added aes-gcm

[bmatusiak]

this need testing,

but here in a test scripts for espruino and browser
https://gist.github.com/bmatusiak/c4517056a93f96ea904e85b7f5c0ddb5

[bmatusiak]

yea there still need work to be done

[gfwilliams]

yea there still need work to be done

Thanks! So where are we at with this? Does it build and work ok for those test scripts?

[bmatusiak]

the problem im running into is,

the encrypted data being generated from mbedtls is not verifyable (it can decrypt it, but the gcm tag is invalid causing a failed decryption )..

but encrypted data from webcrypt/browser is verifyable in mbed tls

[bmatusiak]

SIDE note, so instead of hunting down the issue on that yesterday.. i coded up ECDH

https://gist.github.com/bmatusiak/a1ac4b31cf5fd4c2c4ac2a9b0fd377ff

[bmatusiak]

ok i fixed gcm encrypt auth tag
all thats left is importing "additional data"

[bmatusiak]

I changed IV to be a variable length, 16 = {0} is default(for all modes)

added additionalData and tagLength options

var opts = {
        iv: new Uint8Array(16),
        mode: 'GCM',
        additionalData: new Uint8Array( ), //GCM max length AddData is 18446744073709551615 
        tagLength:128, // in bit size (128=16bytes)
    };

[gfwilliams]

Sorry it's taken so long to look into this - but this one in particular looks broken.

iv_bytes is never set, so at this point jsvIterateCallbackToBytes will write into a random area of memory! It's possible that by using &iv_bytes you're just writing onto the stack, but there's definitely an issue here...