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 19 void DES_random_key(DES_cblock *ret); 20 21 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, DES_key_schedule *schedule); 24 void DES_set_key_unchecked(const_DES_cblock *key, DES_key_schedule *schedule); 25 26 void DES_set_odd_parity(DES_cblock *key); 27 int DES_is_weak_key(const_DES_cblock *key); 28 29 void DES_ecb_encrypt(const_DES_cblock *input, DES_cblock *output, 30 DES_key_schedule *ks, int enc); 31 void DES_ecb2_encrypt(const_DES_cblock *input, DES_cblock *output, 32 DES_key_schedule *ks1, DES_key_schedule *ks2, int enc); 33 void DES_ecb3_encrypt(const_DES_cblock *input, DES_cblock *output, 34 DES_key_schedule *ks1, DES_key_schedule *ks2, 35 DES_key_schedule *ks3, int enc); 36 37 void DES_ncbc_encrypt(const unsigned char *input, unsigned char *output, 38 long length, DES_key_schedule *schedule, DES_cblock *ivec, 39 int enc); 40 void DES_cfb_encrypt(const unsigned char *in, unsigned char *out, 41 int numbits, long length, DES_key_schedule *schedule, 42 DES_cblock *ivec, int enc); 43 void DES_ofb_encrypt(const unsigned char *in, unsigned char *out, 44 int numbits, long length, DES_key_schedule *schedule, 45 DES_cblock *ivec); 46 void DES_pcbc_encrypt(const unsigned char *input, unsigned char *output, 47 long length, DES_key_schedule *schedule, DES_cblock *ivec, 48 int enc); 49 void DES_cfb64_encrypt(const unsigned char *in, unsigned char *out, 50 long length, DES_key_schedule *schedule, DES_cblock *ivec, 51 int *num, int enc); 52 void DES_ofb64_encrypt(const unsigned char *in, unsigned char *out, 53 long length, DES_key_schedule *schedule, DES_cblock *ivec, 54 int *num); 55 56 void DES_xcbc_encrypt(const unsigned char *input, unsigned char *output, 57 long length, DES_key_schedule *schedule, DES_cblock *ivec, 58 const_DES_cblock *inw, const_DES_cblock *outw, int enc); 59 60 void DES_ede2_cbc_encrypt(const unsigned char *input, unsigned char *output, 61 long length, DES_key_schedule *ks1, 62 DES_key_schedule *ks2, DES_cblock *ivec, int enc); 63 void DES_ede2_cfb64_encrypt(const unsigned char *in, unsigned char *out, 64 long length, DES_key_schedule *ks1, 65 DES_key_schedule *ks2, DES_cblock *ivec, 66 int *num, int enc); 67 void DES_ede2_ofb64_encrypt(const unsigned char *in, unsigned char *out, 68 long length, DES_key_schedule *ks1, 69 DES_key_schedule *ks2, DES_cblock *ivec, int *num); 70 71 void DES_ede3_cbc_encrypt(const unsigned char *input, unsigned char *output, 72 long length, DES_key_schedule *ks1, 73 DES_key_schedule *ks2, DES_key_schedule *ks3, 74 DES_cblock *ivec, int enc); 75 void DES_ede3_cfb64_encrypt(const unsigned char *in, unsigned char *out, 76 long length, DES_key_schedule *ks1, 77 DES_key_schedule *ks2, DES_key_schedule *ks3, 78 DES_cblock *ivec, int *num, int enc); 79 void DES_ede3_ofb64_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); 83 84 DES_LONG DES_cbc_cksum(const unsigned char *input, DES_cblock *output, 85 long length, DES_key_schedule *schedule, 86 const_DES_cblock *ivec); 87 DES_LONG DES_quad_cksum(const unsigned char *input, DES_cblock output[], 88 long length, int out_count, DES_cblock *seed); 89 void DES_string_to_key(const char *str, DES_cblock *key); 90 void DES_string_to_2keys(const char *str, DES_cblock *key1, DES_cblock *key2); 91 92 char *DES_fcrypt(const char *buf, const char *salt, char *ret); 93 char *DES_crypt(const char *buf, const char *salt); 94 95=head1 DESCRIPTION 96 97This library contains a fast implementation of the DES encryption 98algorithm. 99 100There are two phases to the use of DES encryption. The first is the 101generation of a I<DES_key_schedule> from a key, the second is the 102actual encryption. A DES key is of type I<DES_cblock>. This type 103consists of 8 bytes with odd parity. The least significant bit in 104each byte is the parity bit. The key schedule is an expanded form of 105the key; it is used to speed the encryption process. 106 107DES_random_key() generates a random key. The random generator must be 108seeded when calling this function. 109If the automatic seeding or reseeding of the OpenSSL CSPRNG fails due to 110external circumstances (see L<RAND(7)>), the operation will fail. 111If the function fails, 0 is returned. 112 113Before a DES key can be used, it must be converted into the 114architecture dependent I<DES_key_schedule> via the 115DES_set_key_checked() or DES_set_key_unchecked() function. 116 117DES_set_key_checked() will check that the key passed is of odd parity 118and is not a weak or semi-weak key. If the parity is wrong, then -1 119is returned. If the key is a weak key, then -2 is returned. If an 120error is returned, the key schedule is not generated. 