blowfish(3) OpenSSL blowfish(3)

NAME
       blowfish, BFsetkey, BFencrypt, BFdecrypt, BFecbencrypt,
       BFcbcencrypt, BFcfb64encrypt, BFofb64encrypt, BFoptions -
       Blowfish encryption

SYNOPSIS
        #include 

        void BFsetkey(BFKEY *key, int len, const unsigned char *data);

        void BFecbencrypt(const unsigned char *in, unsigned char *out,
                BFKEY *key, int enc);
        void BFcbcencrypt(const unsigned char *in, unsigned char *out,
                long length, BFKEY *schedule, unsigned char *ivec, int enc);
        void BFcfb64encrypt(const unsigned char *in, unsigned char *out,
                long length, BFKEY *schedule, unsigned char *ivec, int *num,
                int enc);
        void BFofb64encrypt(const unsigned char *in, unsigned char *out,
                long length, BFKEY *schedule, unsigned char *ivec, int *num);
        const char *BFoptions(void);

        void BFencrypt(BFLONG *data,const BFKEY *key);
        void BFdecrypt(BFLONG *data,const BFKEY *key);

DESCRIPTION
       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 desmodes(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.

       BFsetkey() sets up the BBFFKKEEYY kkeeyy using the lleenn bytes long key at
       ddaattaa.

       BFecbencrypt() is the basic Blowfish encryption and decryption
       function.  It encrypts or decrypts the first 64 bits of iinn using the
       key kkeeyy, putting the result in oouutt.  eenncc decides if encryption
       (BBFFEENNCCRRYYPPTT) or decryption (BBFFDDEECCRRYYPPTT) shall be performed.  The vector
       pointed at by iinn and oouutt must be 64 bits in length, no less.  If they
       are larger, everything after the first 64 bits is ignored.

       The mode functions BFcbcencrypt(), BFcfb64encrypt() and
       BFofb64encrypt() all operate on variable length data.  They all take
       an initialization vector iivveecc which needs to be passed along into the
       next call of the same function for the same message.  iivveecc 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 iivveecc is simply initialized to
       zero.  BFcbcencrypt() operates on data that is a multiple of 8 bytes
       long, while BFcfb64encrypt() and BFofb64encrypt() 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 nnuumm, which is a
       pointer to an integer where the current offset in iivveecc is stored
       between calls.  This integer must be initialized to zero when iivveecc is
       initialized.

       BFcbcencrypt() is the Cipher Block Chaining function for Blowfish.
       It encrypts or decrypts the 64 bits chunks of iinn using the key
       sscchheedduullee, putting the result in oouutt.  eenncc decides if encryption
       (BFENCRYPT) or decryption (BFDECRYPT) shall be performed.  iivveecc must
       point at an 8 byte long initialization vector.

       BFcfb64encrypt() is the CFB mode for Blowfish with 64 bit feedback.
       It encrypts or decrypts the bytes in iinn using the key sscchheedduullee, putting
       the result in oouutt.  eenncc decides if encryption (BBFFEENNCCRRYYPPTT) or
       decryption (BBFFDDEECCRRYYPPTT) shall be performed.  iivveecc must point at an 8
       byte long initialization vector. nnuumm must point at an integer which
       must be initially zero.

       BFofb64encrypt() is the OFB mode for Blowfish with 64 bit feedback.
       It uses the same parameters as BFcfb64encrypt(), which must be
       initialized the same way.

       BFencrypt() and BFdecrypt() are the lowest level functions for
       Blowfish encryption.  They encrypt/decrypt the first 64 bits of the
       vector pointed by ddaattaa, using the key kkeeyy.  These functions should not
       be used unless you implement 'modes' of Blowfish.  The alternative is
       to use BFecbencrypt().  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.

RETURN VALUES
       None of the functions presented here return any value.

NNOOTTEE
       Applications should use the higher level functions EVPEncryptInit(3)
       etc. instead of calling the blowfish functions directly.

SEE ALSO
       desmodes(7)

HISTORY       The Blowfish functions are available in all versions of SSLeay and
       OpenSSL.



0.9.7l                            2005-02-19                       blowfish(3)