Android JNI string encryption/decryption

Question

I am trying to do aes encryption/decryption in native code C. Encryption does work but when I try to decrypt the string. It doesn\'t end up as original string. Here is the JNI m

Answer 1

You are using the low level encryption modes of OpenSSL. Your troubles are likely to vanish if you use the higher level EVP_* methods, e.g. for AES/CBC mode encryption. See also this related question.

Answer 2

You provide a key that is 72 bits long (9 characters x 8 bits). But it needs to be 128 bit longs (as you specify in the call to AES_set_encrypt_key). Thus the missing 56 bits will be more or less random (depending on what's next to the ukey array).

To fix it, specified a longer key or fill the remaining bytes with 0s.