1=pod
2
3=head1 NAME
4
5DES_random_key, DES_set_key, DES_key_sched, DES_set_key_checked,
6DES_set_key_unchecked, DES_set_odd_parity, DES_is_weak_key,
7DES_ecb_encrypt, DES_ecb2_encrypt, DES_ecb3_encrypt, DES_ncbc_encrypt,
8DES_cfb_encrypt, DES_ofb_encrypt, DES_pcbc_encrypt, DES_cfb64_encrypt,
9DES_ofb64_encrypt, DES_xcbc_encrypt, DES_ede2_cbc_encrypt,
10DES_ede2_cfb64_encrypt, DES_ede2_ofb64_encrypt, DES_ede3_cbc_encrypt,
11DES_ede3_cfb64_encrypt, DES_ede3_ofb64_encrypt,
12DES_cbc_cksum, DES_quad_cksum, DES_string_to_key, DES_string_to_2keys,
13DES_fcrypt, DES_crypt - DES encryption
14
15=head1 SYNOPSIS
16
17 #include <openssl/des.h>
18
19The following functions have been deprecated since OpenSSL 3.0, and can be
20hidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value,
21see L<openssl_user_macros(7)>:
22
23 void DES_random_key(DES_cblock *ret);
24
25 int DES_set_key(const_DES_cblock *key, DES_key_schedule *schedule);
26 int DES_key_sched(const_DES_cblock *key, DES_key_schedule *schedule);
27 int DES_set_key_checked(const_DES_cblock *key, DES_key_schedule *schedule);
28 void DES_set_key_unchecked(const_DES_cblock *key, DES_key_schedule *schedule);
29
30 void DES_set_odd_parity(DES_cblock *key);
31 int DES_is_weak_key(const_DES_cblock *key);
32
33 void DES_ecb_encrypt(const_DES_cblock *input, DES_cblock *output,
34                      DES_key_schedule *ks, int enc);
35 void DES_ecb2_encrypt(const_DES_cblock *input, DES_cblock *output,
36                       DES_key_schedule *ks1, DES_key_schedule *ks2, int enc);
37 void DES_ecb3_encrypt(const_DES_cblock *input, DES_cblock *output,
38                       DES_key_schedule *ks1, DES_key_schedule *ks2,
39                       DES_key_schedule *ks3, int enc);
40
41 void DES_ncbc_encrypt(const unsigned char *input, unsigned char *output,
42                       long length, DES_key_schedule *schedule, DES_cblock *ivec,
43                       int enc);
44 void DES_cfb_encrypt(const unsigned char *in, unsigned char *out,
45                      int numbits, long length, DES_key_schedule *schedule,
46                      DES_cblock *ivec, int enc);
47 void DES_ofb_encrypt(const unsigned char *in, unsigned char *out,
48                      int numbits, long length, DES_key_schedule *schedule,
49                      DES_cblock *ivec);
50 void DES_pcbc_encrypt(const unsigned char *input, unsigned char *output,
51                       long length, DES_key_schedule *schedule, DES_cblock *ivec,
52                       int enc);
53 void DES_cfb64_encrypt(const unsigned char *in, unsigned char *out,
54                        long length, DES_key_schedule *schedule, DES_cblock *ivec,
55                        int *num, int enc);
56 void DES_ofb64_encrypt(const unsigned char *in, unsigned char *out,
57                        long length, DES_key_schedule *schedule, DES_cblock *ivec,
58                        int *num);
59
60 void DES_xcbc_encrypt(const unsigned char *input, unsigned char *output,
61                       long length, DES_key_schedule *schedule, DES_cblock *ivec,
62                       const_DES_cblock *inw, const_DES_cblock *outw, int enc);
63
64 void DES_ede2_cbc_encrypt(const unsigned char *input, unsigned char *output,
65                           long length, DES_key_schedule *ks1,
66                           DES_key_schedule *ks2, DES_cblock *ivec, int enc);
67 void DES_ede2_cfb64_encrypt(const unsigned char *in, unsigned char *out,
68                             long length, DES_key_schedule *ks1,
69                             DES_key_schedule *ks2, DES_cblock *ivec,
70                             int *num, int enc);
71 void DES_ede2_ofb64_encrypt(const unsigned char *in, unsigned char *out,
72                             long length, DES_key_schedule *ks1,
73                             DES_key_schedule *ks2, DES_cblock *ivec, int *num);
74
75 void DES_ede3_cbc_encrypt(const unsigned char *input, unsigned char *output,
