the nugget chain.
The point is that while John Oliver is laughing at a silly metaphor to explain the blockchain becuase he totally misses the point of the metaphor.
Oliver rightly says “don’t worry if you don’t understand it — most people don’t”, but that includes the big companies that John Oliver name. Some companies do get it, and are producing reasonable things (like JP Morgan, by all accounts), but some don’t. IBM and other big consultancies are charging companies millions of dollars to consult with them on block chain products where nobody involved, the customer or the consultancy, actually understand any of it. That doesn’t stop them from happily charging customers on one side and happily spending money on the other.
Thus, rather than Oliver explaining the problem, he’s just being part of the problem. His explanation of blockchain left you dumber than before.

ICO’s

John Oliver mocks the Brave ICO ($35 million in 30 seconds), claiming it’s all driven by YouTube personalities and people who aren’t looking at the fundamentals.
And while this is true, most ICOs are bunk, the  Brave ICO actually had a business model behind it. Brave is a Chrome-like web-browser whose distinguishing feature is that it protects your privacy from advertisers. If you don’t use Brave or a browser with an ad block extension, you have no idea how bad things are for you. However, this presents a problem for websites that fund themselves via advertisements, which is most of them, because visitors no longer see ads. Brave has a fix for this. Most people wouldn’t mind supporting the websites they visit often, like the New York Times. That’s where the Brave ICO “token” comes in: it’s not simply stock in Brave, but a token for micropayments to websites. Users buy tokens, then use them for micropayments to websites like New York Times. The New York Times then sells the tokens back to the market for dollars. The buying and selling of tokens happens without a centralized middleman.
This is still all speculative, of course, and it remains to be seen how successful Brave will be, but it’s a serious effort. It has well respected VC behind the company, a well-respected founder (despite the fact he invented JavaScript), and well-respected employees. It’s not a scam, it’s a legitimate venture.

How to you make money from Bitcoin?

The last part of the show is dedicated to describing all the scam out there, advising people to be careful, and to be “responsible”. This is garbage.
It’s like my simple two step process to making lots of money via Bitcoin: (1) buy when the price is low, and (2) sell when the price is high. My advice is correct, of course, but useless. Same as “be careful” and “invest responsibly”.
The truth about investing in cryptocurrencies is “don’t”. The only responsible way to invest is to buy low-overhead market index funds and hold for retirement. No, you won’t get super rich doing this, but anything other than this is irresponsible gambling.
It’s a hard lesson to learn, because everyone is telling you the opposite. The entire channel CNBC is devoted to day traders, who buy and sell stocks at a high rate based on the same principle as a ponzi scheme, basing their judgment not on the fundamentals (like long term dividends) but animal spirits of whatever stock is hot or cold at the moment. This is the same reason people buy or sell Bitcoin, not because they can describe the fundamental value, but because they believe in a bigger fool down the road who will buy it for even more.
For things like Bitcoin, the trick to making money is to have bought it over 7 years ago when it was essentially worthless, except to nerds who were into that sort of thing. It’s the same tick to making a lot of money in Magic: The Gathering trading cards, which nerds bought decades ago which are worth a ton of money now. Or, to have bought Apple stock back in 2009 when the iPhone was new, when nerds could understand the potential of real Internet access and apps that Wall Street could not.
That was my strategy: be a nerd, who gets into things. I’ve made a good amount of money on all these things because as a nerd, I was into Magic: The Gathering, Bitcoin, and the iPhone before anybody else was, and bought in at the point where these things were essentially valueless.
At this point with cryptocurrencies, with the non-nerds now flooding the market, there little chance of making it rich. The lottery is probably a better bet. Instead, if you want to make money, become a nerd, obsess about a thing, understand a thing when its new, and cash out once the rest of the market figures it out. That might be Brave, for example, but buy into it because you’ve spent the last year studying the browser advertisement ecosystem, the market’s willingness to pay for content, and how their Basic Attention Token delivers value to websites — not because you want in on the ICO craze.

Conclusion

John Oliver spends 25 minutes explaining Bitcoin, Cryptocurrencies, and the Blockchain to you. Sure, it’s funny, but it leaves you worse off than when it started. It admits they “simplify” the explanation, but they simplified it so much to the point where they removed all useful information.

Смешно-несмешно

Post Syndicated from Антония original http://dni.li/2017/07/10/bornacrime/

Четеш си кротко Born a Crime на Trevor Noah, кискаш се под мустак, разбира се, от време на време омфгираш как животът в апартейден ЮАР е хем много различен от всичко познато, хем някак доста приличащ с абсурдността си на някогашните наши соц реалии… и стигаш до:

To this day I hate secondhand cars. Almost everything that’s ever gone wrong in my life I can trace back to a secondhand car. Secondhand cars made me get detention for being late for school. Secondhand cars left us hitchhiking on the side of the freeway. A secondhand car was also the reason my mom got married. If it hadn’t been for the Volkswagen that didn’t work, we never would have looked for the mechanic who became the husband who became the stepfather who became the man who tortured us for years and put a bullet in the back of my mother’s head—I’ll take the new car with the warranty every time.

