xref: /freebsd/crypto/openssl/doc/man3/BF_encrypt.pod (revision 7ef62cebc2f965b0f640263e179276928885e33d)
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
12The following functions have been deprecated since OpenSSL 3.0, and can be
13hidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value,
14see L<openssl_user_macros(7)>:
15
16 void BF_set_key(BF_KEY *key, int len, const unsigned char *data);
17
18 void BF_ecb_encrypt(const unsigned char *in, unsigned char *out,
19                     BF_KEY *key, int enc);
20 void BF_cbc_encrypt(const unsigned char *in, unsigned char *out,
21                     long length, BF_KEY *schedule,
22                     unsigned char *ivec, int enc);
23 void BF_cfb64_encrypt(const unsigned char *in, unsigned char *out,
24                       long length, BF_KEY *schedule,
25                       unsigned char *ivec, int *num, int enc);
26 void BF_ofb64_encrypt(const unsigned char *in, unsigned char *out,
27                       long length, BF_KEY *schedule,
28                       unsigned char *ivec, int *num);
29 const char *BF_options(void);
30
31 void BF_encrypt(BF_LONG *data, const BF_KEY *key);
32 void BF_decrypt(BF_LONG *data, const BF_KEY *key);
33
34=head1 DESCRIPTION
35
36All of the functions described on this page are deprecated. Applications should
37instead use L<EVP_EncryptInit_ex(3)>, L<EVP_EncryptUpdate(3)> and
38L<EVP_EncryptFinal_ex(3)> or the equivalently named decrypt functions.
39
40This library implements the Blowfish cipher, which was invented and described
41by Counterpane (see http://www.counterpane.com/blowfish.html ).
42
43Blowfish is a block cipher that operates on 64 bit (8 byte) blocks of data.
44It uses a variable size key, but typically, 128 bit (16 byte) keys are
45considered good for strong encryption.  Blowfish can be used in the same
46modes as DES (see L<des_modes(7)>).  Blowfish is currently one
47of the faster block ciphers.  It is quite a bit faster than DES, and much
48faster than IDEA or RC2.
49
50Blowfish consists of a key setup phase and the actual encryption or decryption
51phase.
52
53BF_set_key() sets up the B<BF_KEY> B<key> using the B<len> bytes long key
54at B<data>.
55
56BF_ecb_encrypt() is the basic Blowfish encryption and decryption function.
57It encrypts or decrypts the first 64 bits of B<in> using the key B<key>,
58putting the result in B<out>.  B<enc> decides if encryption (B<BF_ENCRYPT>)
59or decryption (B<BF_DECRYPT>) shall be performed.  The vector pointed at by
60B<in> and B<out> must be 64 bits in length, no less.  If they are larger,
61everything after the first 64 bits is ignored.
62
63The mode functions BF_cbc_encrypt(), BF_cfb64_encrypt() and BF_ofb64_encrypt()
64all operate on variable length data.  They all take an initialization vector
65B<ivec> which needs to be passed along into the next call of the same function
66for the same message.  B<ivec> may be initialized with anything, but the
67recipient needs to know what it was initialized with, or it won't be able
68to decrypt.  Some programs and protocols simplify this, like SSH, where
69B<ivec> is simply initialized to zero.
70BF_cbc_encrypt() operates on data that is a multiple of 8 bytes long, while
71BF_cfb64_encrypt() and BF_ofb64_encrypt() are used to encrypt a variable
72number of bytes (the amount does not have to be an exact multiple of 8).  The
73purpose of the latter two is to simulate stream ciphers, and therefore, they
74need the parameter B<num>, which is a pointer to an integer where the current
75offset in B<ivec> is stored between calls.  This integer must be initialized
76to zero when B<ivec> is initialized.
77
78BF_cbc_encrypt() is the Cipher Block Chaining function for Blowfish.  It
79encrypts or decrypts the 64 bits chunks of B<in> using the key B<schedule>,
80putting the result in B<out>.  B<enc> decides if encryption (BF_ENCRYPT) or
81decryption (BF_DECRYPT) shall be performed.  B<ivec> must point at an 8 byte
82long initialization vector.
83
84BF_cfb64_encrypt() is the CFB mode for Blowfish with 64 bit feedback.
85It encrypts or decrypts the bytes in B<in> using the key B<schedule>,
86putting the result in B<out>.  B<enc> decides if encryption (B<BF_ENCRYPT>)
87or decryption (B<BF_DECRYPT>) shall be performed.  B<ivec> must point at an
888 byte long initialization vector. B<num> must point at an integer which must
89be initially zero.
90
91BF_ofb64_encrypt() is the OFB mode for Blowfish with 64 bit feedback.
92It uses the same parameters as BF_cfb64_encrypt(), which must be initialized
93the same way.
94
95BF_encrypt() and BF_decrypt() are the lowest level functions for Blowfish
96encryption.  They encrypt/decrypt the first 64 bits of the vector pointed by
97B<data>, using the key B<key>.  These functions should not be used unless you
98implement 'modes' of Blowfish.  The alternative is to use BF_ecb_encrypt().
99If you still want to use these functions, you should be aware that they take
100each 32-bit chunk in host-byte order, which is little-endian on little-endian
101platforms and big-endian on big-endian ones.
102
103=head1 RETURN VALUES
104
105None of the functions presented here return any value.
106
107=head1 NOTE
108
109Applications should use the higher level functions
110L<EVP_EncryptInit(3)> etc. instead of calling these
111functions directly.
112
113=head1 SEE ALSO
114
115L<EVP_EncryptInit(3)>,
116L<des_modes(7)>
117
118=head1 HISTORY
119
120All of these functions were deprecated in OpenSSL 3.0.
121
122=head1 COPYRIGHT
123
124Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.
125
126Licensed under the Apache License 2.0 (the "License").  You may not use
127this file except in compliance with the License.  You can obtain a copy
128in the file LICENSE in the source distribution or at
129L<https://www.openssl.org/source/license.html>.
130
131=cut
132