76                           long length, DES_key_schedule *ks1,
77                           DES_key_schedule *ks2, DES_key_schedule *ks3,
78                           DES_cblock *ivec, int enc);
79 void DES_ede3_cfb64_encrypt(const unsigned char *in, unsigned char *out,
80                             long length, DES_key_schedule *ks1,
81                             DES_key_schedule *ks2, DES_key_schedule *ks3,
82                             DES_cblock *ivec, int *num, int enc);
83 void DES_ede3_ofb64_encrypt(const unsigned char *in, unsigned char *out,
84                             long length, DES_key_schedule *ks1,
85                             DES_key_schedule *ks2, DES_key_schedule *ks3,
86                             DES_cblock *ivec, int *num);
87
88 DES_LONG DES_cbc_cksum(const unsigned char *input, DES_cblock *output,
89                        long length, DES_key_schedule *schedule,
90                        const_DES_cblock *ivec);
91 DES_LONG DES_quad_cksum(const unsigned char *input, DES_cblock output[],
92                         long length, int out_count, DES_cblock *seed);
93 void DES_string_to_key(const char *str, DES_cblock *key);
94 void DES_string_to_2keys(const char *str, DES_cblock *key1, DES_cblock *key2);
95
96 char *DES_fcrypt(const char *buf, const char *salt, char *ret);
97 char *DES_crypt(const char *buf, const char *salt);
98
99=head1 DESCRIPTION
100
101All of the functions described on this page are deprecated. Applications should
102instead use L<EVP_EncryptInit_ex(3)>, L<EVP_EncryptUpdate(3)> and
103L<EVP_EncryptFinal_ex(3)> or the equivalently named decrypt functions.
104
105This library contains a fast implementation of the DES encryption
106algorithm.
107
108There are two phases to the use of DES encryption.  The first is the
109generation of a I<DES_key_schedule> from a key, the second is the
110actual encryption.  A DES key is of type I<DES_cblock>. This type
111consists of 8 bytes with odd parity.  The least significant bit in
112each byte is the parity bit.  The key schedule is an expanded form of
113the key; it is used to speed the encryption process.
114
115DES_random_key() generates a random key.  The random generator must be
116seeded when calling this function.
117If the automatic seeding or reseeding of the OpenSSL CSPRNG fails due to
118external circumstances (see L<RAND(7)>), the operation will fail.
119If the function fails, 0 is returned.
120
121Before a DES key can be used, it must be converted into the
122architecture dependent I<DES_key_schedule> via the
123DES_set_key_checked() or DES_set_key_unchecked() function.
124
125DES_set_key_checked() will check that the key passed is of odd parity
126and is not a weak or semi-weak key.  If the parity is wrong, then -1
127is returned.  If the key is a weak key, then -2 is returned.  If an
128error is returned, the key schedule is not generated.
129
130DES_set_key() works like DES_set_key_checked() and remains for
131backward compatibility.
132
133DES_set_odd_parity() sets the parity of the passed I<key> to odd.
134
135DES_is_weak_key() returns 1 if the passed key is a weak key, 0 if it
136is ok.
137
138The following routines mostly operate on an input and output stream of
139I<DES_cblock>s.
140
141DES_ecb_encrypt() is the basic DES encryption routine that encrypts or
142decrypts a single 8-byte I<DES_cblock> in I<electronic code book>
143(ECB) mode.  It always transforms the input data, pointed to by
144I<input>, into the output data, pointed to by the I<output> argument.
145If the I<encrypt> argument is nonzero (DES_ENCRYPT), the I<input>
146(cleartext) is encrypted in to the I<output> (ciphertext) using the
147key_schedule specified by the I<schedule> argument, previously set via
148I<DES_set_key>. If I<encrypt> is zero (DES_DECRYPT), the I<input> (now
149ciphertext) is decrypted into the I<output> (now cleartext).  Input
150and output may overlap.  DES_ecb_encrypt() does not return a value.
