Tag Archives: utilities

Getting Rid of Your Mac? Here’s How to Securely Erase a Hard Drive or SSD

Post Syndicated from Roderick Bauer original https://www.backblaze.com/blog/how-to-wipe-a-mac-hard-drive/

erasing a hard drive and a solid state drive

What do I do with a Mac that still has personal data on it? Do I take out the disk drive and smash it? Do I sweep it with a really strong magnet? Is there a difference in how I handle a hard drive (HDD) versus a solid-state drive (SSD)? Well, taking a sledgehammer or projectile weapon to your old machine is certainly one way to make the data irretrievable, and it can be enormously cathartic as long as you follow appropriate safety and disposal protocols. But there are far less destructive ways to make sure your data is gone for good. Let me introduce you to secure erasing.

Which Type of Drive Do You Have?

Before we start, you need to know whether you have a HDD or a SSD. To find out, or at least to make sure, you click on the Apple menu and select “About this Mac.” Once there, select the “Storage” tab to see which type of drive is in your system.

The first example, below, shows a SATA Disk (HDD) in the system.

SATA HDD

In the next case, we see we have a Solid State SATA Drive (SSD), plus a Mac SuperDrive.

Mac storage dialog showing SSD

The third screen shot shows an SSD, as well. In this case it’s called “Flash Storage.”

Flash Storage

Make Sure You Have a Backup

Before you get started, you’ll want to make sure that any important data on your hard drive has moved somewhere else. OS X’s built-in Time Machine backup software is a good start, especially when paired with Backblaze. You can learn more about using Time Machine in our Mac Backup Guide.

With a local backup copy in hand and secure cloud storage, you know your data is always safe no matter what happens.

Once you’ve verified your data is backed up, roll up your sleeves and get to work. The key is OS X Recovery — a special part of the Mac operating system since OS X 10.7 “Lion.”

How to Wipe a Mac Hard Disk Drive (HDD)

NOTE: If you’re interested in wiping an SSD, see below.

    1. Make sure your Mac is turned off.
    2. Press the power button.
    3. Immediately hold down the command and R keys.
    4. Wait until the Apple logo appears.
    5. Select “Disk Utility” from the OS X Utilities list. Click Continue.
    6. Select the disk you’d like to erase by clicking on it in the sidebar.
    7. Click the Erase button.
    8. Click the Security Options button.
    9. The Security Options window includes a slider that enables you to determine how thoroughly you want to erase your hard drive.

There are four notches to that Security Options slider. “Fastest” is quick but insecure — data could potentially be rebuilt using a file recovery app. Moving that slider to the right introduces progressively more secure erasing. Disk Utility’s most secure level erases the information used to access the files on your disk, then writes zeroes across the disk surface seven times to help remove any trace of what was there. This setting conforms to the DoD 5220.22-M specification.

  1. Once you’ve selected the level of secure erasing you’re comfortable with, click the OK button.
  2. Click the Erase button to begin. Bear in mind that the more secure method you select, the longer it will take. The most secure methods can add hours to the process.

Once it’s done, the Mac’s hard drive will be clean as a whistle and ready for its next adventure: a fresh installation of OS X, being donated to a relative or a local charity, or just sent to an e-waste facility. Of course you can still drill a hole in your disk or smash it with a sledgehammer if it makes you happy, but now you know how to wipe the data from your old computer with much less ruckus.

The above instructions apply to older Macintoshes with HDDs. What do you do if you have an SSD?

Securely Erasing SSDs, and Why Not To

Most new Macs ship with solid state drives (SSDs). Only the iMac and Mac mini ship with regular hard drives anymore, and even those are available in pure SSD variants if you want.

If your Mac comes equipped with an SSD, Apple’s Disk Utility software won’t actually let you zero the hard drive.

Wait, what?

In a tech note posted to Apple’s own online knowledgebase, Apple explains that you don’t need to securely erase your Mac’s SSD:

With an SSD drive, Secure Erase and Erasing Free Space are not available in Disk Utility. These options are not needed for an SSD drive because a standard erase makes it difficult to recover data from an SSD.

In fact, some folks will tell you not to zero out the data on an SSD, since it can cause wear and tear on the memory cells that, over time, can affect its reliability. I don’t think that’s nearly as big an issue as it used to be — SSD reliability and longevity has improved.

If “Standard Erase” doesn’t quite make you feel comfortable that your data can’t be recovered, there are a couple of options.

