64 bits. 56 bit key, plus 8 parity bits. 7 bits of key are followed by one bit of odd parity. For example, the 56-bit key FF FF FF FF FF FF FF would be encoded as FE FE FE FE FE FE FE FE. encrdes supports weak-key checking and parity-fixing to aid pf_key(7P).
See attributes(5) for descriptions of the following attributes:
|ATTRIBUTE TYPE||ATTRIBUTE VALUE|
Madson, C., and Doraswamy, N, RFC 2405, The ESP DES-CBC Cipher Algorithm with Explicit IV, The Internet Society, 1998.
NIST, FIPS PUB 46-2: Data Encryption Standard, December, 1993.