1des(3) OpenSSL des(3)
2
6 DES_random_key, DES_set_key, DES_key_sched, DES_set_key_checked,
7 DES_set_key_unchecked, DES_set_odd_parity, DES_is_weak_key,
8 DES_ecb_encrypt, DES_ecb2_encrypt, DES_ecb3_encrypt, DES_ncbc_encrypt,
9 DES_cfb_encrypt, DES_ofb_encrypt, DES_pcbc_encrypt, DES_cfb64_encrypt,
10 DES_ofb64_encrypt, DES_xcbc_encrypt, DES_ede2_cbc_encrypt,
11 DES_ede2_cfb64_encrypt, DES_ede2_ofb64_encrypt, DES_ede3_cbc_encrypt,
12 DES_ede3_cbcm_encrypt, DES_ede3_cfb64_encrypt, DES_ede3_ofb64_encrypt,
13 DES_cbc_cksum, DES_quad_cksum, DES_string_to_key, DES_string_to_2keys,
14 DES_fcrypt, DES_crypt, DES_enc_read, DES_enc_write - DES encryption
15
17 #include <openssl/des.h>
18 void DES_random_key(DES_cblock *ret);
20 int DES_set_key(const_DES_cblock *key, DES_key_schedule *schedule);
22 int DES_key_sched(const_DES_cblock *key, DES_key_schedule *schedule);
23 int DES_set_key_checked(const_DES_cblock *key,
24 DES_key_schedule *schedule);
25 void DES_set_key_unchecked(const_DES_cblock *key,
26 DES_key_schedule *schedule);
27 void DES_set_odd_parity(DES_cblock *key);
29 int DES_is_weak_key(const_DES_cblock *key);
30 void DES_ecb_encrypt(const_DES_cblock *input, DES_cblock *output,
32 DES_key_schedule *ks, int enc);
33 void DES_ecb2_encrypt(const_DES_cblock *input, DES_cblock *output,
34 DES_key_schedule *ks1, DES_key_schedule *ks2, int enc);
35 void DES_ecb3_encrypt(const_DES_cblock *input, DES_cblock *output,
36 DES_key_schedule *ks1, DES_key_schedule *ks2,
37 DES_key_schedule *ks3, int enc);
38 void DES_ncbc_encrypt(const unsigned char *input, unsigned char *output,
40 long length, DES_key_schedule *schedule, DES_cblock *ivec,
41 int enc);
42 void DES_cfb_encrypt(const unsigned char *in, unsigned char *out,
43 int numbits, long length, DES_key_schedule *schedule,
44 DES_cblock *ivec, int enc);
45 void DES_ofb_encrypt(const unsigned char *in, unsigned char *out,
46 int numbits, long length, DES_key_schedule *schedule,
47 DES_cblock *ivec);
48 void DES_pcbc_encrypt(const unsigned char *input, unsigned char *output,
49 long length, DES_key_schedule *schedule, DES_cblock *ivec,
50 int enc);
51 void DES_cfb64_encrypt(const unsigned char *in, unsigned char *out,
52 long length, DES_key_schedule *schedule, DES_cblock *ivec,
53 int *num, int enc);
54 void DES_ofb64_encrypt(const unsigned char *in, unsigned char *out,
55 long length, DES_key_schedule *schedule, DES_cblock *ivec,
56 int *num);
57 void DES_xcbc_encrypt(const unsigned char *input, unsigned char *output,
59 long length, DES_key_schedule *schedule, DES_cblock *ivec,
60 const_DES_cblock *inw, const_DES_cblock *outw, int enc);
61 void DES_ede2_cbc_encrypt(const unsigned char *input,
63 unsigned char *output, long length, DES_key_schedule *ks1,
64 DES_key_schedule *ks2, DES_cblock *ivec, int enc);
65 void DES_ede2_cfb64_encrypt(const unsigned char *in,
66 unsigned char *out, long length, DES_key_schedule *ks1,
67 DES_key_schedule *ks2, DES_cblock *ivec, int *num, int enc);
68 void DES_ede2_ofb64_encrypt(const unsigned char *in,
69 unsigned char *out, long length, DES_key_schedule *ks1,
70 DES_key_schedule *ks2, DES_cblock *ivec, int *num);
71 void DES_ede3_cbc_encrypt(const unsigned char *input,
73 unsigned char *output, long length, DES_key_schedule *ks1,
74 DES_key_schedule *ks2, DES_key_schedule *ks3, DES_cblock *ivec,
75 int enc);
76 void DES_ede3_cbcm_encrypt(const unsigned char *in, unsigned char *out,
77 long length, DES_key_schedule *ks1, DES_key_schedule *ks2,
78 DES_key_schedule *ks3, DES_cblock *ivec1, DES_cblock *ivec2,
79 int enc);