FileVault Keeps Your Data Safe

One way to make sure that your SSD’s data remains secure is to use FileVault. FileVault is whole-disk encryption for the Mac. With FileVault engaged, you need a password to access the information on your hard drive. Without it, that data is encrypted.

There’s one potential downside of FileVault — if you lose your password or the encryption key, you’re screwed: You’re not getting your data back any time soon. Based on my experience working at a Mac repair shop, losing a FileVault key happens more frequently than it should.

When you first set up a new Mac, you’re given the option of turning FileVault on. If you don’t do it then, you can turn on FileVault at any time by clicking on your Mac’s System Preferences, clicking on Security & Privacy, and clicking on the FileVault tab. Be warned, however, that the initial encryption process can take hours, as will decryption if you ever need to turn FileVault off.

With FileVault turned on, you can restart your Mac into its Recovery System (by restarting the Mac while holding down the command and R keys) and erase the hard drive using Disk Utility, once you’ve unlocked it (by selecting the disk, clicking the File menu, and clicking Unlock). That deletes the FileVault key, which means any data on the drive is useless.

FileVault doesn’t impact the performance of most modern Macs, though I’d suggest only using it if your Mac has an SSD, not a conventional hard disk drive.

Securely Erasing Free Space on Your SSD

If you don’t want to take Apple’s word for it, if you’re not using FileVault, or if you just want to, there is a way to securely erase free space on your SSD. It’s a little more involved but it works.

Before we get into the nitty-gritty, let me state for the record that this really isn’t necessary to do, which is why Apple’s made it so hard to do. But if you’re set on it, you’ll need to use Apple’s Terminal app. Terminal provides you with command line interface access to the OS X operating system. Terminal lives in the Utilities folder, but you can access Terminal from the Mac’s Recovery System, as well. Once your Mac has booted into the Recovery partition, click the Utilities menu and select Terminal to launch it.

From a Terminal command line, type:

diskutil secureErase freespace VALUE /Volumes/DRIVE

That tells your Mac to securely erase the free space on your SSD. You’ll need to change VALUE to a number between 0 and 4. 0 is a single-pass run of zeroes; 1 is a single-pass run of random numbers; 2 is a 7-pass erase; 3 is a 35-pass erase; and 4 is a 3-pass erase. DRIVE should be changed to the name of your hard drive. To run a 7-pass erase of your SSD drive in “JohnB-Macbook”, you would enter the following:

diskutil secureErase freespace 2 /Volumes/JohnB-Macbook

And remember, if you used a space in the name of your Mac’s hard drive, you need to insert a leading backslash before the space. For example, to run a 35-pass erase on a hard drive called “Macintosh HD” you enter the following:

diskutil secureErase freespace 3 /Volumes/Macintosh\ HD

Something to remember is that the more extensive the erase procedure, the longer it will take.

When Erasing is Not Enough — How to Destroy a Drive

If you absolutely, positively need to be sure that all the data on a drive is irretrievable, see this Scientific American article (with contributions by Gleb Budman, Backblaze CEO), How to Destroy a Hard Drive — Permanently.

The post Getting Rid of Your Mac? Here’s How to Securely Erase a Hard Drive or SSD appeared first on Backblaze Blog | Cloud Storage & Cloud Backup.

Your Hard Drive Crashed — Get Working Again Fast with Backblaze

Post Syndicated from Roderick Bauer original https://www.backblaze.com/blog/how-to-recover-your-files-with-backblaze/

holding a hard drive and diagnostic tools
The worst thing for a computer user has happened. The hard drive on your computer crashed, or your computer is lost or completely unusable.

Fortunately, you’re a Backblaze customer with a current backup in the cloud. That’s great. The challenge is that you’ve got a presentation to make in just 48 hours and the document and materials you need for the presentation were on the hard drive that crashed.

Relax. Backblaze has your data (and your back). The question is, how do you get what you need to make that presentation deadline?

Here are some strategies you could use.

One — The first approach is to get back the presentation file and materials you need to meet your presentation deadline as quickly as possible. You can use another computer (maybe even your smartphone) to make that presentation.

Two — The second approach is to get your computer (or a new computer, if necessary) working again and restore all the files from your Backblaze backup.

Let’s start with Option One, which gets you back to work with just the files you need now as quickly as possible.