121 122DES_set_key() works like 123DES_set_key_checked() if the I<DES_check_key> flag is nonzero, 124otherwise like DES_set_key_unchecked(). These functions are available 125for compatibility; it is recommended to use a function that does not 126depend on a global variable. 127 128DES_set_odd_parity() sets the parity of the passed I<key> to odd. 129 130DES_is_weak_key() returns 1 if the passed key is a weak key, 0 if it 131is ok. 132 133The following routines mostly operate on an input and output stream of 134I<DES_cblock>s. 135 136DES_ecb_encrypt() is the basic DES encryption routine that encrypts or 137decrypts a single 8-byte I<DES_cblock> in I<electronic code book> 138(ECB) mode. It always transforms the input data, pointed to by 139I<input>, into the output data, pointed to by the I<output> argument. 140If the I<encrypt> argument is nonzero (DES_ENCRYPT), the I<input> 141(cleartext) is encrypted in to the I<output> (ciphertext) using the 142key_schedule specified by the I<schedule> argument, previously set via 143I<DES_set_key>. If I<encrypt> is zero (DES_DECRYPT), the I<input> (now 144ciphertext) is decrypted into the I<output> (now cleartext). Input 145and output may overlap. DES_ecb_encrypt() does not return a value. 146 147DES_ecb3_encrypt() encrypts/decrypts the I<input> block by using 148three-key Triple-DES encryption in ECB mode. This involves encrypting 149the input with I<ks1>, decrypting with the key schedule I<ks2>, and 150then encrypting with I<ks3>. This routine greatly reduces the chances 151of brute force breaking of DES and has the advantage of if I<ks1>, 152I<ks2> and I<ks3> are the same, it is equivalent to just encryption 153using ECB mode and I<ks1> as the key. 154 155The macro DES_ecb2_encrypt() is provided to perform two-key Triple-DES 156encryption by using I<ks1> for the final encryption. 157 158DES_ncbc_encrypt() encrypts/decrypts using the I<cipher-block-chaining> 159(CBC) mode of DES. If the I<encrypt> argument is nonzero, the 160routine cipher-block-chain encrypts the cleartext data pointed to by 161the I<input> argument into the ciphertext pointed to by the I<output> 162argument, using the key schedule provided by the I<schedule> argument, 163and initialization vector provided by the I<ivec> argument. If the 164I<length> argument is not an integral multiple of eight bytes, the 165last block is copied to a temporary area and zero filled. The output 166is always an integral multiple of eight bytes. 167 168DES_xcbc_encrypt() is RSA's DESX mode of DES. It uses I<inw> and 169I<outw> to 'whiten' the encryption. I<inw> and I<outw> are secret 170(unlike the iv) and are as such, part of the key. So the key is sort 171of 24 bytes. This is much better than CBC DES. 172 173DES_ede3_cbc_encrypt() implements outer triple CBC DES encryption with 174three keys. This means that each DES operation inside the CBC mode is 175C<C=E(ks3,D(ks2,E(ks1,M)))>. This mode is used by SSL. 176 177The DES_ede2_cbc_encrypt() macro implements two-key Triple-DES by 178reusing I<ks1> for the final encryption. C<C=E(ks1,D(ks2,E(ks1,M)))>. 179This form of Triple-DES is used by the RSAREF library. 180 181DES_pcbc_encrypt() encrypts/decrypts using the propagating cipher block 182chaining mode used by Kerberos v4. Its parameters are the same as 183DES_ncbc_encrypt(). 184 185DES_cfb_encrypt() encrypts/decrypts using cipher feedback mode. This 186method takes an array of characters as input and outputs an array of 187characters. It does not require any padding to 8 character groups. 188Note: the I<ivec> variable is changed and the new changed value needs to 189be passed to the next call to this function. Since this function runs 190a complete DES ECB encryption per I<numbits>, this function is only 191suggested for use when sending a small number of characters. 192 193DES_cfb64_encrypt() 194implements CFB mode of DES with 64-bit feedback. Why is this 195useful you ask? Because this routine will allow you to encrypt an 196arbitrary number of bytes, without 8 byte padding. Each call to this 197routine will encrypt the input bytes to output and then update ivec 198and num. num contains 'how far' we are though ivec. If this does 199not make much sense, read more about CFB mode of DES. 200 201DES_ede3_cfb64_encrypt() and DES_ede2_cfb64_encrypt() is the same as 202DES_cfb64_encrypt() except that Triple-DES is used. 203 204DES_ofb_encrypt() encrypts using output feedback mode. This method 205takes an array of characters as input and outputs an array of 206characters. It does not require any padding to 8 character groups. 207Note: the I<ivec> variable is changed and the new changed value needs to 208be passed to the next call to this function. Since this function runs 209a complete DES ECB encryption per I<numbits>, this function is only 210suggested for use when sending a small number of characters. 