80 void DES_ede3_cfb64_encrypt(const unsigned char *in, unsigned char *out,
81 long length, DES_key_schedule *ks1, DES_key_schedule *ks2,
82 DES_key_schedule *ks3, 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 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,
95 DES_cblock *key2);
96 char *DES_fcrypt(const char *buf, const char *salt, char *ret);
98 char *DES_crypt(const char *buf, const char *salt);
99 int DES_enc_read(int fd, void *buf, int len, DES_key_schedule *sched,
101 DES_cblock *iv);
102 int DES_enc_write(int fd, const void *buf, int len,
103 DES_key_schedule *sched, DES_cblock *iv);
104
106 This library contains a fast implementation of the DES encryption
107 algorithm.
108 There are two phases to the use of DES encryption. The first is the
110 generation of a DES_key_schedule from a key, the second is the actual
111 encryption. A DES key is of type DES_cblock. This type is consists of
112 8 bytes with odd parity. The least significant bit in each byte is the
113 parity bit. The key schedule is an expanded form of the key; it is
114 used to speed the encryption process.
115 DES_random_key() generates a random key. The PRNG must be seeded prior
117 to using this function (see rand(3)). If the PRNG could not generate a
118 secure key, 0 is returned.
119 Before a DES key can be used, it must be converted into the
121 architecture dependent DES_key_schedule via the DES_set_key_checked()
122 or DES_set_key_unchecked() function.
123 DES_set_key_checked() will check that the key passed is of odd parity
125 and is not a week or semi-weak key. If the parity is wrong, then -1 is
126 returned. If the key is a weak key, then -2 is returned. If an error
127 is returned, the key schedule is not generated.
128 DES_set_key() works like DES_set_key_checked() if the DES_check_key
130 flag is non-zero, otherwise like DES_set_key_unchecked(). These
131 functions are available for compatibility; it is recommended to use a
132 function that does not depend on a global variable.
133 DES_set_odd_parity() sets the parity of the passed key to odd.
135 DES_is_weak_key() returns 1 is the passed key is a weak key, 0 if it is
137 ok. The probability that a randomly generated key is weak is 1/2^52,
138 so it is not really worth checking for them.
139 The following routines mostly operate on an input and output stream of
141 DES_cblocks.
142 DES_ecb_encrypt() is the basic DES encryption routine that encrypts or
144 decrypts a single 8-byte DES_cblock in electronic code book (ECB) mode.
145 It always transforms the input data, pointed to by input, into the
146 output data, pointed to by the output argument. If the encrypt
147 argument is non-zero (DES_ENCRYPT), the input (cleartext) is encrypted
148 in to the output (ciphertext) using the key_schedule specified by the
149 schedule argument, previously set via DES_set_key. If encrypt is zero
150 (DES_DECRYPT), the input (now ciphertext) is decrypted into the output
151 (now cleartext). Input and output may overlap. DES_ecb_encrypt() does
152 not return a value.
153 DES_ecb3_encrypt() encrypts/decrypts the input block by using three-key
155 Triple-DES encryption in ECB mode. This involves encrypting the input
156 with ks1, decrypting with the key schedule ks2, and then encrypting
157 with ks3. This routine greatly reduces the chances of brute force
158 breaking of DES and has the advantage of if ks1, ks2 and ks3 are the
159 same, it is equivalent to just encryption using ECB mode and ks1 as the
160 key.
161 The macro DES_ecb2_encrypt() is provided to perform two-key Triple-DES
163 encryption by using ks1 for the final encryption.
