Package cbc

Package cbc implements the cipher block chaining (CBC) mode of operation for block ciphers.

EncryptAES128 encrypts the data in AES-CBC mode. The key specifies the AES encryption key and iv is a random initialization vector. The data must be padded to AES block size.

// Case #1: Encrypting 16 bytes (1 block) using AES-CBC with 128-bit key
// Key       : 0x06a9214036b8a15b512e03d534120006
// IV        : 0x3dafba429d9eb430b422da802c9fac41
// Plaintext : "Single block msg"
// Ciphertext: 0xe353779c1079aeb82708942dbe77181a

key := []byte{
   0x06, 0xa9, 0x21, 0x40, 0x36, 0xb8, 0xa1, 0x5b,
   0x51, 0x2e, 0x03, 0xd5, 0x34, 0x12, 0x00, 0x06,
}
iv := []byte{
   0x3d, 0xaf, 0xba, 0x42, 0x9d, 0x9e, 0xb4, 0x30,
   0xb4, 0x22, 0xda, 0x80, 0x2c, 0x9f, 0xac, 0x41,
}
plain := []byte("Single block msg")

cipher := cbc.EncryptAES128(key, iv, plain)
=> e353779c1079aeb82708942dbe77181a

PadAES pads the data to AES cipher block boundary. The padding is filled with byte value describing the padding length. Note that data will be always padded. If the original data is already padded, the padding will be one full AES block.