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Diffstat (limited to 'src/lib/libcrypto/man/BN_generate_prime.3')
| -rw-r--r-- | src/lib/libcrypto/man/BN_generate_prime.3 | 289 |
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diff --git a/src/lib/libcrypto/man/BN_generate_prime.3 b/src/lib/libcrypto/man/BN_generate_prime.3 new file mode 100644 index 0000000000..e269571914 --- /dev/null +++ b/src/lib/libcrypto/man/BN_generate_prime.3 | |||
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| 1 | .Dd $Mdocdate: February 23 2015 $ | ||
| 2 | .Dt BN_GENERATE_PRIME 3 | ||
| 3 | .Os | ||
| 4 | .Sh NAME | ||
| 5 | .Nm BN_generate_prime_ex , | ||
| 6 | .Nm BN_is_prime_ex , | ||
| 7 | .Nm BN_is_prime_fasttest_ex , | ||
| 8 | .Nm BN_GENCB_call , | ||
| 9 | .Nm BN_GENCB_set_old , | ||
| 10 | .Nm BN_GENCB_set , | ||
| 11 | .Nm BN_generate_prime , | ||
| 12 | .Nm BN_is_prime , | ||
| 13 | .Nm BN_is_prime_fasttest | ||
| 14 | .Nd generate primes and test for primality | ||
| 15 | .Sh SYNOPSIS | ||
| 16 | .In openssl/bn.h | ||
| 17 | .Ft int | ||
| 18 | .Fo BN_generate_prime_ex | ||
| 19 | .Fa "BIGNUM *ret" | ||
| 20 | .Fa "int bits" | ||
| 21 | .Fa "int safe" | ||
| 22 | .Fa "const BIGNUM *add" | ||
| 23 | .Fa "const BIGNUM *rem" | ||
| 24 | .Fa "BN_GENCB *cb" | ||
| 25 | .Fc | ||
| 26 | .Ft int | ||
| 27 | .Fo BN_is_prime_ex | ||
| 28 | .Fa "const BIGNUM *p" | ||
| 29 | .Fa "int nchecks" | ||
| 30 | .Fa "BN_CTX *ctx" | ||
| 31 | .Fa "BN_GENCB *cb" | ||
| 32 | .Fc | ||
| 33 | .Ft int | ||
| 34 | .Fo BN_is_prime_fasttest_ex | ||
| 35 | .Fa "const BIGNUM *p" | ||
| 36 | .Fa "int nchecks" | ||
| 37 | .Fa "BN_CTX *ctx" | ||
| 38 | .Fa "int do_trial_division" | ||
| 39 | .Fa "BN_GENCB *cb" | ||
| 40 | .Fc | ||
| 41 | .Ft int | ||
| 42 | .Fo BN_GENCB_call | ||
| 43 | .Fa "BN_GENCB *cb" | ||
| 44 | .Fa "int a" | ||
| 45 | .Fa "int b" | ||
| 46 | .Fc | ||
| 47 | .Fd #define BN_GENCB_set_old(gencb, callback, cb_arg) ... | ||
| 48 | .Fd #define BN_GENCB_set(gencb, callback, cb_arg) ... | ||
| 49 | .Pp | ||
| 50 | Deprecated: | ||
| 51 | .Pp | ||
| 52 | .Ft BIGNUM * | ||
| 53 | .Fo BN_generate_prime | ||
| 54 | .Fa "BIGNUM *ret" | ||
| 55 | .Fa "int num" | ||
| 56 | .Fa "int safe" | ||
| 57 | .Fa "BIGNUM *add" | ||
| 58 | .Fa "BIGNUM *rem" | ||
| 59 | .Fa "void (*callback)(int, int, void *)" | ||
| 60 | .Fa "void *cb_arg" | ||
| 61 | .Fc | ||
| 62 | .Ft int | ||
| 63 | .Fo BN_is_prime | ||
| 64 | .Fa "const BIGNUM *a" | ||
| 65 | .Fa "int checks" | ||
| 66 | .Fa "void (*callback)(int, int, void *)" | ||
| 67 | .Fa "BN_CTX *ctx" | ||
| 68 | .Fa "void *cb_arg" | ||
| 69 | .Fc | ||
| 70 | .Ft int | ||
| 71 | .Fo BN_is_prime_fasttest | ||
| 72 | .Fa "const BIGNUM *a" | ||
| 73 | .Fa "int checks" | ||
| 74 | .Fa "void (*callback)(int, int, void *)" | ||
| 75 | .Fa "BN_CTX *ctx" | ||
| 76 | .Fa "void *cb_arg" | ||
| 77 | .Fa "int do_trial_division" | ||
| 78 | .Fc | ||
| 79 | .Sh DESCRIPTION | ||
| 80 | .Fn BN_generate_prime_ex | ||
| 81 | generates a pseudo-random prime number of bit length | ||
| 82 | .Fa bits . | ||
| 83 | If | ||
| 84 | .Fa ret | ||
| 85 | is not | ||
| 86 | .Dv NULL , | ||
| 87 | it will be used to store the number. | ||
| 88 | .Pp | ||
| 89 | If | ||
| 90 | .Fa cb | ||
| 91 | is not | ||