Option One — You’ve Got a Deadline and Just Need Your Files

Getting Back to Work Immediately

You want to get your computer working again as soon as possible, but perhaps your top priority is getting access to the files you need for your presentation. The computer can wait.

Find a Computer to Use

First of all. You’re going to need a computer to use. If you have another computer handy, you’re all set. If you don’t, you’re going to need one. Here are some ideas on where to find one:

  • Family and Friends
  • Work
  • Neighbors
  • Local library
  • Local school
  • Community or religious organization
  • Local computer shop
  • Online store

Laptop computer

If you have a smartphone that you can use to give your presentation or to print materials, that’s great. With the Backblaze app for iOS and Android, you can download files directly from your Backblaze account to your smartphone. You also have the option with your smartphone to email or share files from your Backblaze backup so you can use them elsewhere.

Laptop with smartphone

Download The File(s) You Need

Once you have the computer, you need to connect to your Backblaze backup through a web browser or the Backblaze smartphone app.

Backblaze Web Admin

Sign into your Backblaze account. You can download the files directly or use the share link to share files with yourself or someone else.

If you need step-by-step instructions on retrieving your files, see Restore the Files to the Drive section below. You also can find help at https://help.backblaze.com/hc/en-us/articles/217665888-How-to-Create-a-Restore-from-Your-Backblaze-Backup.

Smartphone App

If you have an iOS or Android smartphone, you can use the Backblaze app and retrieve the files you need. You then could view the file on your phone, use a smartphone app with the file, or email it to yourself or someone else.

Backblaze Smartphone app (iOS)

Backblaze Smartphone app (iOS)

Using one of the approaches above, you got your files back in time for your presentation. Way to go!

Now, the next step is to get the computer with the bad drive running again and restore all your files, or, if that computer is no longer usable, restore your Backblaze backup to a new computer.

Option Two — You Need a Working Computer Again

Getting the Computer with the Failed Drive Running Again (or a New Computer)

If the computer with the failed drive can’t be saved, then you’re going to need a new computer. A new computer likely will come with the operating system installed and ready to boot. If you’ve got a running computer and are ready to restore your files from Backblaze, you can skip forward to Restore the Files to the Drive.

If you need to replace the hard drive in your computer before you restore your files, you can continue reading.

Buy a New Hard Drive to Replace the Failed Drive

The hard drive is gone, so you’re going to need a new drive. If you have a computer or electronics store nearby, you could get one there. Another choice is to order a drive online and pay for one or two-day delivery. You have a few choices:

  1. Buy a hard drive of the same type and size you had
  2. Upgrade to a drive with more capacity
  3. Upgrade to an SSD. SSDs cost more but they are faster, more reliable, and less susceptible to jolts, magnetic fields, and other hazards that can affect a drive. Otherwise, they work the same as a hard disk drive (HDD) and most likely will work with the same connector.


Hard Disk Drive (HDD)Solid State Drive (SSD)

Hard Disk Drive (HDD)

Solid State Drive (SSD)


Be sure that the drive dimensions are compatible with where you’re going to install the drive in your computer, and the drive connector is compatible with your computer system (SATA, PCIe, etc.) Here’s some help.

Install the Drive

If you’re handy with computers, you can install the drive yourself. It’s not hard, and there are numerous videos on YouTube and elsewhere on how to do this. Just be sure to note how everything was connected so you can get everything connected and put back together correctly. Also, be sure that you discharge any static electricity from your body by touching something metallic before you handle anything inside the computer. If all this sounds like too much to handle, find a friend or a local computer store to help you.

Note:  If the drive that failed is a boot drive for your operating system (either Macintosh or Windows), you need to make sure that the drive is bootable and has the operating system files on it. You may need to reinstall from an operating system source disk or install files.

Restore the Files to the Drive

To start, you will need to sign in to the Backblaze website with your registered email address and password. Visit https://secure.backblaze.com/user_signin.htm to login.

Sign In to Your Backblaze Account

Selecting the Backup

Once logged in, you will be brought to the account Overview page. On this page, all of the computers registered for backup under your account are shown with some basic information about each. Select the backup from which you wish to restore data by using the appropriate “Restore” button.

Screenshot of Admin for Selecting the Type of Restore

Selecting the Type of Restore

Backblaze offers three different ways in which you can receive your restore data: downloadable ZIP file, USB flash drive, or USB hard drive. The downloadable ZIP restore option will create a ZIP file of the files you request that is made available for download for 7 days. ZIP restores do not have any additional cost and are a great option for individual files or small sets of data.