211 212DES_ofb64_encrypt() is the same as DES_cfb64_encrypt() using Output 213Feed Back mode. 214 215DES_ede3_ofb64_encrypt() and DES_ede2_ofb64_encrypt() is the same as 216DES_ofb64_encrypt(), using Triple-DES. 217 218The following functions are included in the DES library for 219compatibility with the MIT Kerberos library. 220 221DES_cbc_cksum() produces an 8 byte checksum based on the input stream 222(via CBC encryption). The last 4 bytes of the checksum are returned 223and the complete 8 bytes are placed in I<output>. This function is 224used by Kerberos v4. Other applications should use 225L<EVP_DigestInit(3)> etc. instead. 226 227DES_quad_cksum() is a Kerberos v4 function. It returns a 4 byte 228checksum from the input bytes. The algorithm can be iterated over the 229input, depending on I<out_count>, 1, 2, 3 or 4 times. If I<output> is 230non-NULL, the 8 bytes generated by each pass are written into 231I<output>. 232 233The following are DES-based transformations: 234 235DES_fcrypt() is a fast version of the Unix crypt(3) function. This 236version takes only a small amount of space relative to other fast 237crypt() implementations. This is different to the normal crypt() in 238that the third parameter is the buffer that the return value is 239written into. It needs to be at least 14 bytes long. This function 240is thread safe, unlike the normal crypt(). 241 242DES_crypt() is a faster replacement for the normal system crypt(). 243This function calls DES_fcrypt() with a static array passed as the 244third parameter. This mostly emulates the normal non-thread-safe semantics 245of crypt(3). 246The B<salt> must be two ASCII characters. 247 248The values returned by DES_fcrypt() and DES_crypt() are terminated by NUL 249character. 250 251DES_enc_write() writes I<len> bytes to file descriptor I<fd> from 252buffer I<buf>. The data is encrypted via I<pcbc_encrypt> (default) 253using I<sched> for the key and I<iv> as a starting vector. The actual 254data send down I<fd> consists of 4 bytes (in network byte order) 255containing the length of the following encrypted data. The encrypted 256data then follows, padded with random data out to a multiple of 8 257bytes. 258 259=head1 BUGS 260 261DES_cbc_encrypt() does not modify B<ivec>; use DES_ncbc_encrypt() 262instead. 263 264DES_cfb_encrypt() and DES_ofb_encrypt() operates on input of 8 bits. 265What this means is that if you set numbits to 12, and length to 2, the 266first 12 bits will come from the 1st input byte and the low half of 267the second input byte. The second 12 bits will have the low 8 bits 268taken from the 3rd input byte and the top 4 bits taken from the 4th 269input byte. The same holds for output. This function has been 270implemented this way because most people will be using a multiple of 8 271and because once you get into pulling bytes input bytes apart things 272get ugly! 273 274DES_string_to_key() is available for backward compatibility with the 275MIT library. New applications should use a cryptographic hash function. 276The same applies for DES_string_to_2key(). 277 278=head1 NOTES 279 280The B<des> library was written to be source code compatible with 281the MIT Kerberos library. 282 283Applications should use the higher level functions 284L<EVP_EncryptInit(3)> etc. instead of calling these 285functions directly. 286 287Single-key DES is insecure due to its short key size. ECB mode is 288not suitable for most applications; see L<des_modes(7)>. 289 290=head1 RETURN VALUES 291 292DES_set_key(), DES_key_sched(), DES_set_key_checked() and DES_is_weak_key() 293return 0 on success or negative values on error. 294 295DES_cbc_cksum() and DES_quad_cksum() return 4-byte integer representing the 296last 4 bytes of the checksum of the input. 297 298DES_fcrypt() returns a pointer to the caller-provided buffer and DES_crypt() - 299to a static buffer on success; otherwise they return NULL. 300 301=head1 SEE ALSO 302 303L<des_modes(7)>, 304L<EVP_EncryptInit(3)> 305 306=head1 HISTORY 307 308The requirement that the B<salt> parameter to DES_crypt() and DES_fcrypt() 309be two ASCII characters was first enforced in 310OpenSSL 1.1.0. Previous versions tried to use the letter uppercase B<A> 311if both character were not present, and could crash when given non-ASCII 312on some platforms. 313 314=head1 COPYRIGHT 315 316Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved. 317 318Licensed under the OpenSSL license (the "License"). You may not use 319this file except in compliance with the License. You can obtain a copy 320in the file LICENSE in the source distribution or at 321L<https://www.openssl.org/source/license.html>. 322 323=cut 324