+ * The following ciphers are supported:
+ *
+ * aes-256-ctr AES-256, Counter mode
+ * aes-192-ctr AES-192, Counter mode
+ * aes-128-ctr AES,128, Counter mode
+ * aes-256-cbc AES-256, Cipher block chaining mode
+ * aes-192-cbc AES-192, Cipher block chaining mode
+ * aes-128-cbc AES,128, Cipher block chaining mode
+ * twofish-256-cbc Twofish-256, Cipher block chaining mode
+ * twofish-192-cbc Twofish-192, Cipher block chaining mode
+ * twofish-128-cbc Twofish-128, Cipher block chaining mode
+ *
+ * Notes about modes:
+ *
+ * The CTR is normal counter mode. The CTR mode does not require the
+ * plaintext length to be multiple by the cipher block size. If the last
+ * plaintext block is shorter the remaining bits of the key stream are
+ * used next time silc_cipher_encrypt is called. If silc_cipher_set_iv
+ * is called it will reset the counter for a new block (discarding any
+ * remaining bits from previous key stream).
+ *
+ * The CBC is mode is a standard CBC mode. The plaintext length must be
+ * multiple by the cipher block size. If it isn't the plaintext must be
+ * padded.
+ *