Block.aes_encrypt
The AES block cipher, in encryption mode. The string argument is the key; its length must be 16, 24 or 32 bytes.
transform src spos dst dpos
encrypts or decrypts one block of data. The input data is read from byte array src
at positions spos, ..., spos + blocksize - 1
, and the output data is stored in byte array dst
at positions dpos, ..., dpos + blocksize - 1
.