1 =pod 2 3 =head1 NAME 4 5 des_random_key, des_set_key, des_key_sched, des_set_key_checked, 6 des_set_key_unchecked, des_set_odd_parity, des_is_weak_key, 7 des_ecb_encrypt, des_ecb2_encrypt, des_ecb3_encrypt, des_ncbc_encrypt, 8 des_cfb_encrypt, des_ofb_encrypt, des_pcbc_encrypt, des_cfb64_encrypt, 9 des_ofb64_encrypt, des_xcbc_encrypt, des_ede2_cbc_encrypt, 10 des_ede2_cfb64_encrypt, des_ede2_ofb64_encrypt, des_ede3_cbc_encrypt, 11 des_ede3_cbcm_encrypt, des_ede3_cfb64_encrypt, des_ede3_ofb64_encrypt, 12 des_read_password, des_read_2passwords, des_read_pw_string, 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 16 =head1 SYNOPSIS 17 18 #include <openssl/des.h> 19 20 void des_random_key(des_cblock *ret); 21 22 int des_set_key(const_des_cblock *key, des_key_schedule schedule); 23 int des_key_sched(const_des_cblock *key, des_key_schedule schedule); 24 int des_set_key_checked(const_des_cblock *key, 25 des_key_schedule schedule); 26 void des_set_key_unchecked(const_des_cblock *key, 27 des_key_schedule schedule); 28 29 void des_set_odd_parity(des_cblock *key); 30 int des_is_weak_key(const_des_cblock *key); 31 32 void des_ecb_encrypt(const_des_cblock *input, des_cblock *output, 33 des_key_schedule ks, int enc); 34 void des_ecb2_encrypt(const_des_cblock *input, des_cblock *output, 35 des_key_schedule ks1, des_key_schedule ks2, int enc); 36 void des_ecb3_encrypt(const_des_cblock *input, des_cblock *output, 37 des_key_schedule ks1, des_key_schedule ks2, 38 des_key_schedule ks3, int enc); 39 40 void des_ncbc_encrypt(const unsigned char *input, unsigned char *output, 41 long length, des_key_schedule schedule, des_cblock *ivec, 42 int enc); 43 void des_cfb_encrypt(const unsigned char *in, unsigned char *out, 44 int numbits, long length, des_key_schedule schedule, 45 des_cblock *ivec, int enc); 46 void des_ofb_encrypt(const unsigned char *in, unsigned char *out, 47 int numbits, long length, des_key_schedule schedule, 48 des_cblock *ivec); 49 void des_pcbc_encrypt(const unsigned char *input, unsigned char *output, 50 long length, des_key_schedule schedule, des_cblock *ivec, 51 int enc); 52 void des_cfb64_encrypt(const unsigned char *in, unsigned char *out, 53 long length, des_key_schedule schedule, des_cblock *ivec, 54 int *num, int enc); 55 void des_ofb64_encrypt(const unsigned char *in, unsigned char *out, 56 long length, des_key_schedule schedule, des_cblock *ivec, 57 int *num); 58 59 void des_xcbc_encrypt(const unsigned char *input, unsigned char *output, 60 long length, des_key_schedule schedule, des_cblock *ivec, 61 const_des_cblock *inw, const_des_cblock *outw, int enc); 62 63 void des_ede2_cbc_encrypt(const unsigned char *input, 64 unsigned char *output, long length, des_key_schedule ks1, 65 des_key_schedule ks2, des_cblock *ivec, int enc); 66 void des_ede2_cfb64_encrypt(const unsigned char *in, 67 unsigned char *out, long length, des_key_schedule ks1, 68 des_key_schedule ks2, des_cblock *ivec, int *num, int enc); 69 void des_ede2_ofb64_encrypt(const unsigned char *in, 70 unsigned char *out, long length, des_key_schedule ks1, 71 des_key_schedule ks2, des_cblock *ivec, int *num); 72 73 void des_ede3_cbc_encrypt(const unsigned char *input, 74 unsigned char *output, long length, des_key_schedule ks1, 75 des_key_schedule ks2, des_key_schedule ks3, des_cblock *ivec, 76 int enc); 77 void des_ede3_cbcm_encrypt(const unsigned char *in, unsigned char *out, 78 long length, des_key_schedule ks1, des_key_schedule ks2, 79 des_key_schedule ks3, des_cblock *ivec1, des_cblock *ivec2, 80 int enc); 81 void des_ede3_cfb64_encrypt(const unsigned char *in, unsigned char *out, 82 long length, des_key_schedule ks1, des_key_schedule ks2, 83 des_key_schedule ks3, des_cblock *ivec, int *num, int enc); 84 void des_ede3_ofb64_encrypt(const unsigned char *in, unsigned char *out, 85 long length, des_key_schedule ks1, 86 des_key_schedule ks2, des_key_schedule ks3, 87 des_cblock *ivec, int *num); 88 89 int des_read_password(des_cblock *key, const char *prompt, int verify); 90 int des_read_2passwords(des_cblock *key1, des_cblock *key2, 91 const char *prompt, int verify); 92 int des_read_pw_string(char *buf, int length, const char *prompt, 93 int verify); 94 95 DES_LONG des_cbc_cksum(const unsigned char *input, des_cblock *output, 96 long length, des_key_schedule schedule, 97 const_des_cblock *ivec); 98 DES_LONG des_quad_cksum(const unsigned char *input, des_cblock output[], 99 long length, int out_count, des_cblock *seed); 100 void des_string_to_key(const char *str, des_cblock *key); 101 void des_string_to_2keys(const char *str, des_cblock *key1, 102 des_cblock *key2); 103 104 char *des_fcrypt(const char *buf, const char *salt, char *ret); 105 char *des_crypt(const char *buf, const char *salt); 106 char *crypt(const char *buf, const char *salt); 107 108 int des_enc_read(int fd, void *buf, int len, des_key_schedule sched, 109 des_cblock *iv); 110 int des_enc_write(int fd, const void *buf, int len, 111 des_key_schedule sched, des_cblock *iv); 112 113 =head1 DESCRIPTION 114 115 This library contains a fast implementation of the DES encryption 116 algorithm. 