1=pod 2 3=head1 NAME 4 5BF_set_key, BF_encrypt, BF_decrypt, BF_ecb_encrypt, BF_cbc_encrypt, 6BF_cfb64_encrypt, BF_ofb64_encrypt, BF_options - Blowfish encryption 7 8=head1 SYNOPSIS 9 10 #include <openssl/blowfish.h> 11 12 void BF_set_key(BF_KEY *key, int len, const unsigned char *data); 13 14 void BF_ecb_encrypt(const unsigned char *in, unsigned char *out, 15 BF_KEY *key, int enc); 16 void BF_cbc_encrypt(const unsigned char *in, unsigned char *out, 17 long length, BF_KEY *schedule, 18 unsigned char *ivec, int enc); 19 void BF_cfb64_encrypt(const unsigned char *in, unsigned char *out, 20 long length, BF_KEY *schedule, 21 unsigned char *ivec, int *num, int enc); 22 void BF_ofb64_encrypt(const unsigned char *in, unsigned char *out, 23 long length, BF_KEY *schedule, 24 unsigned char *ivec, int *num); 25 const char *BF_options(void); 26 27 void BF_encrypt(BF_LONG *data, const BF_KEY *key); 28 void BF_decrypt(BF_LONG *data, const BF_KEY *key); 29 30=head1 DESCRIPTION 31 32This library implements the Blowfish cipher, which was invented and described 33by Counterpane (see http://www.counterpane.com/blowfish.html ). 34 35Blowfish is a block cipher that operates on 64 bit (8 byte) blocks of data. 36It uses a variable size key, but typically, 128 bit (16 byte) keys are 37considered good for strong encryption. Blowfish can be used in the same 38modes as DES (see L<des_modes(7)>). Blowfish is currently one 39of the faster block ciphers. It is quite a bit faster than DES, and much 40faster than IDEA or RC2. 41 42Blowfish consists of a key setup phase and the actual encryption or decryption 43phase. 44 45BF_set_key() sets up the B<BF_KEY> B<key> using the B<len> bytes long key 46at B<data>. 47 48BF_ecb_encrypt() is the basic Blowfish encryption and decryption function. 49It encrypts or decrypts the first 64 bits of B<in> using the key B<key>, 50putting the result in B<out>. B<enc> decides if encryption (B<BF_ENCRYPT>) 51or decryption (B<BF_DECRYPT>) shall be performed. The vector pointed at by 52B<in> and B<out> must be 64 bits in length, no less. If they are larger, 53everything after the first 64 bits is ignored. 54 55The mode functions BF_cbc_encrypt(), BF_cfb64_encrypt() and BF_ofb64_encrypt() 56all operate on variable length data. They all take an initialization vector 57B<ivec> which needs to be passed along into the next call of the same function 58for the same message. B<ivec> may be initialized with anything, but the 59recipient needs to know what it was initialized with, or it won't be able 60to decrypt. Some programs and protocols simplify this, like SSH, where 61B<ivec> is simply initialized to zero. 62BF_cbc_encrypt() operates on data that is a multiple of 8 bytes long, while 63BF_cfb64_encrypt() and BF_ofb64_encrypt() are used to encrypt a variable 64number of bytes (the amount does not have to be an exact multiple of 8). The 65purpose of the latter two is to simulate stream ciphers, and therefore, they 66need the parameter B<num>, which is a pointer to an integer where the current 67offset in B<ivec> is stored between calls. This integer must be initialized 68to zero when B<ivec> is initialized. 69 70BF_cbc_encrypt() is the Cipher Block Chaining function for Blowfish. It 71encrypts or decrypts the 64 bits chunks of B<in> using the key B<schedule>, 72putting the result in B<out>. B<enc> decides if encryption (BF_ENCRYPT) or 73decryption (BF_DECRYPT) shall be performed. B<ivec> must point at an 8 byte 74long initialization vector. 75 76BF_cfb64_encrypt() is the CFB mode for Blowfish with 64 bit feedback. 77It encrypts or decrypts the bytes in B<in> using the key B<schedule>, 78putting the result in B<out>. B<enc> decides if encryption (B<BF_ENCRYPT>) 79or decryption (B<BF_DECRYPT>) shall be performed. B<ivec> must point at an 808 byte long initialization vector. B<num> must point at an integer which must 81be initially zero. 82 83BF_ofb64_encrypt() is the OFB mode for Blowfish with 64 bit feedback. 84It uses the same parameters as BF_cfb64_encrypt(), which must be initialized 85the same way. 86 87BF_encrypt() and BF_decrypt() are the lowest level functions for Blowfish 88encryption. They encrypt/decrypt the first 64 bits of the vector pointed by 89B<data>, using the key B<key>. These functions should not be used unless you 90implement 'modes' of Blowfish. The alternative is to use BF_ecb_encrypt(). 91If you still want to use these functions, you should be aware that they take 92each 32-bit chunk in host-byte order, which is little-endian on little-endian 93platforms and big-endian on big-endian ones. 94 95=head1 RETURN VALUES 96 97None of the functions presented here return any value. 98 99=head1 NOTE 100 101Applications should use the higher level functions 102L<EVP_EncryptInit(3)> etc. instead of calling these 103functions directly. 104 105=head1 SEE ALSO 106 107L<EVP_EncryptInit(3)>, 108L<des_modes(7)> 109 110=head1 COPYRIGHT 111 112Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved. 113 114Licensed under the OpenSSL license (the "License"). You may not use 115this file except in compliance with the License. You can obtain a copy 116in the file LICENSE in the source distribution or at 117L<https://www.openssl.org/source/license.html>. 118 119=cut 120