OpenSSL blowfish(3openssl) NNNNAAAAMMMMEEEE
blowfish, BF_set_key, BF_encrypt, BF_decrypt,
BF_ecb_encrypt, BF_cbc_encrypt, BF_cfb64_encrypt,
BF_ofb64_encrypt, BF_options - Blowfish encryption
SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS#include
void BF_set_key(BF_KEY *key, int len, const unsigned char *data);
void BF_ecb_encrypt(const unsigned char *in, unsigned char *out,
BF_KEY *key, int enc);
void BF_cbc_encrypt(const unsigned char *in, unsigned char *out,
long length, BF_KEY *schedule, unsigned char *ivec, int enc);
void BF_cfb64_encrypt(const unsigned char *in, unsigned char *out,
long length, BF_KEY *schedule, unsigned char *ivec, int *num,
int enc);void BF_ofb64_encrypt(const unsigned char *in, unsigned char *out,
long length, BF_KEY *schedule, unsigned char *ivec, int *num);
const char *BF_options(void);
void BF_encrypt(BF_LONG *data,const BF_KEY *key);
void BF_decrypt(BF_LONG *data,const BF_KEY *key);
DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN This library implements the Blowfish cipher, which was invented and described by Counterpane (see http://www.counterpane.com/blowfish.html ). Blowfish is a block cipher that operates on 64 bit (8 byte) blocks of data. It uses a variable size key, but typically, 128 bit (16 byte) keys are considered good for strong encryption. Blowfish can be used in the same modes as DES(see des_modes(7)). Blowfish is currently one of the faster
block ciphers. It is quite a bit faster than DES, and much faster than IDEA or RC2. Blowfish consists of a key setup phase and the actual encryption or decryption phase.BF_set_key() sets up the BBBBFFFF_KKKKEEEEYYYY kkkkeeeeyyyy using the lllleeeennnn bytes long
key at ddddaaaattttaaaa.BF_ecb_encrypt() is the basic Blowfish encryption and
decryption function. It encrypts or decrypts the first 64 bits of iiiinnnn using the key kkkkeeeeyyyy, putting the result in oooouuuutttt.eeeennnncccc decides if encryption (BBBBFFFF_EEEENNNNCCCCRRRRYYYYPPPPTTTT) or decryption
(BBBBFFFF_DDDDEEEECCCCRRRRYYYYPPPPTTTT) shall be performed. The vector pointed at by
iiiinnnn and oooouuuutttt must be 64 bits in length, no less. If they are larger, everything after the first 64 bits is ignored.19/Feb/2005 Last change: 0.9.8o 1 OpenSSL blowfish(3openssl)
The mode functions BF_cbc_encrypt(), BF_cfb64_encrypt() and
BF_ofb64_encrypt() all operate on variable length data.
They all take an initialization vector iiiivvvveeeecccc which needs to be passed along into the next call of the same function for the same message. iiiivvvveeeecccc may be initialized with anything, but the recipient needs to know what it was initialized with, or it won't be able to decrypt. Some programs and protocols simplify this, like SSH, where iiiivvvveeeecccc is simplyinitialized to zero. BF_cbc_encrypt() operates on data that
is a multiple of 8 bytes long, while BF_cfb64_encrypt() and
BF_ofb64_encrypt() are used to encrypt an variable number of
bytes (the amount does not have to be an exact multiple of 8). The purpose of the latter two is to simulate stream ciphers, and therefore, they need the parameter nnnnuuuummmm, which is a pointer to an integer where the current offset in iiiivvvveeeecccc is stored between calls. This integer must be initialized to zero when iiiivvvveeeecccc is initialized.BF_cbc_encrypt() is the Cipher Block Chaining function for
Blowfish. It encrypts or decrypts the 64 bits chunks of iiiinnnn using the key sssscccchhhheeeedddduuuulllleeee, putting the result in oooouuuutttt. eeeennnnccccdecides if encryption (BF_ENCRYPT) or decryption
(BF_DECRYPT) shall be performed. iiiivvvveeeecccc must point at an 8
byte long initialization vector.BF_cfb64_encrypt() is the CFB mode for Blowfish with 64 bit
feedback. It encrypts or decrypts the bytes in iiiinnnn using the key sssscccchhhheeeedddduuuulllleeee, putting the result in oooouuuutttt. eeeennnncccc decides ifencryption (BBBBFFFF_EEEENNNNCCCCRRRRYYYYPPPPTTTT) or decryption (BBBBFFFF_DDDDEEEECCCCRRRRYYYYPPPPTTTT) shall be
performed. iiiivvvveeeecccc must point at an 8 byte long initialization vector. nnnnuuuummmm must point at an integer which must be initially zero.BF_ofb64_encrypt() is the OFB mode for Blowfish with 64 bit
feedback. It uses the same parameters asBF_cfb64_encrypt(), which must be initialized the same way.
BF_encrypt() and BF_decrypt() are the lowest level functions
for Blowfish encryption. They encrypt/decrypt the first 64 bits of the vector pointed by ddddaaaattttaaaa, using the key kkkkeeeeyyyy. These functions should not be used unless you implement 'modes' of Blowfish. The alternative is to useBF_ecb_encrypt(). If you still want to use these functions,
you should be aware that they take each 32-bit chunk in
host-byte order, which is little-endian on little-endian
platforms and big-endian on big-endian ones.
RRRREEEETTTTUUUURRRRNNNN VVVVAAAALLLLUUUUEEEESSSS None of the functions presented here return any value. NNNNOOOOTTTTEEEE Applications should use the higher level functions19/Feb/2005 Last change: 0.9.8o 2 OpenSSL blowfish(3openssl)
EVP_EncryptInit(3) etc. instead of calling the blowfish
functions directly. SSSSEEEEEEEE AAAALLLLSSSSOOOOdes_modes(7)
HHHHIIIISSSSTTTTOOOORRRRYYYY The Blowfish functions are available in all versions of SSLeay and OpenSSL.19/Feb/2005 Last change: 0.9.8o 3