Depending on the speed of your internet connection to the Backblaze data center, downloadable restores may not always be the best option for restoring very large amounts of data. ZIP restores are limited to 500 GB per request and a maximum of 5 active requests can be submitted under a single account at any given time.

USB flash and hard drive restores are built with the data you request and then shipped to an address of your choosing via FedEx Overnight or FedEx Priority International. USB flash restores cost $99 and can contain up to 128 GB (110,000 MB of data) and USB hard drive restores cost $189 and can contain up to 4TB max (3,500,000 MB of data). Both include the cost of shipping.

You can return the ZIP drive within 30 days for a full refund with our Restore Return Refund Program, effectively making the process of restoring free, even with a shipped USB drive.

Screenshot of Admin for Selecting the Backup

Selecting Files for Restore

Using the left hand file viewer, navigate to the location of the files you wish to restore. You can use the disclosure triangles to see subfolders. Clicking on a folder name will display the folder’s files in the right hand file viewer. If you are attempting to restore files that have been deleted or are otherwise missing or files from a failed or disconnected secondary or external hard drive, you may need to change the time frame parameters.

Put checkmarks next to disks, files or folders you’d like to recover. Once you have selected the files and folders you wish to restore, select the “Continue with Restore” button above or below the file viewer. Backblaze will then build the restore via the option you select (ZIP or USB drive). You’ll receive an automated email notifying you when the ZIP restore has been built and is ready for download or when the USB restore drive ships.

If you are using the downloadable ZIP option, and the restore is over 2 GB, we highly recommend using the Backblaze Downloader for better speed and reliability. We have a guide on using the Backblaze Downloader for Mac OS X or for Windows.

For additional assistance, visit our help files at https://help.backblaze.com/hc/en-us/articles/217665888-How-to-Create-a-Restore-from-Your-Backblaze-Backup

Screenshot of Admin for Selecting Files for Restore

Extracting the ZIP

Recent versions of both macOS and Windows have built-in capability to extract files from a ZIP archive. If the built-in capabilities aren’t working for you, you can find additional utilities for Macintosh and Windows.

Reactivating your Backblaze Account

Now that you’ve got a working computer again, you’re going to need to reinstall Backblaze Backup (if it’s not on the system already) and connect with your existing account. Start by downloading and reinstalling Backblaze.

If you’ve restored the files from your Backblaze Backup to your new computer or drive, you don’t want to have to reupload the same files again to your Backblaze backup. To let Backblaze know that this computer is on the same account and has the same files, you need to use “Inherit Backup State.” See https://help.backblaze.com/hc/en-us/articles/217666358-Inherit-Backup-State

Screenshot of Admin for Inherit Backup State

That’s It

You should be all set, either with the files you needed for your presentation, or with a restored computer that is again ready to do productive work.

We hope your presentation wowed ’em.

If you have any additional questions on restoring from a Backblaze backup, please ask away in the comments. Also, be sure to check out our help resources at https://www.backblaze.com/help.html.

The post Your Hard Drive Crashed — Get Working Again Fast with Backblaze appeared first on Backblaze Blog | Cloud Storage & Cloud Backup.

Amazon Redshift – 2017 Recap

Post Syndicated from Larry Heathcote original https://aws.amazon.com/blogs/big-data/amazon-redshift-2017-recap/

We have been busy adding new features and capabilities to Amazon Redshift, and we wanted to give you a glimpse of what we’ve been doing over the past year. In this article, we recap a few of our enhancements and provide a set of resources that you can use to learn more and get the most out of your Amazon Redshift implementation.

In 2017, we made more than 30 announcements about Amazon Redshift. We listened to you, our customers, and delivered Redshift Spectrum, a feature of Amazon Redshift, that gives you the ability to extend analytics to your data lake—without moving data. We launched new DC2 nodes, doubling performance at the same price. We also announced many new features that provide greater scalability, better performance, more automation, and easier ways to manage your analytics workloads.

To see a full list of our launches, visit our what’s new page—and be sure to subscribe to our RSS feed.

Major launches in 2017

Amazon Redshift Spectrumextend analytics to your data lake, without moving data

We launched Amazon Redshift Spectrum to give you the freedom to store data in Amazon S3, in open file formats, and have it available for analytics without the need to load it into your Amazon Redshift cluster. It enables you to easily join datasets across Redshift clusters and S3 to provide unique insights that you would not be able to obtain by querying independent data silos.