| 92 | .Dv NULL , | ||
| 93 | it is used as follows: | ||
| 94 | .Bl -bullet | ||
| 95 | .It | ||
| 96 | .Fn BN_GENCB_call cb 0 i | ||
| 97 | is called after generating the i-th potential prime number. | ||
| 98 | .It | ||
| 99 | While the number is being tested for primality, | ||
| 100 | .Fn BN_GENCB_call cb 1 j | ||
| 101 | is called as described below. | ||
| 102 | .It | ||
| 103 | When a prime has been found, | ||
| 104 | .Fn BN_GENCB_call cb 2 i | ||
| 105 | is called. | ||
| 106 | .El | ||
| 107 | .Pp | ||
| 108 | The prime may have to fulfill additional requirements for use in | ||
| 109 | Diffie-Hellman key exchange: | ||
| 110 | .Pp | ||
| 111 | If | ||
| 112 | .Fa add | ||
| 113 | is not | ||
| 114 | .Dv NULL , | ||
| 115 | the prime will fulfill the condition p % | ||
| 116 | .Fa add | ||
| 117 | == | ||
| 118 | .Fa rem | ||
| 119 | (p % | ||
| 120 | .Fa add | ||
| 121 | == 1 if | ||
| 122 | .Fa rem | ||
| 123 | == | ||
| 124 | .Dv NULL ) | ||
| 125 | in order to suit a given generator. | ||
| 126 | .Pp | ||
| 127 | If | ||
| 128 | .Fa safe | ||
| 129 | is true, it will be a safe prime (i.e. a prime p so that (p-1)/2 | ||
| 130 | is also prime). | ||
| 131 | .Pp | ||
| 132 | The prime number generation has a negligible error probability. | ||
| 133 | .Pp | ||
| 134 | .Fn BN_is_prime_ex | ||
| 135 | and | ||
| 136 | .Fn BN_is_prime_fasttest_ex | ||
| 137 | test if the number | ||
| 138 | .Fa p | ||
| 139 | is prime. | ||
| 140 | The following tests are performed until one of them shows that | ||
| 141 | .Fa p | ||
| 142 | is composite; if | ||
| 143 | .Fa p | ||
| 144 | passes all these tests, it is considered prime. | ||
| 145 | .Pp | ||
| 146 | .Fn BN_is_prime_fasttest_ex , | ||
| 147 | when called with | ||
| 148 | .Fa do_trial_division | ||
| 149 | == 1, first attempts trial division by a number of small primes; | ||
| 150 | if no divisors are found by this test and | ||
| 151 | .Fa cb | ||
| 152 | is not | ||
| 153 | .Dv NULL , | ||
| 154 | .Sy BN_GENCB_call(cb, 1, -1) | ||
| 155 | is called. | ||
| 156 | If | ||
| 157 | .Fa do_trial_division | ||
| 158 | == 0, this test is skipped. | ||
| 159 | .Pp | ||
| 160 | Both | ||
| 161 | .Fn BN_is_prime_ex | ||
| 162 | and | ||
| 163 | .Fn BN_is_prime_fasttest_ex | ||
| 164 | perform a Miller-Rabin probabilistic primality test with | ||
| 165 | .Fa nchecks | ||
| 166 | iterations. | ||
| 167 | If | ||
| 168 | .Fa nchecks | ||
| 169 | == | ||
| 170 | .Dv BN_prime_checks , | ||
| 171 | a number of iterations is used that yields a false positive rate of at | ||
| 172 | most 2^-80 for random input. | ||
| 173 | .Pp | ||
| 174 | If | ||
| 175 | .Fa cb | ||
| 176 | is not | ||
| 177 | .Dv NULL , | ||
| 178 | .Fa BN_GENCB_call cb 1 j | ||
| 179 | is called after the j-th iteration (j = 0, 1, ...). | ||
| 180 | .Fa ctx | ||
| 181 | is a pre-allocated | ||
| 182 | .Vt BN_CTX | ||
| 183 | (to save the overhead of allocating and freeing the structure in a | ||
| 184 | loop), or | ||
| 185 | .Dv NULL . | ||
| 186 | .Pp | ||
| 187 | .Fn BN_GENCB_call | ||
| 188 | calls the callback function held in the | ||
| 189 | .Vt BN_GENCB | ||
| 190 | structure and passes the ints | ||
| 191 | .Fa a | ||
| 192 | and | ||
| 193 | .Fa b | ||
| 194 | as arguments. | ||
