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1 | =pod |
2 | ||
3 | =head1 NAME | |
4 | ||
5 | blowfish, BF_set_key, BF_encrypt, BF_decrypt, BF_ecb_encrypt, BF_cbc_encrypt, | |
6 | BF_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 | ||
4d524e10 UM |
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, | |
1bc74519 | 17 | long length, BF_KEY *schedule, unsigned char *ivec, int enc); |
4d524e10 | 18 | void BF_cfb64_encrypt(const unsigned char *in, unsigned char *out, |
1bc74519 | 19 | long length, BF_KEY *schedule, unsigned char *ivec, int *num, |
4d524e10 UM |
20 | int enc); |
21 | void BF_ofb64_encrypt(const unsigned char *in, unsigned char *out, | |
1bc74519 | 22 | long length, BF_KEY *schedule, unsigned char *ivec, int *num); |
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23 | const char *BF_options(void); |
24 | ||
c15602f4 RL |
25 | void BF_encrypt(BF_LONG *data,const BF_KEY *key); |
26 | void BF_decrypt(BF_LONG *data,const BF_KEY *key); | |
8fdec3e5 | 27 | |
9dd2b2a9 RL |
28 | =head1 DESCRIPTION |
29 | ||
6ce46d69 | 30 | This library implements the Blowfish cipher, which was invented and described |
447a9638 | 31 | by Counterpane (see http://www.counterpane.com/blowfish.html ). |
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32 | |
33 | Blowfish is a block cipher that operates on 64 bit (8 byte) blocks of data. | |
34 | It uses a variable size key, but typically, 128 bit (16 byte) keys are | |
5286db69 | 35 | considered good for strong encryption. Blowfish can be used in the same |
9b86974e | 36 | modes as DES (see L<des_modes(7)>). Blowfish is currently one |
9dd2b2a9 RL |
37 | of the faster block ciphers. It is quite a bit faster than DES, and much |
38 | faster than IDEA or RC2. | |
39 | ||
40 | Blowfish consists of a key setup phase and the actual encryption or decryption | |
41 | phase. | |
42 | ||
43 | BF_set_key() sets up the B<BF_KEY> B<key> using the B<len> bytes long key | |
44 | at B<data>. | |
45 | ||
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46 | BF_ecb_encrypt() is the basic Blowfish encryption and decryption function. |
47 | It encrypts or decrypts the first 64 bits of B<in> using the key B<key>, | |
48 | putting the result in B<out>. B<enc> decides if encryption (B<BF_ENCRYPT>) | |
49 | or decryption (B<BF_DECRYPT>) shall be performed. The vector pointed at by | |
50 | B<in> and B<out> must be 64 bits in length, no less. If they are larger, | |
51 | everything after the first 64 bits is ignored. | |
52 | ||
53 | The mode functions BF_cbc_encrypt(), BF_cfb64_encrypt() and BF_ofb64_encrypt() | |
c8973693 | 54 | all operate on variable length data. They all take an initialization vector |
1bc74519 | 55 | B<ivec> which needs to be passed along into the next call of the same function |
c8973693 UM |
56 | for the same message. B<ivec> may be initialized with anything, but the |
57 | recipient needs to know what it was initialized with, or it won't be able | |
1bb30673 | 58 | to decrypt. Some programs and protocols simplify this, like SSH, where |
c8973693 | 59 | B<ivec> is simply initialized to zero. |
6ce46d69 | 60 | BF_cbc_encrypt() operates on data that is a multiple of 8 bytes long, while |
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61 | BF_cfb64_encrypt() and BF_ofb64_encrypt() are used to encrypt an variable |
62 | number of bytes (the amount does not have to be an exact multiple of 8). The | |
63 | purpose of the latter two is to simulate stream ciphers, and therefore, they | |
64 | need the parameter B<num>, which is a pointer to an integer where the current | |
c8973693 UM |
65 | offset in B<ivec> is stored between calls. This integer must be initialized |
66 | to zero when B<ivec> is initialized. | |
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67 | |
68 | BF_cbc_encrypt() is the Cipher Block Chaining function for Blowfish. It | |
69 | encrypts or decrypts the 64 bits chunks of B<in> using the key B<schedule>, | |
70 | putting the result in B<out>. B<enc> decides if encryption (BF_ENCRYPT) or | |
71 | decryption (BF_DECRYPT) shall be performed. B<ivec> must point at an 8 byte | |
c8973693 | 72 | long initialization vector. |
9dd2b2a9 RL |
73 | |
74 | BF_cfb64_encrypt() is the CFB mode for Blowfish with 64 bit feedback. | |
75 | It encrypts or decrypts the bytes in B<in> using the key B<schedule>, | |
76 | putting the result in B<out>. B<enc> decides if encryption (B<BF_ENCRYPT>) | |
77 | or decryption (B<BF_DECRYPT>) shall be performed. B<ivec> must point at an | |
c8973693 | 78 | 8 byte long initialization vector. B<num> must point at an integer which must |
1bb30673 | 79 | be initially zero. |
9dd2b2a9 RL |
80 | |
81 | BF_ofb64_encrypt() is the OFB mode for Blowfish with 64 bit feedback. | |
c8973693 | 82 | It uses the same parameters as BF_cfb64_encrypt(), which must be initialized |
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83 | the same way. |
84 | ||
c15602f4 RL |
85 | BF_encrypt() and BF_decrypt() are the lowest level functions for Blowfish |
86 | encryption. They encrypt/decrypt the first 64 bits of the vector pointed by | |
87 | B<data>, using the key B<key>. These functions should not be used unless you | |
88 | implement 'modes' of Blowfish. The alternative is to use BF_ecb_encrypt(). | |
89 | If you still want to use these functions, you should be aware that they take | |
90 | each 32-bit chunk in host-byte order, which is little-endian on little-endian | |
91 | platforms and big-endian on big-endian ones. | |
92 | ||
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93 | =head1 RETURN VALUES |
94 | ||
95 | None of the functions presented here return any value. | |
96 | ||
97 | =head1 NOTE | |
98 | ||
d52c9734 | 99 | Applications should use the higher level functions |
9b86974e | 100 | L<EVP_EncryptInit(3)> etc. instead of calling these |
c7497f34 | 101 | functions directly. |
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102 | |
103 | =head1 SEE ALSO | |
104 | ||
9b86974e RS |
105 | L<EVP_EncryptInit(3)>, |
106 | L<des_modes(7)> | |
9dd2b2a9 | 107 | |
9dd2b2a9 | 108 | =cut |
e2f92610 RS |
109 | |
110 | =head1 COPYRIGHT | |
111 | ||
112 | Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved. | |
113 | ||
114 | Licensed under the OpenSSL license (the "License"). You may not use | |
115 | this file except in compliance with the License. You can obtain a copy | |
116 | in the file LICENSE in the source distribution or at | |
117 | L<https://www.openssl.org/source/license.html>. | |
118 | ||
119 | =cut |