With Redshift Spectrum, you can run SQL queries against data in an Amazon S3 data lake as easily as you analyze data stored in Amazon Redshift. And you can do it without loading data or resizing the Amazon Redshift cluster based on growing data volumes. Redshift Spectrum separates compute and storage to meet workload demands for data size, concurrency, and performance. Redshift Spectrum scales processing across thousands of nodes, so results are fast, even with massive datasets and complex queries. You can query open file formats that you already use—such as Apache Avro, CSV, Grok, ORC, Apache Parquet, RCFile, RegexSerDe, SequenceFile, TextFile, and TSV—directly in Amazon S3, without any data movement.

For complex queries, Redshift Spectrum provided a 67 percent performance gain,” said Rafi Ton, CEO, NUVIAD. “Using the Parquet data format, Redshift Spectrum delivered an 80 percent performance improvement. For us, this was substantial.

To learn more about Redshift Spectrum, watch our AWS Summit session Intro to Amazon Redshift Spectrum: Now Query Exabytes of Data in S3, and read our announcement blog post Amazon Redshift Spectrum – Exabyte-Scale In-Place Queries of S3 Data.

DC2 nodes—twice the performance of DC1 at the same price

We launched second-generation Dense Compute (DC2) nodes to provide low latency and high throughput for demanding data warehousing workloads. DC2 nodes feature powerful Intel E5-2686 v4 (Broadwell) CPUs, fast DDR4 memory, and NVMe-based solid state disks (SSDs). We’ve tuned Amazon Redshift to take advantage of the better CPU, network, and disk on DC2 nodes, providing up to twice the performance of DC1 at the same price. Our DC2.8xlarge instances now provide twice the memory per slice of data and an optimized storage layout with 30 percent better storage utilization.

Redshift allows us to quickly spin up clusters and provide our data scientists with a fast and easy method to access data and generate insights,” said Bradley Todd, technology architect at Liberty Mutual. “We saw a 9x reduction in month-end reporting time with Redshift DC2 nodes as compared to DC1.”

Read our customer testimonials to see the performance gains our customers are experiencing with DC2 nodes. To learn more, read our blog post Amazon Redshift Dense Compute (DC2) Nodes Deliver Twice the Performance as DC1 at the Same Price.

Performance enhancements— 3x-5x faster queries

On average, our customers are seeing 3x to 5x performance gains for most of their critical workloads.

We introduced short query acceleration to speed up execution of queries such as reports, dashboards, and interactive analysis. Short query acceleration uses machine learning to predict the execution time of a query, and to move short running queries to an express short query queue for faster processing.

We launched results caching to deliver sub-second response times for queries that are repeated, such as dashboards, visualizations, and those from BI tools. Results caching has an added benefit of freeing up resources to improve the performance of all other queries.

We also introduced late materialization to reduce the amount of data scanned for queries with predicate filters by batching and factoring in the filtering of predicates before fetching data blocks in the next column. For example, if only 10 percent of the table rows satisfy the predicate filters, Amazon Redshift can potentially save 90 percent of the I/O for the remaining columns to improve query performance.

We launched query monitoring rules and pre-defined rule templates. These features make it easier for you to set metrics-based performance boundaries for workload management (WLM) queries, and specify what action to take when a query goes beyond those boundaries. For example, for a queue that’s dedicated to short-running queries, you might create a rule that aborts queries that run for more than 60 seconds. To track poorly designed queries, you might have another rule that logs queries that contain nested loops.

Customer insights

Amazon Redshift and Redshift Spectrum serve customers across a variety of industries and sizes, from startups to large enterprises. Visit our customer page to see the success that customers are having with our recent enhancements. Learn how companies like Liberty Mutual Insurance saw a 9x reduction in month-end reporting time using DC2 nodes. On this page, you can find case studies, videos, and other content that show how our customers are using Amazon Redshift to drive innovation and business results.

In addition, check out these resources to learn about the success our customers are having building out a data warehouse and data lake integration solution with Amazon Redshift:

Partner solutions

You can enhance your Amazon Redshift data warehouse by working with industry-leading experts. Our AWS Partner Network (APN) Partners have certified their solutions to work with Amazon Redshift. They offer software, tools, integration, and consulting services to help you at every step. Visit our Amazon Redshift Partner page and choose an APN Partner. Or, use AWS Marketplace to find and immediately start using third-party software.

