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Channel: Uncategorized – Charles Engelke's Blog
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AWS Linux AMI Administrative Accounts

It’s been nearly a year since I posted here. I should get back in the habit. Here’s a useful bit of information. I want to create new EC2 Linux instances with separate administrative accounts for one...

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Amazon Workspaces Thoughts

I’ve been using Amazon Workspaces since January 2014 and I’m both impressed and disappointed in it. Impressed, because it provides a Windows desktop as a service that is almost indistinguishable to the...

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Exploring the new Web Cryptography API

I’m very interested in doing cryptography in the browser for things like end-to-end sealing of data and digital signatures. It’s been possible to do some of these things, but not practical. The W3C’s...

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Symmetric Cryptography in the Browser – Part 1

I’m going to start exploring the Web Cryptography API with just about the simplest use case I can think of: symmetric encryption with AES. The user will select a file, have the browser encrypt it, and...

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Symmetric Cryptography in the Browser – Part 2

This post is part of a series on cryptography in the browser. My last post covered the basics of encrypting and decrypting with the Web Cryptography API, but had no practical use. That’s because you...

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Symmetric Cryptography in the Browser – Part 3

This post is part of a series on cryptography in the browser. Previous posts have used the new Web Cryptography API to create and manage AES keys, and encrypt and decrypt strings. Now we will read a...

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Symmetric Cryptography in the Browser – Conclusion

This series of posts is almost complete. We’ve created, imported, and exported AES keys and used them to encrypt and decrypt files, all inside a standard web browser using the new Web Cryptography API....

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Public Key Cryptography in the Browser

Update August 30, 2014: The Web Cryptography API has dropped support of the RSAES-PKCS1-v1_5 algorithm that was used here originally, so this post has been changed to use RSA-OAEP instead. There’s a...

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Digital Signatures in the Browser

Digital signatures are kind of a mirror image of public-key encryption. They use essentially the same algorithms and kinds of key pairs, but for authentication instead of secrecy. Alice can send Bob a...

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Changes to the Web Cryptography API

Chrome 37 made it to Stable a few days ago, and now supports the Web Cryptography API without needing to set a special flag. YAY! But it dropped support for the RSAES-PKCS1-v1_5 algorithm so now the...

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Saving Cryptographic Keys in the Browser

Prior posts here have used the Web Cryptography API to encrypt and decrypt files, and to sign and verify them. But those examples have no practical use because the keys being used are stored in...

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Parsing BER and DER encoded ASN.1 Objects

[Updated October 21, 2014: Fixed error about how an indefinite length is encoded. It is not encoded as 0x00. It is encoded as 0x80. Text and code have been corrected.] The question that likely comes to...

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Web Crypto and X.509 Certificates

If you are going to use cryptography in the browser, there’s a good chance you will want to deal with X.509 certificates. This post is going to get started by using the Web Cryptography API to do two...

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Deriving Keys from Passwords with WebCrypto

It has been quite a while since my last post. I got painted into a corner trying to import key pairs that were from the Windows 7 certificate store using the Web Cryptography API. The problem is that...

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Web Crypto on my AndroidWear Watch

I just tried out some of the live web crypto demos that I’ve blogged about on my Moto 360 AndroidWear watch. Most of them read files which doesn’t seem to work on a watch (go figure). But the one that...

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Apple’s Safari Browser and Web Cryptography

As of this writing Apple’s Safari browser still provides the Web Cryptography API via a prefixed name. Instead of using window.crypto.subtle you would use window.crypto.webkitSubtle. Even though it’s...

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Creating X.509 Certificates with Web Crypto and PKIjs

I wrote a couple of posts last fall looking into working with X.509 certificates. Doing so requires a lot of very detailed, complicated bit and byte twiddling, and as a result I got so discouraged I...

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Where Can You use the Web Cryptography API Today?

[Update March 6: it turns out that Firefox does support PBKDF2 on all platforms, but only with SHA-1. I had only tested with SHA-2 hashes so I missed it. I’ve updated the table.] I tested out all the...

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#FluentConf talk on Cryptography in the Browser

I just posted the video of my talk at the 2015 O’Reilly Fluent Conference. The slides themselves are available, too. I also have a web page with a lot of resources on the Web Cryptography API.Filed...

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AlgorithmIdentifier in WebCrypto

I just replied to a comment by middleendian’s blog on a post from last August asking about the AlgorithmIdentifier argument used for the various SubtleCrypto methods. That argument is different for...

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