164 DES_ncbc_encrypt() encrypts/decrypts using the cipher-block-chaining
166 (CBC) mode of DES. If the encrypt argument is non-zero, the routine
167 cipher-block-chain encrypts the cleartext data pointed to by the input
168 argument into the ciphertext pointed to by the output argument, using
169 the key schedule provided by the schedule argument, and initialization
170 vector provided by the ivec argument. If the length argument is not an
171 integral multiple of eight bytes, the last block is copied to a
172 temporary area and zero filled. The output is always an integral
173 multiple of eight bytes.
174 DES_xcbc_encrypt() is RSA's DESX mode of DES. It uses inw and outw to
176 'whiten' the encryption. inw and outw are secret (unlike the iv) and
177 are as such, part of the key. So the key is sort of 24 bytes. This is
178 much better than CBC DES.
179 DES_ede3_cbc_encrypt() implements outer triple CBC DES encryption with
181 three keys. This means that each DES operation inside the CBC mode is
182 really an "C=E(ks3,D(ks2,E(ks1,M)))". This mode is used by SSL.
183 The DES_ede2_cbc_encrypt() macro implements two-key Triple-DES by
185 reusing ks1 for the final encryption. "C=E(ks1,D(ks2,E(ks1,M)))".
186 This form of Triple-DES is used by the RSAREF library.
187 DES_pcbc_encrypt() encrypt/decrypts using the propagating cipher block
189 chaining mode used by Kerberos v4. Its parameters are the same as
190 DES_ncbc_encrypt().
191 DES_cfb_encrypt() encrypt/decrypts using cipher feedback mode. This
193 method takes an array of characters as input and outputs and array of
194 characters. It does not require any padding to 8 character groups.
195 Note: the ivec variable is changed and the new changed value needs to
196 be passed to the next call to this function. Since this function runs
197 a complete DES ECB encryption per numbits, this function is only
198 suggested for use when sending small numbers of characters.
199 DES_cfb64_encrypt() implements CFB mode of DES with 64bit feedback.
201 Why is this useful you ask? Because this routine will allow you to
202 encrypt an arbitrary number of bytes, no 8 byte padding. Each call to
203 this routine will encrypt the input bytes to output and then update
204 ivec and num. num contains 'how far' we are though ivec. If this does
205 not make much sense, read more about cfb mode of DES :-).
206 DES_ede3_cfb64_encrypt() and DES_ede2_cfb64_encrypt() is the same as
208 DES_cfb64_encrypt() except that Triple-DES is used.
209 DES_ofb_encrypt() encrypts using output feedback mode. This method
211 takes an array of characters as input and outputs and array of
212 characters. It does not require any padding to 8 character groups.
213 Note: the ivec variable is changed and the new changed value needs to
214 be passed to the next call to this function. Since this function runs
215 a complete DES ECB encryption per numbits, this function is only
216 suggested for use when sending small numbers of characters.
217 DES_ofb64_encrypt() is the same as DES_cfb64_encrypt() using Output
219 Feed Back mode.
220 DES_ede3_ofb64_encrypt() and DES_ede2_ofb64_encrypt() is the same as
222 DES_ofb64_encrypt(), using Triple-DES.
223 The following functions are included in the DES library for
225 compatibility with the MIT Kerberos library.
226 DES_cbc_cksum() produces an 8 byte checksum based on the input stream
228 (via CBC encryption). The last 4 bytes of the checksum are returned
229 and the complete 8 bytes are placed in output. This function is used by
230 Kerberos v4. Other applications should use EVP_DigestInit(3) etc.
231 instead.
232 DES_quad_cksum() is a Kerberos v4 function. It returns a 4 byte
234 checksum from the input bytes. The algorithm can be iterated over the
235 input, depending on out_count, 1, 2, 3 or 4 times. If output is non-
236 NULL, the 8 bytes generated by each pass are written into output.
237 The following are DES-based transformations:
239 DES_fcrypt() is a fast version of the Unix crypt(3) function. This
241 version takes only a small amount of space relative to other fast
242 crypt() implementations. This is different to the normal crypt in that
243 the third parameter is the buffer that the return value is written
244 into. It needs to be at least 14 bytes long. This function is thread
245 safe, unlike the normal crypt.
246 DES_crypt() is a faster replacement for the normal system crypt().
248 This function calls DES_fcrypt() with a static array passed as the
249 third parameter. This emulates the normal non-thread safe semantics of
250 crypt(3).
