NAME
blf_key, blf_enc,
blf_dec, blf_ecb_encrypt,
blf_ecb_decrypt,
blf_cbc_encrypt,
blf_cbc_decrypt —
Blowfish encryption
SYNOPSIS
#include
<blf.h>
void
blf_key(blf_ctx
*state, const u_int8_t
*key, u_int16_t
keylen);
void
blf_enc(blf_ctx
*state, u_int32_t
*data, u_int16_t
blocks);
void
blf_dec(blf_ctx
*state, u_int32_t
*data, u_int16_t
blocks);
void
blf_ecb_encrypt(blf_ctx
*state, u_int8_t
*data, u_int32_t
datalen);
void
blf_ecb_decrypt(blf_ctx
*state, u_int8_t
*data, u_int32_t
datalen);
void
blf_cbc_encrypt(blf_ctx
*state, u_int8_t
*iv, u_int8_t
*data, u_int32_t
datalen);
void
blf_cbc_decrypt(blf_ctx
*state, u_int8_t
*iv, u_int8_t
*data, u_int32_t
datalen);
DESCRIPTION
Blowfish is a fast unpatented block cipher designed by Bruce Schneier. It basically consists of a 16-round Feistel network. The block size is 64 bits and the maximum key size is 448 bits.
The
blf_key()
function initializes the 4 8-bit S-boxes and the 18 Subkeys with the
hexadecimal digits of Pi. The key is used for further randomization. The
first argument to
blf_enc()
is the initialized state derived from blf_key(). The
stream of 32-bit words is encrypted in Electronic Codebook Mode (ECB) and
blocks is the number of 64-bit blocks in the stream.
blf_dec()
is used for decrypting Blowfish encrypted blocks.
The functions
blf_ecb_encrypt()
and
blf_ecb_decrypt()
are used for encrypting and decrypting octet streams in ECB mode. The
functions
blf_cbc_encrypt()
and
blf_cbc_decrypt()
are used for encrypting and decrypting octet streams in Cipherblock Chaining
Mode (CBC). For these functions datalen specifies the
number of octets of data to encrypt or decrypt. It must be a multiple of 8
(64-bit block). The initialisation vector iv points to
an 8-byte buffer.
SEE ALSO
AUTHORS
Niels Provos <provos@physnet.uni-hamburg.de>