| Encryption |
\(c[i] = E(k, m[i])\) |
\(c[i] = E(k, m[i] \oplus c[i{-}1])\) |
\(c[i] = m[i] \oplus E(k, (n, \langle i \rangle_b))\) |
| Decryption |
\(m[i] = D(k, c[i])\) |
\(m[i] = D(k, c[i]) \oplus c[i{-}1]\) |
\(m[i] = c[i] \oplus E(k, (n, \langle i \rangle_b))\) |
| \(\texttt{Enc}\) parallelisable |
Yes |
No |
Yes |
| \(\texttt{Dec}\) parallelisable |
Yes |
Yes |
Yes |
| Random read |
Yes |
Decryption only |
Yes |
| Partial last block |
Padding required |
Padding required |
Yes |
| IV / Nonce |
None |
Unpredictable IV |
Unique nonce |
| Semantically secure |
No |
Yes |
Yes |
| Notes |
Leaks block equality |
IV sent unencrypted |
\(\texttt{Enc}\) = \(\texttt{Dec}\) (stream cipher) |