To see what our Partners are saying about Amazon Redshift Spectrum and our DC2 nodes mentioned earlier, read these blog posts:

Resources

Blog posts

Visit the AWS Big Data Blog for a list of all Amazon Redshift articles.

YouTube videos

GitHub

Our community of experts contribute on GitHub to provide tips and hints that can help you get the most out of your deployment. Visit GitHub frequently to get the latest technical guidance, code samples, administrative task automation utilities, the analyze & vacuum schema utility, and more.

Customer support

If you are evaluating or considering a proof of concept with Amazon Redshift, or you need assistance migrating your on-premises or other cloud-based data warehouse to Amazon Redshift, our team of product experts and solutions architects can help you with architecting, sizing, and optimizing your data warehouse. Contact us using this support request form, and let us know how we can assist you.

If you are an Amazon Redshift customer, we offer a no-cost health check program. Our team of database engineers and solutions architects give you recommendations for optimizing Amazon Redshift and Amazon Redshift Spectrum for your specific workloads. To learn more, email us at [email protected].

If you have any questions, email us at [email protected].

 


Additional Reading

If you found this post useful, be sure to check out Amazon Redshift Spectrum – Exabyte-Scale In-Place Queries of S3 Data, Using Amazon Redshift for Fast Analytical Reports and How to Migrate Your Oracle Data Warehouse to Amazon Redshift Using AWS SCT and AWS DMS.


About the Author

Larry Heathcote is a Principle Product Marketing Manager at Amazon Web Services for data warehousing and analytics. Larry is passionate about seeing the results of data-driven insights on business outcomes. He enjoys family time, home projects, grilling out and the taste of classic barbeque.

 

 

 

[$] Some advanced BCC topics

Post Syndicated from corbet original https://lwn.net/Articles/747640/rss

The BPF virtual machine is working its way into an increasing number of
kernel subsystems. The previous article in
this series
introduced the BPF Compiler Collection (BCC), which
provides a set of tools for working with BPF. But there is more to BCC
than a set of administrative tools; it also provides a development
environment for those wanting to create their own BPF-based utilities.
Read on for an exploration of that environment and how it can be used to
create programs and attach them to tracepoints.

Adding Visible Electronic Signatures To PDFs

Post Syndicated from Bozho original https://techblog.bozho.net/adding-visible-electronic-signatures-pdf/

I’m aware this is going to be a very niche topic. Electronically signing PDFs is far from a mainstream usecase. However, I’ll write it for two reasons – first, I think it will be very useful for those few who actually need it, and second, I think it will become more and more common as the eIDAS regulation gain popularity – it basically says that electronic signatures are recognized everywhere in Europe (now, it’s not exactly true, because of some boring legal details, but anyway).

So, what is the usecase – first, you have to electronically sign the PDF with an a digital signature (the legal term is “electronic signature”, so I’ll use them interchangeably, although they don’t fully match – e.g. any electronic data applied to other data can be seen as an electronic signature, where a digital signature is the PKI-based signature).

Second, you may want to actually display the signature on the pages, rather than have the PDF reader recognize it and show it in some side-panel. Why is that? Because people are used to seeing signatures on pages and some may insist on having the signature visible (true story – I’ve got a comment that a detached signature “is not a REAL electronic signature, because it’s not visible on the page”).

Now, notice that I wrote “pages”, on “page”. Yes, an electronic document doesn’t have pages – it’s a stream of bytes. So having the signature just on the last page is okay. But, again, people are used to signing all pages, so they’d prefer the electronic signature to be visible on all pages.

And that makes the task tricky – PDF is good with having a digital signature box on the last page, but having multiple such boxes doesn’t work well. Therefore one has to add other types of annotations that look like a signature box and when clicked open the signature panel (just like an actual signature box).

I have to introduce here DSS – a wonderful set of components by the European Commission that can be used to sign and validate all sorts of electronic signatures. It’s open source, you can use at any way you like. Deploy the demo application, use only the libraries, whatever. It includes the signing functionality out of the box – just check the PAdESService or the PDFBoxSignatureService. It even includes the option to visualize the signature once (on a particular page).

