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 PRNG must be seeded 108prior to using this function (see L<RAND_bytes(3)>). If the PRNG 109could not generate a secure key, 0 is returned. 110 111Before a DES key can be used, it must be converted into the 112architecture dependent I<DES_key_schedule> via the 113DES_set_key_checked() or DES_set_key_unchecked() function. 114 115DES_set_key_checked() will check that the key passed is of odd parity 116and is not a weak or semi-weak key. If the parity is wrong, then -1 117is returned. If the key is a weak key, then -2 is returned. If an 118error is returned, the key schedule is not generated. 119 120DES_set_key() works like 121DES_set_key_checked() if the I<DES_check_key> flag is non-zero, 122otherwise like DES_set_key_unchecked(). These functions are available 123for compatibility; it is recommended to use a function that does not 124depend on a global variable. 125 126DES_set_odd_parity() sets the parity of the passed I<key> to odd. 127 128DES_is_weak_key() returns 1 if the passed key is a weak key, 0 if it 129is ok. 130 131The following routines mostly operate on an input and output stream of 132I<DES_cblock>s. 133 134DES_ecb_encrypt() is the basic DES encryption routine that encrypts or 135decrypts a single 8-byte I<DES_cblock> in I<electronic code book> 136(ECB) mode. It always transforms the input data, pointed to by 137I<input>, into the output data, pointed to by the I<output> argument. 138If the I<encrypt> argument is non-zero (DES_ENCRYPT), the I<input> 139(cleartext) is encrypted in to the I<output> (ciphertext) using the 140key_schedule specified by the I<schedule> argument, previously set via 141I<DES_set_key>. If I<encrypt> is zero (DES_DECRYPT), the I<input> (now 142ciphertext) is decrypted into the I<output> (now cleartext). Input 143and output may overlap. DES_ecb_encrypt() does not return a value. 144 145DES_ecb3_encrypt() encrypts/decrypts the I<input> block by using 146three-key Triple-DES encryption in ECB mode. This involves encrypting 147the input with I<ks1>, decrypting with the key schedule I<ks2>, and 148then encrypting with I<ks3>. This routine greatly reduces the chances 149of brute force breaking of DES and has the advantage of if I<ks1>, 150I<ks2> and I<ks3> are the same, it is equivalent to just encryption 151using ECB mode and I<ks1> as the key. 152 153The macro DES_ecb2_encrypt() is provided to perform two-key Triple-DES 154encryption by using I<ks1> for the final encryption. 155 156DES_ncbc_encrypt() encrypts/decrypts using the I<cipher-block-chaining> 157(CBC) mode of DES. If the I<encrypt> argument is non-zero, the 158routine cipher-block-chain encrypts the cleartext data pointed to by 159the I<input> argument into the ciphertext pointed to by the I<output> 160argument, using the key schedule provided by the I<schedule> argument, 161and initialization vector provided by the I<ivec> argument. If the 162I<length> argument is not an integral multiple of eight bytes, the 163last block is copied to a temporary area and zero filled. The output 164is always an integral multiple of eight bytes. 165 166DES_xcbc_encrypt() is RSA's DESX mode of DES. It uses I<inw> and 167I<outw> to 'whiten' the encryption. I<inw> and I<outw> are secret 168(unlike the iv) and are as such, part of the key. So the key is sort 169of 24 bytes. This is much better than CBC DES. 170 171DES_ede3_cbc_encrypt() implements outer triple CBC DES encryption with 172three keys. This means that each DES operation inside the CBC mode is 173C<C=E(ks3,D(ks2,E(ks1,M)))>. This mode is used by SSL. 174 175The DES_ede2_cbc_encrypt() macro implements two-key Triple-DES by 176reusing I<ks1> for the final encryption. C<C=E(ks1,D(ks2,E(ks1,M)))>. 177This form of Triple-DES is used by the RSAREF library. 178 179DES_pcbc_encrypt() encrypts/decrypts using the propagating cipher block 180chaining mode used by Kerberos v4. Its parameters are the same as 181DES_ncbc_encrypt(). 182 183DES_cfb_encrypt() encrypts/decrypts using cipher feedback mode. This 184method takes an array of characters as input and outputs an array of 185characters. It does not require any padding to 8 character groups. 186Note: the I<ivec> variable is changed and the new changed value needs to 187be passed to the next call to this function. Since this function runs 188a complete DES ECB encryption per I<numbits>, this function is only 189suggested for use when sending a small number of characters. 190 191DES_cfb64_encrypt() 192implements CFB mode of DES with 64-bit feedback. Why is this 193useful you ask? Because this routine will allow you to encrypt an 194arbitrary number of bytes, without 8 byte padding. Each call to this 195routine will encrypt the input bytes to output and then update ivec 196and num. num contains 'how far' we are though ivec. If this does 197not make much sense, read more about CFB mode of DES. 198 199DES_ede3_cfb64_encrypt() and DES_ede2_cfb64_encrypt() is the same as 200DES_cfb64_encrypt() except that Triple-DES is used. 201 202DES_ofb_encrypt() encrypts using output feedback mode. This method 203takes an array of characters as input and outputs an array of 204characters. It does not require any padding to 8 character groups. 