117 118 There are two phases to the use of DES encryption. The first is the 119 generation of a I<des_key_schedule> from a key, the second is the 120 actual encryption. A DES key is of type I<des_cblock>. This type is 121 consists of 8 bytes with odd parity. The least significant bit in 122 each byte is the parity bit. The key schedule is an expanded form of 123 the key; it is used to speed the encryption process. 124 125 des_random_key() generates a random key. The PRNG must be seeded 126 prior to using this function (see L<rand(3)|rand(3)>; for backward 127 compatibility the function des_random_seed() is available as well). 128 If the PRNG could not generate a secure key, 0 is returned. In 129 earlier versions of the library, des_random_key() did not generate 130 secure keys. 131 132 Before a DES key can be used, it must be converted into the 133 architecture dependent I<des_key_schedule> via the 134 des_set_key_checked() or des_set_key_unchecked() function. 135 136 des_set_key_checked() will check that the key passed is of odd parity 137 and is not a week or semi-weak key. If the parity is wrong, then -1 138 is returned. If the key is a weak key, then -2 is returned. If an 139 error is returned, the key schedule is not generated. 140 141 des_set_key() (called des_key_sched() in the MIT library) works like 142 des_set_key_checked() if the I<des_check_key> flag is non-zero, 143 otherwise like des_set_key_unchecked(). These functions are available 144 for compatibility; it is recommended to use a function that does not 145 depend on a global variable. 146 147 des_set_odd_parity() (called des_fixup_key_parity() in the MIT 148 library) sets the parity of the passed I<key> to odd. 149 150 des_is_weak_key() returns 1 is the passed key is a weak key, 0 if it 151 is ok. The probability that a randomly generated key is weak is 152 1/2^52, so it is not really worth checking for them. 153 154 The following routines mostly operate on an input and output stream of 155 I<des_cblock>s. 156 157 des_ecb_encrypt() is the basic DES encryption routine that encrypts or 158 decrypts a single 8-byte I<des_cblock> in I<electronic code book> 159 (ECB) mode. It always transforms the input data, pointed to by 160 I<input>, into the output data, pointed to by the I<output> argument. 161 If the I<encrypt> argument is non-zero (DES_ENCRYPT), the I<input> 162 (cleartext) is encrypted in to the I<output> (ciphertext) using the 163 key_schedule specified by the I<schedule> argument, previously set via 164 I<des_set_key>. If I<encrypt> is zero (DES_DECRYPT), the I<input> (now 165 ciphertext) is decrypted into the I<output> (now cleartext). Input 166 and output may overlap. des_ecb_encrypt() does not return a value. 167 168 des_ecb3_encrypt() encrypts/decrypts the I<input> block by using 169 three-key Triple-DES encryption in ECB mode. This involves encrypting 170 the input with I<ks1>, decrypting with the key schedule I<ks2>, and 171 then encrypting with I<ks3>. This routine greatly reduces the chances 172 of brute force breaking of DES and has the advantage of if I<ks1>, 173 I<ks2> and I<ks3> are the same, it is equivalent to just encryption 174 using ECB mode and I<ks1> as the key. 175 176 The macro des_ecb2_encrypt() is provided to perform two-key Triple-DES 177 encryption by using I<ks1> for the final encryption. 178 179 des_ncbc_encrypt() encrypts/decrypts using the I<cipher-block-chaining> 180 (CBC) mode of DES. If the I<encrypt> argument is non-zero, the 181 routine cipher-block-chain encrypts the cleartext data pointed to by 182 the I<input> argument into the ciphertext pointed to by the I<output> 183 argument, using the key schedule provided by the I<schedule> argument, 184 and initialization vector provided by the I<ivec> argument. If the 185 I<length> argument is not an integral multiple of eight bytes, the 186 last block is copied to a temporary area and zero filled. The output 187 is always an integral multiple of eight bytes. 