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| author | schwarze <> | 2016-11-02 11:57:56 +0000 |
|---|---|---|
| committer | schwarze <> | 2016-11-02 11:57:56 +0000 |
| commit | cc11de9530a463cf1046e63cc0a8b635aa93cdae (patch) | |
| tree | 62d26e7f75bb451eba292aad57737306b2f28280 /src/lib/libcrypto/man/EC_GROUP_copy.3 | |
| parent | 849e449a83384719b38a7cfdafafc48800004525 (diff) | |
| download | openbsd-cc11de9530a463cf1046e63cc0a8b635aa93cdae.tar.gz openbsd-cc11de9530a463cf1046e63cc0a8b635aa93cdae.tar.bz2 openbsd-cc11de9530a463cf1046e63cc0a8b635aa93cdae.zip | |
convert DSA and EC manuals from pod to mdoc
Diffstat (limited to 'src/lib/libcrypto/man/EC_GROUP_copy.3')
| -rw-r--r-- | src/lib/libcrypto/man/EC_GROUP_copy.3 | 434 |
1 files changed, 434 insertions, 0 deletions
diff --git a/src/lib/libcrypto/man/EC_GROUP_copy.3 b/src/lib/libcrypto/man/EC_GROUP_copy.3 new file mode 100644 index 0000000000..61c094700a --- /dev/null +++ b/src/lib/libcrypto/man/EC_GROUP_copy.3 | |||
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| 1 | .Dd $Mdocdate: November 2 2016 $ | ||
| 2 | .Dt EC_GROUP_COPY 3 | ||
| 3 | .Os | ||
| 4 | .Sh NAME | ||
| 5 | .Nm EC_GROUP_copy , | ||
| 6 | .Nm EC_GROUP_dup , | ||
| 7 | .Nm EC_GROUP_method_of , | ||
| 8 | .Nm EC_GROUP_set_generator , | ||
| 9 | .Nm EC_GROUP_get0_generator , | ||
| 10 | .Nm EC_GROUP_get_order , | ||
| 11 | .Nm EC_GROUP_get_cofactor , | ||
| 12 | .Nm EC_GROUP_set_curve_name , | ||
| 13 | .Nm EC_GROUP_get_curve_name , | ||
| 14 | .Nm EC_GROUP_set_asn1_flag , | ||
| 15 | .Nm EC_GROUP_get_asn1_flag , | ||
| 16 | .Nm EC_GROUP_set_point_conversion_form , | ||
| 17 | .Nm EC_GROUP_get_point_conversion_form , | ||
| 18 | .Nm EC_GROUP_get0_seed , | ||
| 19 | .Nm EC_GROUP_get_seed_len , | ||
| 20 | .Nm EC_GROUP_set_seed , | ||
| 21 | .Nm EC_GROUP_get_degree , | ||
| 22 | .Nm EC_GROUP_check , | ||
| 23 | .Nm EC_GROUP_check_discriminant , | ||
| 24 | .Nm EC_GROUP_cmp , | ||
| 25 | .Nm EC_GROUP_get_basis_type , | ||
| 26 | .Nm EC_GROUP_get_trinomial_basis , | ||
| 27 | .Nm EC_GROUP_get_pentanomial_basis | ||
| 28 | .Nd manipulate EC_GROUP objects | ||
| 29 | .Sh SYNOPSIS | ||
| 30 | .In openssl/ec.h | ||
| 31 | .In openssl/bn.h | ||
| 32 | .Ft int | ||
| 33 | .Fo EC_GROUP_copy | ||
| 34 | .Fa "EC_GROUP *dst" | ||
| 35 | .Fa "const EC_GROUP *src" | ||
| 36 | .Fc | ||
| 37 | .Ft EC_GROUP * | ||
| 38 | .Fo EC_GROUP_dup | ||
| 39 | .Fa "const EC_GROUP *src" | ||
| 40 | .Fc | ||
| 41 | .Ft const EC_METHOD * | ||
| 42 | .Fo EC_GROUP_method_of | ||
| 43 | .Fa "const EC_GROUP *group" | ||
| 44 | .Fc | ||
| 45 | .Ft int | ||
| 46 | .Fo EC_GROUP_set_generator | ||
| 47 | .Fa "EC_GROUP *group" | ||
| 48 | .Fa "const EC_POINT *generator" | ||
| 49 | .Fa "const BIGNUM *order" | ||
| 50 | .Fa "const BIGNUM *cofactor" | ||
| 51 | .Fc | ||
| 52 | .Ft const EC_POINT * | ||
| 53 | .Fo EC_GROUP_get0_generator | ||
| 54 | .Fa "const EC_GROUP *group" | ||
| 55 | .Fc | ||
| 56 | .Ft int | ||
| 57 | .Fo EC_GROUP_get_order | ||
| 58 | .Fa "const EC_GROUP *group" | ||
| 59 | .Fa "BIGNUM *order" | ||
| 60 | .Fa "BN_CTX *ctx" | ||
| 61 | .Fc | ||
| 62 | .Ft int | ||
| 63 | .Fo EC_GROUP_get_cofactor | ||
| 64 | .Fa "const EC_GROUP *group" | ||
| 65 | .Fa "BIGNUM *cofactor" | ||
| 66 | .Fa "BN_CTX *ctx" | ||
| 67 | .Fc | ||
| 68 | .Ft void | ||
| 69 | .Fo EC_GROUP_set_curve_name | ||
| 70 | .Fa "EC_GROUP *group" | ||
