Question

I’m aware that in Objective C I can encrypt using AES128 through their native libraries (CommonCrypter.h). In Java, I’m encrypting using AES128 ISO-8859-1 in CFB Mode. In Objective C encoding is done through NSISOLATIN1STRINGENCODING but the problem is there’s no equivalent in CFB Mode. The only modes available are: EBC padding, KCCOPTIONECBMODE and KCCOPTIONPKCS7PADDING.

I need to encrypt using AES128 with CFB Mode. Does anyone have an idea about it?
Thanks a ton in advance.

Answer 1

CBC can be built using ECB, conceptually it’s:

Key K;
InitializationVector IV;
OutputDataStream OS;
Block X;

set X = IV;
for each Block B of data D:
    Block E = ECB(K, B ^ X);
    set X = E
    write E to OS