… където усмивката ти замръзва на устните, оставяш рийдъра настрана и някак не ти се чете вече. И не ти е смешно.

Under the Hood of Server-Side Encryption for Amazon Kinesis Streams

Post Syndicated from Damian Wylie original https://aws.amazon.com/blogs/big-data/under-the-hood-of-server-side-encryption-for-amazon-kinesis-streams/

Customers are using Amazon Kinesis Streams to ingest, process, and deliver data in real time from millions of devices or applications. Use cases for Kinesis Streams vary, but a few common ones include IoT data ingestion and analytics, log processing, clickstream analytics, and enterprise data bus architectures.

Within milliseconds of data arrival, applications (KCL, Apache Spark, AWS Lambda, Amazon Kinesis Analytics) attached to a stream are continuously mining value or delivering data to downstream destinations. Customers are then scaling their streams elastically to match demand. They pay incrementally for the resources that they need, while taking advantage of a fully managed, serverless streaming data service that allows them to focus on adding value closer to their customers.

These benefits are great; however, AWS learned that many customers could not take advantage of Kinesis Streams unless their data-at-rest within a stream was encrypted. Many customers did not want to manage encryption on their own, so they asked for a fully managed, automatic, server-side encryption mechanism leveraging centralized AWS Key Management Service (AWS KMS) customer master keys (CMK).

Motivated by this feedback, AWS added another fully managed, low cost aspect to Kinesis Streams by delivering server-side encryption via KMS managed encryption keys (SSE-KMS) in the following regions:

  • US East (N. Virginia)
  • US West (Oregon)
  • US West (N. California)
  • EU (Ireland)
  • Asia Pacific (Singapore)
  • Asia Pacific (Tokyo)

In this post, I cover the mechanics of the Kinesis Streams server-side encryption feature. I also share a few best practices and considerations so that you can get started quickly.

Understanding the mechanics

The following section walks you through how Kinesis Streams uses CMKs to encrypt a message in the PutRecord or PutRecords path before it is propagated to the Kinesis Streams storage layer, and then decrypt it in the GetRecords path after it has been retrieved from the storage layer.

When server-side encryption is enabled—which takes just a few clicks in the console—the partition key and payload for every incoming record is encrypted automatically as it’s flowing into Kinesis Streams, using the selected CMK. When data is at rest within a stream, it’s encrypted.

When records are retrieved through a GetRecords request from the encrypted stream, they are decrypted automatically as they are flowing out of the service. That means your Kinesis Streams producers and consumers do not need to be aware of encryption. You have a fully managed data encryption feature at your fingertips, which can be enabled within seconds.

AWS also makes it easy to audit the application of server-side encryption. You can use the AWS Management Console for instant stream-level verification; the responses from PutRecord, PutRecords, and getRecords; or AWS CloudTrail.

Calling PutRecord or PutRecords

When server-side encryption is enabled for a particular stream, Kinesis Streams and KMS perform the following actions when your applications call PutRecord or PutRecords on a stream with server-side encryption enabled. The Amazon Kinesis Producer Library (KPL) uses PutRecords.

 

  1. Data is sent from a customer’s producer (client) to a Kinesis stream using TLS via HTTPS. Data in transit to a stream is encrypted by default.
  2. After data is received, it is momentarily stored in RAM within a front-end proxy layer.
  3. Kinesis Streams authenticates the producer, then impersonates the producer to request input keying material from KMS.
  4. KMS creates key material, encrypts it by using CMK, and sends both the plaintext and encrypted key material to the service, encrypted with TLS.
  5. The client uses the plaintext key material to derive data encryption keys (data keys) that are unique per-record.
  6. The client encrypts the payload and partition key using the data key in RAM within the front-end proxy layer and removes the plaintext data key from memory.
  7. The client appends the encrypted key material to the encrypted data.
  8. The plaintext key material is securely cached in memory within the front-end layer for reuse, until it expires after 5 minutes.
  9. The client delivers the encrypted message to a back-end store where it is stored at rest and fetchable by an authorized consumer through a GetRecords The Amazon Kinesis Client Library (KCL) calls GetRecords to retrieve records from a stream.

Calling getRecords

Kinesis Streams and KMS perform the following actions when your applications call GetRecords on a server-side encrypted stream.

