201–210 of 294 posts
It deters automated sandbox analysis by asking the user to use a password in the email body. For zip,pdf,etc... you can easily tell when they're encrypted and block/alert on them but not so with non-standard methods like this.
I'm not a cryptographer, but I'm pretty sure that CBC ( https://github.com/robinmoisson/staticrypt/blob/main/lib/cry... ) should be replaced with GCM ( https://developer.mozilla.org/en-US/docs/Web/API/SubtleCrypt... ) since this is not a stream. https://security.stackexchange.com/questions/184305/why-woul... (also, use the built-in WebCrypto API instead of the crypto-js package)
I think you might be referencing that the incorrect use of CBC leads to chosen-plaintext attacks, chosen-ciphertext attacks, or padding oracle attacks. GCM is AEAD, providing ciphertext authentication. [1]
For those reasons that you mention, use of encryption should always have a design review.
[1] https://en.wikipedia.org/wiki/Authenticated_encryption#Authe...
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You mean, unless they tamper with the Javascript to capture the password (or the derived key).
I designed a similar tool with that threat model in mind: the resulting HTML/JS is as minimal as possible so it’s possible to inspect before entering the password. Of course assumes safe browser and client machine.. https://github.com/dividuum/html-vault
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> CBC is far easier to implement... Never implement your own cryptography. Edit: In fact an incorrect implementation of CBC mode famously caused a vulnerability in Microsoft's ASP.NET in 2010 ( https://learn.microsoft.com/en-us/security-updates/securityb... ). The margin for error is small and even subtle mistakes or incorrect design can cripple security. Even Microsoft got it wrong once (although they handled remedi…
Or... you can have a more nuanced viewpoint and note that CBC is really, really, really easy to implement, and _really_ doesn't fall into that category of discussion. The reason you don't implement your own block ciphers is because side-channel attacks are damn near impossible for normal programmers to understand. Especially timing attacks. But block-modes of operation? Some of them are really easy. I've ever heard o…
For anyone else wondering what the KDF is, it appears to be PBKDF2 with 1000 iterations: https://github.com/robinmoisson/staticrypt/blob/5dac008ba644...
I'm not a cryptographer, but I'm pretty sure that CBC ( https://github.com/robinmoisson/staticrypt/blob/main/lib/cry... ) should be replaced with GCM ( https://developer.mozilla.org/en-US/docs/Web/API/SubtleCrypt... ) since this is not a stream. https://security.stackexchange.com/questions/184305/why-woul... (also, use the built-in WebCrypto API instead of the crypto-js package)
CBC is far easier to implement than GCM mode. I bet that most programmers cannot implement a Galois Field in Javascript. Meanwhile, CBC is just "encrypt then xor".
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A more lightweight solution would be to let the Webserver (nginx, https, whatever) password-protect the site. No JavaScript required a d highly efficient
Requiring some sort of VM or container to run this webserver on? Is it possible that's way more onerous than a static html file which can be emailed around? Are you sure nginx is even going to be around in, say, 15 years? (think password protected PDF but in html and allowing for JavaScript.)
Considering it's been around longer than that, yes I think it will be around in 15 years
My recent solution to this problem -- for an entire static site -- was to use HTTP Basic authentication with CloudFlare Pages: https://github.com/garrison/cloudflare-pages-shared-password
And it’s superior in many ways, since the file is never delivered until authentication has been completed.
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Padding is an important part of CBC.
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That's not true and extremely dangerous to say. In an offline, black-box scenario no server is needed for a padding-oracle. You are thinking of a side-channel oracle. A padding-oracle attack can absolutely be feasible in many cases.