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Show HN: InstantCryptor – AES256 Encryption for Dropbox and Google Drive

instantcryptor.com

21–30 of 52 posts

Re: Show HN: InstantCryptor – AES256 Encryption for Dropbox and Google Drive

#21
post #18

We are using CBC as block cipher mode. I totally understand that open sourcing the complete code is the only way for you to review it and trust it completely. We decided to write a detailed report about the encryption and how we use it and will publish the report soon via Twitter.

CBC mode by itself is insecure.

Re: Show HN: InstantCryptor – AES256 Encryption for Dropbox and Google Drive

#22
post #4

>> The password will be hashed with the SHA256 algorithm, the mode for encryption is 256 Bit Rijndael/AES SHA256 is not a KDF, AES-256 is not a block cipher mode. Where is the source code?

PBKDF2 is still the gold standard for converting a password to an encryption key, right? bcrypt has some desirable properties, but it has a fixed output length of 192 bits.

Re: Show HN: InstantCryptor – AES256 Encryption for Dropbox and Google Drive

#23
post #21
post #18

We are using CBC as block cipher mode. I totally understand that open sourcing the complete code is the only way for you to review it and trust it completely. We decided to write a detailed report about the encryption and how we use it and will publish the report soon via Twitter.

CBC mode by itself is insecure.

OP: You should listen to tptacek. He's forgotten more about crypto than some people have ever learned. :)

Re: Show HN: InstantCryptor – AES256 Encryption for Dropbox and Google Drive

#24
ooh. I made an app that encrypts files on Android written in Java and has a C# written client for Windows. I have released the java source code. I should post it here on HN to look at it and rip me a new one. What I am sketchy about is how does embedding an unencrypted salt used for the PBKDF2 in the file not potentially make guessing of the passphrase easier

Re: Show HN: InstantCryptor – AES256 Encryption for Dropbox and Google Drive

#25

ooh. I made an app that encrypts files on Android written in Java and has a C# written client for Windows. I have released the java source code. I should post it here on HN to look at it and rip me a new one. What I am sketchy about is how does embedding an unencrypted salt used for the PBKDF2 in the file not potentially make guessing of the passphrase easier

Nice points.

Re: Show HN: InstantCryptor – AES256 Encryption for Dropbox and Google Drive

#28
post #9

Earlier quoted context omitted.

Wolf is 100% correct. These details make it sound like this product is insecure. We definitely don't want ecb mode or a weak kdf like 1 round of sha256 with no salt. BUT before anyone lambasts this guy, it's good the author posted so mistakes can be learned from the feedback, that way others get exposed to the issues, and less mistakes are made in the future. In my opinion, there is too much hate for people who make…

This is true for every kind of software except security things. It's really hard for a novice to find something that will actually protect them in between all the "convenient cloud solutions" that an intern cobbled together in their lunch break using some javascript they found on github.

Why not just use NaCl or libsodium... no need to muck about implementing things you don't fully understand.

Re: Show HN: InstantCryptor – AES256 Encryption for Dropbox and Google Drive

#29
I've built a similar piece of javascript crypto: PasswordProtectMyFile.com. It's a single HTML page that can work with internet turned off. The ciphertext is another HTML page with all the javascript needed to decrypt itself.

It's open source: https://github.com/louissobel/ppmf

Re: Show HN: InstantCryptor – AES256 Encryption for Dropbox and Google Drive

#30
post #5
post #4

>> The password will be hashed with the SHA256 algorithm, the mode for encryption is 256 Bit Rijndael/AES SHA256 is not a KDF, AES-256 is not a block cipher mode. Where is the source code?

I really dislike when companies say it their product encrypts with "256-bit encryption" or "AES-256". Like you said, that is an incomplete description of an encryption scheme. The choice of block cipher mode can immediately make or break my opinion of a product, and when developers omit what mode they've chosen, I lean toward break.

Heh, that reminds me of when the "Trillian" IM client advertised "128-bit blowfish" encryption, but used 128-bit DH to negotiate the key (this many years ago).
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