1*2175Sjp161948=pod 2*2175Sjp161948 3*2175Sjp161948=head1 NAME 4*2175Sjp161948 5*2175Sjp161948blowfish, BF_set_key, BF_encrypt, BF_decrypt, BF_ecb_encrypt, BF_cbc_encrypt, 6*2175Sjp161948BF_cfb64_encrypt, BF_ofb64_encrypt, BF_options - Blowfish encryption 7*2175Sjp161948 8*2175Sjp161948=head1 SYNOPSIS 9*2175Sjp161948 10*2175Sjp161948 #include <openssl/blowfish.h> 11*2175Sjp161948 12*2175Sjp161948 void BF_set_key(BF_KEY *key, int len, const unsigned char *data); 13*2175Sjp161948 14*2175Sjp161948 void BF_ecb_encrypt(const unsigned char *in, unsigned char *out, 15*2175Sjp161948 BF_KEY *key, int enc); 16*2175Sjp161948 void BF_cbc_encrypt(const unsigned char *in, unsigned char *out, 17*2175Sjp161948 long length, BF_KEY *schedule, unsigned char *ivec, int enc); 18*2175Sjp161948 void BF_cfb64_encrypt(const unsigned char *in, unsigned char *out, 19*2175Sjp161948 long length, BF_KEY *schedule, unsigned char *ivec, int *num, 20*2175Sjp161948 int enc); 21*2175Sjp161948 void BF_ofb64_encrypt(const unsigned char *in, unsigned char *out, 22*2175Sjp161948 long length, BF_KEY *schedule, unsigned char *ivec, int *num); 23*2175Sjp161948 const char *BF_options(void); 24*2175Sjp161948 25*2175Sjp161948 void BF_encrypt(BF_LONG *data,const BF_KEY *key); 26*2175Sjp161948 void BF_decrypt(BF_LONG *data,const BF_KEY *key); 27*2175Sjp161948 28*2175Sjp161948=head1 DESCRIPTION 29*2175Sjp161948 30*2175Sjp161948This library implements the Blowfish cipher, which was invented and described 31*2175Sjp161948by Counterpane (see http://www.counterpane.com/blowfish.html ). 32*2175Sjp161948 33*2175Sjp161948Blowfish is a block cipher that operates on 64 bit (8 byte) blocks of data. 34*2175Sjp161948It uses a variable size key, but typically, 128 bit (16 byte) keys are 35*2175Sjp161948considered good for strong encryption. Blowfish can be used in the same 36*2175Sjp161948modes as DES (see L<des_modes(7)|des_modes(7)>). Blowfish is currently one 37*2175Sjp161948of the faster block ciphers. It is quite a bit faster than DES, and much 38*2175Sjp161948faster than IDEA or RC2. 39*2175Sjp161948 40*2175Sjp161948Blowfish consists of a key setup phase and the actual encryption or decryption 41*2175Sjp161948phase. 42*2175Sjp161948 43*2175Sjp161948BF_set_key() sets up the B<BF_KEY> B<key> using the B<len> bytes long key 44*2175Sjp161948at B<data>. 45*2175Sjp161948 46*2175Sjp161948BF_ecb_encrypt() is the basic Blowfish encryption and decryption function. 47*2175Sjp161948It encrypts or decrypts the first 64 bits of B<in> using the key B<key>, 48*2175Sjp161948putting the result in B<out>. B<enc> decides if encryption (B<BF_ENCRYPT>) 49*2175Sjp161948or decryption (B<BF_DECRYPT>) shall be performed. The vector pointed at by 50*2175Sjp161948B<in> and B<out> must be 64 bits in length, no less. If they are larger, 51*2175Sjp161948everything after the first 64 bits is ignored. 