 

  1. When a GeRecords call is made, the front-end proxy layer retrieves the encrypted record from its back-end store.
  2. The consumer (client) makes a request to KMS using a token generated by the customer’s request. KMS authorizes it.
  3. The client requests that KMS decrypt the encrypted key material.
  4. KMS decrypts the encrypted key material and sends the plaintext key material to the client.
  5. Kinesis Streams derives the per-record data keys from the decrypted key material.
  6. If the calling application is authorized, the client decrypts the payload and removes the plaintext data key from memory.
  7. The client delivers the payload over TLS and HTTPS to the consumer, requesting the records. Data in transit to a consumer is encrypted by default.

Verifying server-side encryption

Auditors or administrators often ask for proof that server-side encryption was or is enabled. Here are a few ways to do this.

To check if encryption is enabled now for your streams:

  • Use the AWS Management Console or the DescribeStream API operation. You can also see what CMK is being used for encryption.
  • See encryption in action by looking at responses from PutRecord, PutRecords, or GetRecords When encryption is enabled, the encryptionType parameter is set to “KMS”. If encryption is not enabled, encryptionType is not included in the response.

Sample PutRecord response

{
    "SequenceNumber": "49573959617140871741560010162505906306417380215064887298",
    "ShardId": "shardId-000000000000",
    "EncryptionType": "KMS"
}

Sample GetRecords response

{
    "Records": [
        {
            "Data": "aGVsbG8gd29ybGQ=", 
            "PartitionKey": "test", 
            "ApproximateArrivalTimestamp": 1498292565.825, 
            "EncryptionType": "KMS", 
            "SequenceNumber": "495735762417140871741560010162505906306417380215064887298"
        }, 
        {
            "Data": "ZnJvZG8gbGl2ZXMK", 
            "PartitionKey": "3d0d9301-3c30-4c48-a9a8-e485b2982b28", 
            "ApproximateArrivalTimestamp": 1498292801.747, 
            "EncryptionType": "KMS", 
            "SequenceNumber": "49573959617140871741560010162507115232237011062036103170"
        }
    ], 
    "NextShardIterator": "AAAAAAAAAAEvFypHZDx/4bJVAS34puwdiNcwssKqbh/XhRK7HSYRq3RS+YXJnVKJ8j0gQUt94bONdqQYHk9X9JHgefMUDKzDzndy5WbZWO4CS3hRdMdrbmJ/9KoR4lOfZvqTLt6JWQjDqXv0IaKs06/LHYcEA3oPcyQLOTJHdJl2EzplCTZnn/U295ovxvqF9g9DY8y2nVoMkdFLmdcEMVXjhCDKiRIt", 
    "MillisBehindLatest": 0
}

To check if encryption was enabled, use CloudTrail, which logs the StartStreamEncryption() and StopStreamEncryption() API calls made against a particular stream.

Getting started

It’s very easy to enable, disable, or modify server-side encryption for a particular stream.

  1. In the Kinesis Streams console, select a stream and choose Details.
  2. Select a CMK and select Enabled.
  3. Choose Save.

You can enable encryption only for a live stream, not upon stream creation.  Follow the same process to disable a stream. To use a different CMK, select it and choose Save.

Each of these tasks can also be accomplished using the StartStreamEncryption and StopStreamEncryption API operations.

Considerations

There are a few considerations you should be aware of when using server-side encryption for Kinesis Streams:

  • Permissions
  • Costs
  • Performance

Permissions

One benefit of using the “(Default) aws/kinesis” AWS managed key is that every producer and consumer with permissions to call PutRecord, PutRecords, or GetRecords inherits the right permissions over the “(Default) aws/kinesis” key automatically.

However, this is not necessarily the same case for a CMK. Kinesis Streams producers and consumers do not need to be aware of encryption. However, if you enable encryption using a custom master key but a producer or consumer doesn’t have IAM permissions to use it, PutRecord, PutRecords, or GetRecords requests fail.

This is a great security feature. On the other hand, it can effectively lead to data loss if you inadvertently apply a custom master key that restricts producers and consumers from interacting from the Kinesis stream. Take precautions when applying a custom master key. For more information about the minimum IAM permissions required for producers and consumers interacting with an encrypted stream, see Using Server-Side Encryption.

Costs

When you apply server-side encryption, you are subject to KMS API usage and key costs. Unlike custom KMS master keys, the “(Default) aws/kinesis” CMK is offered free of charge. However, you still need to pay for the API usage costs that Kinesis Streams incurs on your behalf.

API usage costs apply for every CMK, including custom ones. Kinesis Streams calls KMS approximately every 5 minutes when it is rotating the data key. In a 30-day month, the total cost of KMS API calls initiated by a Kinesis stream should be less than a few dollars.

Performance

During testing, AWS discovered that there was a slight increase (typically 0.2 millisecond or less per record) with put and get record latencies due to the additional overhead of encryption.

If you have questions or suggestions, please comment below.