188 189 des_xcbc_encrypt() is RSA's DESX mode of DES. It uses I<inw> and 190 I<outw> to 'whiten' the encryption. I<inw> and I<outw> are secret 191 (unlike the iv) and are as such, part of the key. So the key is sort 192 of 24 bytes. This is much better than CBC DES. 193 194 des_ede3_cbc_encrypt() implements outer triple CBC DES encryption with 195 three keys. This means that each DES operation inside the CBC mode is 196 really an C<C=E(ks3,D(ks2,E(ks1,M)))>. This mode is used by SSL. 197 198 The des_ede2_cbc_encrypt() macro implements two-key Triple-DES by 199 reusing I<ks1> for the final encryption. C<C=E(ks1,D(ks2,E(ks1,M)))>. 200 This form of Triple-DES is used by the RSAREF library. 201 202 des_pcbc_encrypt() encrypt/decrypts using the propagating cipher block 203 chaining mode used by Kerberos v4. Its parameters are the same as 204 des_ncbc_encrypt(). 205 206 des_cfb_encrypt() encrypt/decrypts using cipher feedback mode. This 207 method takes an array of characters as input and outputs and array of 208 characters. It does not require any padding to 8 character groups. 209 Note: the I<ivec> variable is changed and the new changed value needs to 210 be passed to the next call to this function. Since this function runs 211 a complete DES ECB encryption per I<numbits>, this function is only 212 suggested for use when sending small numbers of characters. 213 214 des_cfb64_encrypt() 215 implements CFB mode of DES with 64bit feedback. Why is this 216 useful you ask? Because this routine will allow you to encrypt an 217 arbitrary number of bytes, no 8 byte padding. Each call to this 218 routine will encrypt the input bytes to output and then update ivec 219 and num. num contains 'how far' we are though ivec. If this does 220 not make much sense, read more about cfb mode of DES :-). 221 222 des_ede3_cfb64_encrypt() and des_ede2_cfb64_encrypt() is the same as 223 des_cfb64_encrypt() except that Triple-DES is used. 224 225 des_ofb_encrypt() encrypts using output feedback mode. This method 226 takes an array of characters as input and outputs and array of 227 characters. It does not require any padding to 8 character groups. 228 Note: the I<ivec> variable is changed and the new changed value needs to 229 be passed to the next call to this function. Since this function runs 230 a complete DES ECB encryption per numbits, this function is only 231 suggested for use when sending small numbers of characters. 232 233 des_ofb64_encrypt() is the same as des_cfb64_encrypt() using Output 234 Feed Back mode. 235 236 des_ede3_ofb64_encrypt() and des_ede2_ofb64_encrypt() is the same as 237 des_ofb64_encrypt(), using Triple-DES. 238 239 The following functions are included in the DES library for 240 compatibility with the MIT Kerberos library. des_read_pw_string() 241 is also available under the name EVP_read_pw_string(). 242 243 des_read_pw_string() writes the string specified by I<prompt> to 244 standard output, turns echo off and reads in input string from the 245 terminal. The string is returned in I<buf>, which must have space for 246 at least I<length> bytes. If I<verify> is set, the user is asked for 247 the password twice and unless the two copies match, an error is 248 returned. A return code of -1 indicates a system error, 1 failure due 249 to use interaction, and 0 is success. 250 251 des_read_password() does the same and converts the password to a DES 252 key by calling des_string_to_key(); des_read_2password() operates in 253 the same way as des_read_password() except that it generates two keys 254 by using the des_string_to_2key() function. des_string_to_key() is 255 available for backward compatibility with the MIT library. New 256 applications should use a cryptographic hash function. The same 257 applies for des_string_to_2key(). 258 259 des_cbc_cksum() produces an 8 byte checksum based on the input stream 260 (via CBC encryption). The last 4 bytes of the checksum are returned 261 and the complete 8 bytes are placed in I<output>. This function is 262 used by Kerberos v4. Other applications should use 263 L<EVP_DigestInit(3)|EVP_DigestInit(3)> etc. instead. 264 265 des_quad_cksum() is a Kerberos v4 function. It returns a 4 byte 266 checksum from the input bytes. The algorithm can be iterated over the 267 input, depending on I<out_count>, 1, 2, 3 or 4 times. If I<output> is 268 non-NULL, the 8 bytes generated by each pass are written into 269 I<output>. 