However, it doesn’t have the option to show “stamps” (images) on multiple pages. Which is why I forked it and implemented the functionality. Most of my changes are in the PDFBoxSignatureService in the loadAndStampDocument(..) method. If you want to use that functionality you can just build a jar from my fork and use it (by passing the appropriate SignatureImageParameters to PAdESSErvice.sign(..) to define how the signature will look like).

Why is this needed in the first place? Because when a document is signed, you cannot modify it anymore, as you will change the hash. However, PDFs have incremental updates which allow appending to the document and thus having a newer version without modifying anything in the original version. That way the signature is still valid (the originally signed content is not modified), but new stuff is added. In our case, this new stuff is some “annotations”, which represent an image and a clickable area that opens the signature panel (in Adobe Reader at least). And while they are added before the signature box is added, if there are more than one signer, then the 2nd signer’s annotations are added after the first signature.

Sadly, PDFBox doesn’t support that out of the box. Well, it almost does – the piece of code below looks hacky, and it took a while to figure what exactly should be called and when, but it works with just a single reflection call:

    for (PDPage page : pdDocument.getPages()) {
        // reset existing annotations (needed in order to have the stamps added)
        page.setAnnotations(null);
    }
    // reset document outline (needed in order to have the stamps added)
    pdDocument.getDocumentCatalog().setDocumentOutline(null);
    List<PDAnnotation> annotations = addStamps(pdDocument, parameters);
			
    setDocumentId(parameters, pdDocument);
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    try (COSWriter writer = new COSWriter(baos, new RandomAccessBuffer(pdfBytes))) {
        // force-add the annotations (wouldn't be saved in incremental updates otherwise)
        annotations.forEach(ann -> addObjectToWrite(writer, ann.getCOSObject()));
				
        // technically the same as saveIncremental but with more control
        writer.write(pdDocument);
    }
    pdDocument.close();
    pdDocument = PDDocument.load(baos.toByteArray());
    ...
}

private void addObjectToWrite(COSWriter writer, COSDictionary cosObject) {
    // the COSWriter does not expose the addObjectToWrite method, so we need reflection to add the annotations
    try {
        Method method = writer.getClass().getDeclaredMethod("addObjectToWrite", COSBase.class);
        method.setAccessible(true);
        method.invoke(writer, cosObject);
    } catch (Exception ex) {
        throw new RuntimeException(ex);
    }
}

What it does is – loads the original PDF, clears some internal catalogs, adds the annotations (images) to all pages, and then “force-add the annotations” because they “wouldn’t be saved in incremental updates otherwise”. I hope PDFBox make this a little more straightforward, but for the time being this works, and it doesn’t invalidate the existing signatures.

I hope that this posts introduces you to:

  • the existence of legally binding electronic signatures
  • the existence of the DSS utilities
  • the PAdES standard for PDF signing
  • how to place more than just one signature box in a PDF document

And I hope this article becomes more and more popular over time, as more and more businesses realize they could make use of electronic signatures.

The post Adding Visible Electronic Signatures To PDFs appeared first on Bozho's tech blog.

FOSS Project Spotlight: LinuxBoot (Linux Journal)

Post Syndicated from jake original https://lwn.net/Articles/747380/rss

Linux Journal takes a look at the newly announced LinuxBoot project. LWN covered a related talk back in November. “Modern firmware generally consists of two main parts: hardware initialization (early stages) and OS loading (late stages). These parts may be divided further depending on the implementation, but the overall flow is similar across boot firmware. The late stages have gained many capabilities over the years and often have an environment with drivers, utilities, a shell, a graphical menu (sometimes with 3D animations) and much more. Runtime components may remain resident and active after firmware exits. Firmware, which used to fit in an 8 KiB ROM, now contains an OS used to boot another OS and doesn’t always stop running after the OS boots. LinuxBoot replaces the late stages with a Linux kernel and initramfs, which are used to load and execute the next stage, whatever it may be and wherever it may come from. The Linux kernel included in LinuxBoot is called the ‘boot kernel’ to distinguish it from the ‘target kernel’ that is to be booted and may be something other than Linux.

Water Utility Infected by Cryptocurrency Mining Software

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2018/02/water_utility_i.html

A water utility in Europe has been infected by cryptocurrency mining software. This is a relatively new attack: hackers compromise computers and force them to mine cryptocurrency for them. This is the first time I’ve seen it infect SCADA systems, though.

It seems that this mining software is benign, and doesn’t affect the performance of the hacked computer. (A smart virus doesn’t kill its host.) But that’s not going to always be the case.