| 71 | .Fa "int nid" | ||
| 72 | .Fc | ||
| 73 | .Ft int | ||
| 74 | .Fo EC_GROUP_get_curve_name | ||
| 75 | .Fa "const EC_GROUP *group" | ||
| 76 | .Fc | ||
| 77 | .Ft void | ||
| 78 | .Fo EC_GROUP_set_asn1_flag | ||
| 79 | .Fa "EC_GROUP *group" | ||
| 80 | .Fa "int flag" | ||
| 81 | .Fc | ||
| 82 | .Ft int | ||
| 83 | .Fo EC_GROUP_get_asn1_flag | ||
| 84 | .Fa "const EC_GROUP *group" | ||
| 85 | .Fc | ||
| 86 | .Ft void | ||
| 87 | .Fo EC_GROUP_set_point_conversion_form | ||
| 88 | .Fa "EC_GROUP *group" | ||
| 89 | .Fa "point_conversion_form_t form" | ||
| 90 | .Fc | ||
| 91 | .Ft point_conversion_form_t | ||
| 92 | .Fo EC_GROUP_get_point_conversion_form | ||
| 93 | .Fa "const EC_GROUP *" | ||
| 94 | .Fc | ||
| 95 | .Ft unsigned char * | ||
| 96 | .Fo EC_GROUP_get0_seed | ||
| 97 | .Fa "const EC_GROUP *x" | ||
| 98 | .Fc | ||
| 99 | .Ft size_t | ||
| 100 | .Fo EC_GROUP_get_seed_len | ||
| 101 | .Fa "const EC_GROUP *" | ||
| 102 | .Fc | ||
| 103 | .Ft size_t | ||
| 104 | .Fo EC_GROUP_set_seed | ||
| 105 | .Fa "EC_GROUP *" | ||
| 106 | .Fa "const unsigned char *" | ||
| 107 | .Fa "size_t len" | ||
| 108 | .Fc | ||
| 109 | .Ft int | ||
| 110 | .Fo EC_GROUP_get_degree | ||
| 111 | .Fa "const EC_GROUP *group" | ||
| 112 | .Fc | ||
| 113 | .Ft int | ||
| 114 | .Fo EC_GROUP_check | ||
| 115 | .Fa "const EC_GROUP *group" | ||
| 116 | .Fa "BN_CTX *ctx" | ||
| 117 | .Fc | ||
| 118 | .Ft int | ||
| 119 | .Fo EC_GROUP_check_discriminant | ||
| 120 | .Fa "const EC_GROUP *group" | ||
| 121 | .Fa "BN_CTX *ctx" | ||
| 122 | .Fc | ||
| 123 | .Ft int | ||
| 124 | .Fo EC_GROUP_cmp | ||
| 125 | .Fa "const EC_GROUP *a" | ||
| 126 | .Fa "const EC_GROUP *b" | ||
| 127 | .Fa "BN_CTX *ctx" | ||
| 128 | .Fc | ||
| 129 | .Ft int | ||
| 130 | .Fo EC_GROUP_get_basis_type | ||
| 131 | .Fa "const EC_GROUP *" | ||
| 132 | .Fc | ||
| 133 | .Ft int | ||
| 134 | .Fo EC_GROUP_get_trinomial_basis | ||
| 135 | .Fa "const EC_GROUP *" | ||
| 136 | .Fa "unsigned int *k" | ||
| 137 | .Fc | ||
| 138 | .Ft int | ||
| 139 | .Fo EC_GROUP_get_pentanomial_basis | ||
| 140 | .Fa "const EC_GROUP *" | ||
| 141 | .Fa "unsigned int *k1" | ||
| 142 | .Fa "unsigned int *k2" | ||
| 143 | .Fa "unsigned int *k3" | ||
| 144 | .Fc | ||
| 145 | .Sh DESCRIPTION | ||
| 146 | .Fn EC_GROUP_copy | ||
| 147 | copies the curve | ||
| 148 | .Fa src | ||
| 149 | into | ||
| 150 | .Fa dst . | ||
| 151 | Both | ||
| 152 | .Fa src | ||
| 153 | and | ||
| 154 | .Fa dst | ||
| 155 | must use the same | ||
| 156 | .Vt EC_METHOD . | ||
| 157 | .Pp | ||
| 158 | .Fn EC_GROUP_dup | ||
| 159 | creates a new | ||
| 160 | .Vt EC_GROUP | ||
| 161 | object and copies the content from | ||
| 162 | .Fa src | ||
| 163 | to the newly created | ||
| 164 | .Vt EC_GROUP | ||
| 165 | object. | ||
| 166 | .Pp | ||
| 167 | .Fn EC_GROUP_method_of | ||
| 168 | obtains the | ||
| 169 | .Vt EC_METHOD | ||
| 170 | of | ||
| 171 | .Fa group . | ||
| 172 | .Pp | ||
| 173 | .Fn EC_GROUP_set_generator | ||
| 174 | sets curve paramaters that must be agreed by all participants using | ||
| 175 | the curve. | ||
| 176 | These paramaters include the | ||
| 177 | .Fa generator , | ||
| 178 | the | ||
| 179 | .Fa order | ||
| 180 | and the | ||
| 181 | .Fa cofactor . | ||
| 182 | The | ||
| 183 | .Fa generator | ||
| 184 | is a well defined point on the curve chosen for cryptographic | ||
| 185 | operations. | ||