270 271 The following are DES-based transformations: 272 273 des_fcrypt() is a fast version of the Unix crypt(3) function. This 274 version takes only a small amount of space relative to other fast 275 crypt() implementations. This is different to the normal crypt in 276 that the third parameter is the buffer that the return value is 277 written into. It needs to be at least 14 bytes long. This function 278 is thread safe, unlike the normal crypt. 279 280 des_crypt() is a faster replacement for the normal system crypt(). 281 This function calls des_fcrypt() with a static array passed as the 282 third parameter. This emulates the normal non-thread safe semantics 283 of crypt(3). 284 285 des_enc_write() writes I<len> bytes to file descriptor I<fd> from 286 buffer I<buf>. The data is encrypted via I<pcbc_encrypt> (default) 287 using I<sched> for the key and I<iv> as a starting vector. The actual 288 data send down I<fd> consists of 4 bytes (in network byte order) 289 containing the length of the following encrypted data. The encrypted 290 data then follows, padded with random data out to a multiple of 8 291 bytes. 292 293 des_enc_read() is used to read I<len> bytes from file descriptor 294 I<fd> into buffer I<buf>. The data being read from I<fd> is assumed to 295 have come from des_enc_write() and is decrypted using I<sched> for 296 the key schedule and I<iv> for the initial vector. 297 298 B<Warning:> The data format used by des_enc_write() and des_enc_read() 299 has a cryptographic weakness: When asked to write more than MAXWRITE 300 bytes, des_enc_write() will split the data into several chunks that 301 are all encrypted using the same IV. So don't use these functions 302 unless you are sure you know what you do (in which case you might not 303 want to use them anyway). They cannot handle non-blocking sockets. 304 des_enc_read() uses an internal state and thus cannot be used on 305 multiple files. 306 307 I<des_rw_mode> is used to specify the encryption mode to use with 308 des_enc_read() and des_end_write(). If set to I<DES_PCBC_MODE> (the 309 default), des_pcbc_encrypt is used. If set to I<DES_CBC_MODE> 310 des_cbc_encrypt is used. 311 312 =head1 NOTES 313 314 Single-key DES is insecure due to its short key size. ECB mode is 315 not suitable for most applications; see L<des_modes(7)|des_modes(7)>. 316 317 The L<evp(3)|evp(3)> library provides higher-level encryption functions. 318 319 =head1 BUGS 320 321 des_3cbc_encrypt() is flawed and must not be used in applications. 322 323 des_cbc_encrypt() does not modify B<ivec>; use des_ncbc_encrypt() 324 instead. 325 326 des_cfb_encrypt() and des_ofb_encrypt() operates on input of 8 bits. 327 What this means is that if you set numbits to 12, and length to 2, the 328 first 12 bits will come from the 1st input byte and the low half of 329 the second input byte. The second 12 bits will have the low 8 bits 330 taken from the 3rd input byte and the top 4 bits taken from the 4th 331 input byte. The same holds for output. This function has been 332 implemented this way because most people will be using a multiple of 8 333 and because once you get into pulling bytes input bytes apart things 334 get ugly! 335 336 des_read_pw_string() is the most machine/OS dependent function and 337 normally generates the most problems when porting this code. 338 339 =head1 CONFORMING TO 340 341 ANSI X3.106 342 343 The B<des> library was written to be source code compatible with 344 the MIT Kerberos library. 345 346 =head1 SEE ALSO 347 348 crypt(3), L<des_modes(7)|des_modes(7)>, L<evp(3)|evp(3)>, L<rand(3)|rand(3)> 349 350 =head1 HISTORY 351 352 des_cbc_cksum(), des_cbc_encrypt(), des_ecb_encrypt(), 353 des_is_weak_key(), des_key_sched(), des_pcbc_encrypt(), 354 des_quad_cksum(), des_random_key(), des_read_password() and 355 des_string_to_key() are available in the MIT Kerberos library; 356 des_check_key_parity(), des_fixup_key_parity() and des_is_weak_key() 357 are available in newer versions of that library. 358 359 des_set_key_checked() and des_set_key_unchecked() were added in 360 OpenSSL 0.9.5. 361 362 des_generate_random_block(), des_init_random_number_generator(), 363 des_new_random_key(), des_set_random_generator_seed() and 364 des_set_sequence_number() and des_rand_data() are used in newer 365 versions of Kerberos but are not implemented here. 366 367 des_random_key() generated cryptographically weak random data in 368 SSLeay and in OpenSSL prior version 0.9.5, as well as in the original 369 MIT library. 370 371 =head1 AUTHOR 372 373 Eric Young (eay (a] cryptsoft.com). Modified for the OpenSSL project 374 (http://www.openssl.org). 375 376 =cut 377
Indexes created Mon Mar 02 05:31:46 UTC 2026