151
152DES_ecb3_encrypt() encrypts/decrypts the I<input> block by using
153three-key Triple-DES encryption in ECB mode.  This involves encrypting
154the input with I<ks1>, decrypting with the key schedule I<ks2>, and
155then encrypting with I<ks3>.  This routine greatly reduces the chances
156of brute force breaking of DES and has the advantage of if I<ks1>,
157I<ks2> and I<ks3> are the same, it is equivalent to just encryption
158using ECB mode and I<ks1> as the key.
159
160The macro DES_ecb2_encrypt() is provided to perform two-key Triple-DES
161encryption by using I<ks1> for the final encryption.
162
163DES_ncbc_encrypt() encrypts/decrypts using the I<cipher-block-chaining>
164(CBC) mode of DES.  If the I<encrypt> argument is nonzero, the
165routine cipher-block-chain encrypts the cleartext data pointed to by
166the I<input> argument into the ciphertext pointed to by the I<output>
167argument, using the key schedule provided by the I<schedule> argument,
168and initialization vector provided by the I<ivec> argument.  If the
169I<length> argument is not an integral multiple of eight bytes, the
170last block is copied to a temporary area and zero filled.  The output
171is always an integral multiple of eight bytes.
172
173DES_xcbc_encrypt() is RSA's DESX mode of DES.  It uses I<inw> and
174I<outw> to 'whiten' the encryption.  I<inw> and I<outw> are secret
175(unlike the iv) and are as such, part of the key.  So the key is sort
176of 24 bytes.  This is much better than CBC DES.
177
178DES_ede3_cbc_encrypt() implements outer triple CBC DES encryption with
179three keys. This means that each DES operation inside the CBC mode is
180C<C=E(ks3,D(ks2,E(ks1,M)))>.  This mode is used by SSL.
181
182The DES_ede2_cbc_encrypt() macro implements two-key Triple-DES by
183reusing I<ks1> for the final encryption.  C<C=E(ks1,D(ks2,E(ks1,M)))>.
184This form of Triple-DES is used by the RSAREF library.
185
186DES_pcbc_encrypt() encrypts/decrypts using the propagating cipher block
187chaining mode used by Kerberos v4. Its parameters are the same as
188DES_ncbc_encrypt().
189
190DES_cfb_encrypt() encrypts/decrypts using cipher feedback mode.  This
191method takes an array of characters as input and outputs an array of
192characters.  It does not require any padding to 8 character groups.
193Note: the I<ivec> variable is changed and the new changed value needs to
194be passed to the next call to this function.  Since this function runs
195a complete DES ECB encryption per I<numbits>, this function is only
196suggested for use when sending a small number of characters.
197
198DES_cfb64_encrypt()
199implements CFB mode of DES with 64-bit feedback.  Why is this
200useful you ask?  Because this routine will allow you to encrypt an
201arbitrary number of bytes, without 8 byte padding.  Each call to this
202routine will encrypt the input bytes to output and then update ivec
203and num.  num contains 'how far' we are though ivec.  If this does
204not make much sense, read more about CFB mode of DES.
205
206DES_ede3_cfb64_encrypt() and DES_ede2_cfb64_encrypt() is the same as
207DES_cfb64_encrypt() except that Triple-DES is used.
208
209DES_ofb_encrypt() encrypts using output feedback mode.  This method
210takes an array of characters as input and outputs an array of
211characters.  It does not require any padding to 8 character groups.
212Note: the I<ivec> variable is changed and the new changed value needs to
213be passed to the next call to this function.  Since this function runs
214a complete DES ECB encryption per I<numbits>, this function is only
215suggested for use when sending a small number of characters.
216
217DES_ofb64_encrypt() is the same as DES_cfb64_encrypt() using Output
218Feed Back mode.
219
220DES_ede3_ofb64_encrypt() and DES_ede2_ofb64_encrypt() is the same as
221DES_ofb64_encrypt(), using Triple-DES.
222
223The following functions are included in the DES library for
224compatibility with the MIT Kerberos library.
225
226DES_cbc_cksum() produces an 8 byte checksum based on the input stream
227(via CBC encryption).  The last 4 bytes of the checksum are returned
228and the complete 8 bytes are placed in I<output>. This function is
229used by Kerberos v4.  Other applications should use
230L<EVP_DigestInit(3)> etc. instead.