205Note: the I<ivec> variable is changed and the new changed value needs to 206be passed to the next call to this function. Since this function runs 207a complete DES ECB encryption per I<numbits>, this function is only 208suggested for use when sending a small number of characters. 209 210DES_ofb64_encrypt() is the same as DES_cfb64_encrypt() using Output 211Feed Back mode. 212 213DES_ede3_ofb64_encrypt() and DES_ede2_ofb64_encrypt() is the same as 214DES_ofb64_encrypt(), using Triple-DES. 215 216The following functions are included in the DES library for 217compatibility with the MIT Kerberos library. 218 219DES_cbc_cksum() produces an 8 byte checksum based on the input stream 220(via CBC encryption). The last 4 bytes of the checksum are returned 221and the complete 8 bytes are placed in I<output>. This function is 222used by Kerberos v4. Other applications should use 223L<EVP_DigestInit(3)> etc. instead. 224 225DES_quad_cksum() is a Kerberos v4 function. It returns a 4 byte 226checksum from the input bytes. The algorithm can be iterated over the 227input, depending on I<out_count>, 1, 2, 3 or 4 times. If I<output> is 228non-NULL, the 8 bytes generated by each pass are written into 229I<output>. 230 231The following are DES-based transformations: 232 233DES_fcrypt() is a fast version of the Unix crypt(3) function. This 234version takes only a small amount of space relative to other fast 235crypt() implementations. This is different to the normal crypt() in 236that the third parameter is the buffer that the return value is 237written into. It needs to be at least 14 bytes long. This function 238is thread safe, unlike the normal crypt(). 239 240DES_crypt() is a faster replacement for the normal system crypt(). 241This function calls DES_fcrypt() with a static array passed as the 242third parameter. This mostly emulates the normal non-thread-safe semantics 243of crypt(3). 244The B<salt> must be two ASCII characters. 245 246The values returned by DES_fcrypt() and DES_crypt() are terminated by NUL 247character. 248 249DES_enc_write() writes I<len> bytes to file descriptor I<fd> from 250buffer I<buf>. The data is encrypted via I<pcbc_encrypt> (default) 251using I<sched> for the key and I<iv> as a starting vector. The actual 252data send down I<fd> consists of 4 bytes (in network byte order) 253containing the length of the following encrypted data. The encrypted 254data then follows, padded with random data out to a multiple of 8 255bytes. 256 257=head1 BUGS 258 259DES_cbc_encrypt() does not modify B<ivec>; use DES_ncbc_encrypt() 260instead. 261 262DES_cfb_encrypt() and DES_ofb_encrypt() operates on input of 8 bits. 263What this means is that if you set numbits to 12, and length to 2, the 264first 12 bits will come from the 1st input byte and the low half of 265the second input byte. The second 12 bits will have the low 8 bits 266taken from the 3rd input byte and the top 4 bits taken from the 4th 267input byte. The same holds for output. This function has been 268implemented this way because most people will be using a multiple of 8 269and because once you get into pulling bytes input bytes apart things 270get ugly! 271 272DES_string_to_key() is available for backward compatibility with the 273MIT library. New applications should use a cryptographic hash function. 274The same applies for DES_string_to_2key(). 275 276=head1 NOTES 277 278The B<des> library was written to be source code compatible with 279the MIT Kerberos library. 280 281Applications should use the higher level functions 282L<EVP_EncryptInit(3)> etc. instead of calling these 283functions directly. 284 285Single-key DES is insecure due to its short key size. ECB mode is 286not suitable for most applications; see L<des_modes(7)>. 287 288=head1 RETURN VALUES 289 290DES_set_key(), DES_key_sched(), DES_set_key_checked() and DES_is_weak_key() 291return 0 on success or negative values on error. 292 293DES_cbc_cksum() and DES_quad_cksum() return 4-byte integer representing the 294last 4 bytes of the checksum of the input. 295 296DES_fcrypt() returns a pointer to the caller-provided buffer and DES_crypt() - 297to a static buffer on success; otherwise they return NULL. 298 299=head1 SEE ALSO 300 301L<des_modes(7)>, 302L<EVP_EncryptInit(3)> 303 304=head1 HISTORY 305 306The requirement that the B<salt> parameter to DES_crypt() and DES_fcrypt() 307be two ASCII characters was first enforced in 308OpenSSL 1.1.0. Previous versions tried to use the letter uppercase B<A> 309if both character were not present, and could crash when given non-ASCII 310on some platforms. 311 312=head1 COPYRIGHT 313 314Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved. 315 316Licensed under the OpenSSL license (the "License"). You may not use 317this file except in compliance with the License. You can obtain a copy 318in the file LICENSE in the source distribution or at 319L<https://www.openssl.org/source/license.html>. 320 321=cut 322