| 195 | There are two types of | ||
| 196 | .Vt BN_GENCB | ||
| 197 | structures that are supported: "new" style and "old" style. | ||
| 198 | New programs should prefer the "new" style, whilst the "old" style is | ||
| 199 | provided for backwards compatibility purposes. | ||
| 200 | .Pp | ||
| 201 | For "new" style callbacks a | ||
| 202 | .Vt BN_GENCB | ||
| 203 | structure should be initialised with a call to | ||
| 204 | .Fn BN_GENCB_set , | ||
| 205 | where | ||
| 206 | .Fa gencb | ||
| 207 | is a | ||
| 208 | .Vt BN_GENCB * , | ||
| 209 | .Fa callback | ||
| 210 | is of type | ||
| 211 | .Vt int (*callback)(int, int, BN_GENCB *) | ||
| 212 | and | ||
| 213 | .Fa cb_arg | ||
| 214 | is a | ||
| 215 | .Vt void * . | ||
| 216 | "Old" style callbacks are the same except they are initialised with a | ||
| 217 | call to | ||
| 218 | .Fn BN_GENCB_set_old | ||
| 219 | and | ||
| 220 | .Fa callback | ||
| 221 | is of type | ||
| 222 | .Vt void (*callback)(int, int, void *) . | ||
| 223 | .Pp | ||
| 224 | A callback is invoked through a call to | ||
| 225 | .Fn BN_GENCB_call . | ||
| 226 | This will check the type of the callback and will invoke | ||
| 227 | .Fn callback a b gencb | ||
| 228 | for new style callbacks or | ||
| 229 | .Fn callback a b cb_arg | ||
| 230 | for old style. | ||
| 231 | .Pp | ||
| 232 | .Fn BN_generate_prime | ||
| 233 | (deprecated) works in the same way as | ||
| 234 | .Fn BN_generate_prime_ex | ||
| 235 | but expects an old style callback function directly in the | ||
| 236 | .Fa callback | ||
| 237 | parameter, and an argument to pass to it in the | ||
| 238 | .Fa cb_arg . | ||
| 239 | Similarly | ||
| 240 | .Fn BN_is_prime | ||
| 241 | and | ||
| 242 | .Fn BN_is_prime_fasttest | ||
| 243 | are deprecated and can be compared to | ||
| 244 | .Fn BN_is_prime_ex | ||
| 245 | and | ||
| 246 | .Fn BN_is_prime_fasttest_ex | ||
| 247 | respectively. | ||
| 248 | .Sh RETURN VALUES | ||
| 249 | .Fn BN_generate_prime_ex | ||
| 250 | returns 1 on success or 0 on error. | ||
| 251 | .Pp | ||
| 252 | .Fn BN_is_prime_ex , | ||
| 253 | .Fn BN_is_prime_fasttest_ex , | ||
| 254 | .Fn BN_is_prime , | ||
| 255 | and | ||
| 256 | .Fn BN_is_prime_fasttest | ||
| 257 | return 0 if the number is composite, 1 if it is prime with an error | ||
| 258 | probability of less than | ||
| 259 | .Pf 0.25^ Fa nchecks , | ||
| 260 | and -1 on error. | ||
| 261 | .Pp | ||
| 262 | .Fn BN_generate_prime | ||
| 263 | returns the prime number on success, | ||
| 264 | .Dv NULL | ||
| 265 | otherwise. | ||
| 266 | .Pp | ||
| 267 | Callback functions should return 1 on success or 0 on error. | ||
| 268 | .Pp | ||
| 269 | The error codes can be obtained by | ||
| 270 | .Xr ERR_get_error 3 . | ||
| 271 | .Sh SEE ALSO | ||
| 272 | .Xr bn 3 , | ||
| 273 | .Xr ERR_get_error 3 , | ||
| 274 | .Xr rand 3 | ||
| 275 | .Sh HISTORY | ||
| 276 | The | ||
| 277 | .Fa cb_arg | ||
| 278 | arguments to | ||
| 279 | .Fn BN_generate_prime | ||
| 280 | and to | ||
| 281 | .Fn BN_is_prime | ||
| 282 | were added in SSLeay 0.9.0. | ||
| 283 | The | ||
| 284 | .Fa ret | ||
| 285 | argument to | ||
| 286 | .Fn BN_generate_prime | ||
| 287 | was added in SSLeay 0.9.1. | ||
| 288 | .Fn BN_is_prime_fasttest | ||
| 289 | was added in OpenSSL 0.9.5. | ||