231
232DES_quad_cksum() is a Kerberos v4 function.  It returns a 4 byte
233checksum from the input bytes.  The algorithm can be iterated over the
234input, depending on I<out_count>, 1, 2, 3 or 4 times.  If I<output> is
235non-NULL, the 8 bytes generated by each pass are written into
236I<output>.
237
238The following are DES-based transformations:
239
240DES_fcrypt() is a fast version of the Unix crypt(3) function.  This
241version takes only a small amount of space relative to other fast
242crypt() implementations.  This is different to the normal crypt() in
243that the third parameter is the buffer that the return value is
244written into.  It needs to be at least 14 bytes long.  This function
245is thread safe, unlike the normal crypt().
246
247DES_crypt() is a faster replacement for the normal system crypt().
248This function calls DES_fcrypt() with a static array passed as the
249third parameter.  This mostly emulates the normal non-thread-safe semantics
250of crypt(3).
251The B<salt> must be two ASCII characters.
252
253The values returned by DES_fcrypt() and DES_crypt() are terminated by NUL
254character.
255
256DES_enc_write() writes I<len> bytes to file descriptor I<fd> from
257buffer I<buf>. The data is encrypted via I<pcbc_encrypt> (default)
258using I<sched> for the key and I<iv> as a starting vector.  The actual
259data send down I<fd> consists of 4 bytes (in network byte order)
260containing the length of the following encrypted data.  The encrypted
261data then follows, padded with random data out to a multiple of 8
262bytes.
263
264=head1 BUGS
265
266DES_cbc_encrypt() does not modify B<ivec>; use DES_ncbc_encrypt()
267instead.
268
269DES_cfb_encrypt() and DES_ofb_encrypt() operates on input of 8 bits.
270What this means is that if you set numbits to 12, and length to 2, the
271first 12 bits will come from the 1st input byte and the low half of
272the second input byte.  The second 12 bits will have the low 8 bits
273taken from the 3rd input byte and the top 4 bits taken from the 4th
274input byte.  The same holds for output.  This function has been
275implemented this way because most people will be using a multiple of 8
276and because once you get into pulling bytes input bytes apart things
277get ugly!
278
279DES_string_to_key() is available for backward compatibility with the
280MIT library.  New applications should use a cryptographic hash function.
281The same applies for DES_string_to_2key().
282
283=head1 NOTES
284
285The B<des> library was written to be source code compatible with
286the MIT Kerberos library.
287
288Applications should use the higher level functions
289L<EVP_EncryptInit(3)> etc. instead of calling these
290functions directly.
291
292Single-key DES is insecure due to its short key size.  ECB mode is
293not suitable for most applications; see L<des_modes(7)>.
294
295=head1 RETURN VALUES
296
297DES_set_key(), DES_key_sched(), and DES_set_key_checked()
298return 0 on success or negative values on error.
299
300DES_is_weak_key() returns 1 if the passed key is a weak key, 0 if it
301is ok.
302
303DES_cbc_cksum() and DES_quad_cksum() return 4-byte integer representing the
304last 4 bytes of the checksum of the input.
305
306DES_fcrypt() returns a pointer to the caller-provided buffer and DES_crypt() -
307to a static buffer on success; otherwise they return NULL.
308
309=head1 SEE ALSO
310
311L<des_modes(7)>,
312L<EVP_EncryptInit(3)>
313
314=head1 HISTORY
315
316All of these functions were deprecated in OpenSSL 3.0.
317
318The requirement that the B<salt> parameter to DES_crypt() and DES_fcrypt()
319be two ASCII characters was first enforced in
320OpenSSL 1.1.0.  Previous versions tried to use the letter uppercase B<A>
321if both character were not present, and could crash when given non-ASCII
322on some platforms.
323
324=head1 COPYRIGHT
325
326Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.
327
328Licensed under the Apache License 2.0 (the "License").  You may not use
329this file except in compliance with the License.  You can obtain a copy
330in the file LICENSE in the source distribution or at
331L<https://www.openssl.org/source/license.html>.
332
333=cut
334