251 DES_enc_write() writes len bytes to file descriptor fd from buffer buf.
253 The data is encrypted via pcbc_encrypt (default) using sched for the
254 key and iv as a starting vector. The actual data send down fd consists
255 of 4 bytes (in network byte order) containing the length of the
256 following encrypted data. The encrypted data then follows, padded with
257 random data out to a multiple of 8 bytes.
258 DES_enc_read() is used to read len bytes from file descriptor fd into
260 buffer buf. The data being read from fd is assumed to have come from
261 DES_enc_write() and is decrypted using sched for the key schedule and
262 iv for the initial vector.
263 Warning: The data format used by DES_enc_write() and DES_enc_read() has
265 a cryptographic weakness: When asked to write more than MAXWRITE bytes,
266 DES_enc_write() will split the data into several chunks that are all
267 encrypted using the same IV. So don't use these functions unless you
268 are sure you know what you do (in which case you might not want to use
269 them anyway). They cannot handle non-blocking sockets. DES_enc_read()
270 uses an internal state and thus cannot be used on multiple files.
271 DES_rw_mode is used to specify the encryption mode to use with
273 DES_enc_read() and DES_end_write(). If set to DES_PCBC_MODE (the
274 default), DES_pcbc_encrypt is used. If set to DES_CBC_MODE
275 DES_cbc_encrypt is used.
276
278 Single-key DES is insecure due to its short key size. ECB mode is not
279 suitable for most applications; see des_modes(7).
280 The evp(3) library provides higher-level encryption functions.
282
284 DES_3cbc_encrypt() is flawed and must not be used in applications.
285 DES_cbc_encrypt() does not modify ivec; use DES_ncbc_encrypt() instead.
287 DES_cfb_encrypt() and DES_ofb_encrypt() operates on input of 8 bits.
289 What this means is that if you set numbits to 12, and length to 2, the
290 first 12 bits will come from the 1st input byte and the low half of the
291 second input byte. The second 12 bits will have the low 8 bits taken
292 from the 3rd input byte and the top 4 bits taken from the 4th input
293 byte. The same holds for output. This function has been implemented
294 this way because most people will be using a multiple of 8 and because
295 once you get into pulling bytes input bytes apart things get ugly!
296 DES_string_to_key() is available for backward compatibility with the
298 MIT library. New applications should use a cryptographic hash
299 function. The same applies for DES_string_to_2key().
300
302 ANSI X3.106
303 The des library was written to be source code compatible with the MIT
305 Kerberos library.
306
308 crypt(3), des_modes(7), evp(3), rand(3)
309
311 In OpenSSL 0.9.7, all des_ functions were renamed to DES_ to avoid
312 clashes with older versions of libdes. Compatibility des_ functions
313 are provided for a short while, as well as crypt(). Declarations for
314 these are in <openssl/des_old.h>. There is no DES_ variant for
315 des_random_seed(). This will happen to other functions as well if they
316 are deemed redundant (des_random_seed() just calls RAND_seed() and is
317 present for backward compatibility only), buggy or already scheduled
318 for removal.
319 des_cbc_cksum(), des_cbc_encrypt(), des_ecb_encrypt(),
321 des_is_weak_key(), des_key_sched(), des_pcbc_encrypt(),
322 des_quad_cksum(), des_random_key() and des_string_to_key() are
323 available in the MIT Kerberos library; des_check_key_parity(),
324 des_fixup_key_parity() and des_is_weak_key() are available in newer
325 versions of that library.
326 des_set_key_checked() and des_set_key_unchecked() were added in OpenSSL
328 0.9.5.
329 des_generate_random_block(), des_init_random_number_generator(),
331 des_new_random_key(), des_set_random_generator_seed() and
332 des_set_sequence_number() and des_rand_data() are used in newer
333 versions of Kerberos but are not implemented here.
334 des_random_key() generated cryptographically weak random data in SSLeay
336 and in OpenSSL prior version 0.9.5, as well as in the original MIT
337 library.
338
340 Eric Young (eay@cryptsoft.com). Modified for the OpenSSL project
341 (http://www.openssl.org).
3421.0.0e 2003-10-01 des(3)