52*2175Sjp161948 53*2175Sjp161948The mode functions BF_cbc_encrypt(), BF_cfb64_encrypt() and BF_ofb64_encrypt() 54*2175Sjp161948all operate on variable length data. They all take an initialization vector 55*2175Sjp161948B<ivec> which needs to be passed along into the next call of the same function 56*2175Sjp161948for the same message. B<ivec> may be initialized with anything, but the 57*2175Sjp161948recipient needs to know what it was initialized with, or it won't be able 58*2175Sjp161948to decrypt. Some programs and protocols simplify this, like SSH, where 59*2175Sjp161948B<ivec> is simply initialized to zero. 60*2175Sjp161948BF_cbc_encrypt() operates on data that is a multiple of 8 bytes long, while 61*2175Sjp161948BF_cfb64_encrypt() and BF_ofb64_encrypt() are used to encrypt an variable 62*2175Sjp161948number of bytes (the amount does not have to be an exact multiple of 8). The 63*2175Sjp161948purpose of the latter two is to simulate stream ciphers, and therefore, they 64*2175Sjp161948need the parameter B<num>, which is a pointer to an integer where the current 65*2175Sjp161948offset in B<ivec> is stored between calls. This integer must be initialized 66*2175Sjp161948to zero when B<ivec> is initialized. 67*2175Sjp161948 68*2175Sjp161948BF_cbc_encrypt() is the Cipher Block Chaining function for Blowfish. It 69*2175Sjp161948encrypts or decrypts the 64 bits chunks of B<in> using the key B<schedule>, 70*2175Sjp161948putting the result in B<out>. B<enc> decides if encryption (BF_ENCRYPT) or 71*2175Sjp161948decryption (BF_DECRYPT) shall be performed. B<ivec> must point at an 8 byte 72*2175Sjp161948long initialization vector. 73*2175Sjp161948 74*2175Sjp161948BF_cfb64_encrypt() is the CFB mode for Blowfish with 64 bit feedback. 75*2175Sjp161948It encrypts or decrypts the bytes in B<in> using the key B<schedule>, 76*2175Sjp161948putting the result in B<out>. B<enc> decides if encryption (B<BF_ENCRYPT>) 77*2175Sjp161948or decryption (B<BF_DECRYPT>) shall be performed. B<ivec> must point at an 78*2175Sjp1619488 byte long initialization vector. B<num> must point at an integer which must 79*2175Sjp161948be initially zero. 80*2175Sjp161948 81*2175Sjp161948BF_ofb64_encrypt() is the OFB mode for Blowfish with 64 bit feedback. 82*2175Sjp161948It uses the same parameters as BF_cfb64_encrypt(), which must be initialized 83*2175Sjp161948the same way. 84*2175Sjp161948 85*2175Sjp161948BF_encrypt() and BF_decrypt() are the lowest level functions for Blowfish 86*2175Sjp161948encryption. They encrypt/decrypt the first 64 bits of the vector pointed by 87*2175Sjp161948B<data>, using the key B<key>. These functions should not be used unless you 88*2175Sjp161948implement 'modes' of Blowfish. The alternative is to use BF_ecb_encrypt(). 89*2175Sjp161948If you still want to use these functions, you should be aware that they take 90*2175Sjp161948each 32-bit chunk in host-byte order, which is little-endian on little-endian 91*2175Sjp161948platforms and big-endian on big-endian ones. 92*2175Sjp161948 93*2175Sjp161948=head1 RETURN VALUES 94*2175Sjp161948 95*2175Sjp161948None of the functions presented here return any value. 96*2175Sjp161948 97*2175Sjp161948=head1 NOTE 98*2175Sjp161948 99*2175Sjp161948Applications should use the higher level functions 100*2175Sjp161948L<EVP_EncryptInit(3)|EVP_EncryptInit(3)> etc. instead of calling the 101*2175Sjp161948blowfish functions directly. 102*2175Sjp161948 103*2175Sjp161948=head1 SEE ALSO 104*2175Sjp161948 105*2175Sjp161948L<des_modes(7)|des_modes(7)> 106*2175Sjp161948 107*2175Sjp161948=head1 HISTORY 108*2175Sjp161948 109*2175Sjp161948The Blowfish functions are available in all versions of SSLeay and OpenSSL. 110*2175Sjp161948 111*2175Sjp161948=cut 112*2175Sjp161948 113