| 186 | Integers used for point multiplications will be between 0 and | ||
| 187 | .Fa order No - 1 . | ||
| 188 | The | ||
| 189 | .Fa order | ||
| 190 | multipied by the | ||
| 191 | .Fa cofactor | ||
| 192 | gives the number of points on the curve. | ||
| 193 | .Pp | ||
| 194 | .Fn EC_GROUP_get0_generator | ||
| 195 | returns the generator for the identified | ||
| 196 | .Fa group . | ||
| 197 | .Pp | ||
| 198 | The functions | ||
| 199 | .Fn EC_GROUP_get_order | ||
| 200 | and | ||
| 201 | .Fn EC_GROUP_get_cofactor | ||
| 202 | populate the provided | ||
| 203 | .Fa order | ||
| 204 | and | ||
| 205 | .Fa cofactor | ||
| 206 | parameters with the respective order and cofactors for the | ||
| 207 | .Fa group . | ||
| 208 | .Pp | ||
| 209 | The functions | ||
| 210 | .Fn EC_GROUP_set_curve_name | ||
| 211 | and | ||
| 212 | .Fn EC_GROUP_get_curve_name | ||
| 213 | set and get the NID for the curve, respectively (see | ||
| 214 | .Xr EC_GROUP_new 3 ) . | ||
| 215 | If a curve does not have a NID associated with it, then | ||
| 216 | .Fn EC_GROUP_get_curve_name | ||
| 217 | will return 0. | ||
| 218 | .Pp | ||
| 219 | The asn1_flag value on a curve is used to determine whether there is a | ||
| 220 | specific ASN1 OID to describe the curve or not. | ||
| 221 | If the asn1_flag is 1 then this is a named curve with an associated ASN1 OID. | ||
| 222 | If not then asn1_flag is 0. | ||
| 223 | The functions | ||
| 224 | .Fn EC_GROUP_get_asn1_flag | ||
| 225 | and | ||
| 226 | .Fn EC_GROUP_set_asn1_flag | ||
| 227 | get and set the status of the asn1_flag for the curve. | ||
| 228 | If set, then the curve_name must also be set. | ||
| 229 | .Pp | ||
| 230 | The point_conversion_form for a curve controls how | ||
| 231 | .Vt EC_POINT | ||
| 232 | data is encoded as ASN1 as defined in X9.62 (ECDSA). | ||
| 233 | .Vt point_conversion_form_t | ||
| 234 | is an enum defined as follows: | ||
| 235 | .Bd -literal | ||
| 236 | typedef enum { | ||
| 237 | /** the point is encoded as z||x, where the octet z specifies | ||
| 238 | * which solution of the quadratic equation y is */ | ||
| 239 | POINT_CONVERSION_COMPRESSED = 2, | ||
| 240 | /** the point is encoded as z||x||y, where z is the octet 0x02 */ | ||
| 241 | POINT_CONVERSION_UNCOMPRESSED = 4, | ||
| 242 | /** the point is encoded as z||x||y, where the octet z specifies | ||
| 243 | * which solution of the quadratic equation y is */ | ||
| 244 | POINT_CONVERSION_HYBRID = 6 | ||
| 245 | } point_conversion_form_t; | ||
| 246 | .Ed | ||
| 247 | .Pp | ||
| 248 | For | ||
| 249 | .Dv POINT_CONVERSION_UNCOMPRESSED | ||
| 250 | the point is encoded as an octet signifying the UNCOMPRESSED form | ||
| 251 | has been used followed by the octets for x, followed by the octets | ||
| 252 | for y. | ||
| 253 | .Pp | ||
| 254 | For any given x co-ordinate for a point on a curve it is possible to | ||
| 255 | derive two possible y values. | ||
| 256 | For | ||
| 257 | .Dv POINT_CONVERSION_COMPRESSED | ||
| 258 | the point is encoded as an octet signifying that the COMPRESSED | ||
| 259 | form has been used AND which of the two possible solutions for y | ||
| 260 | has been used, followed by the octets for x. | ||
| 261 | .Pp | ||
| 262 | For | ||
| 263 | .Dv POINT_CONVERSION_HYBRID | ||
| 264 | the point is encoded as an octet signifying the HYBRID form has | ||
| 265 | been used AND which of the two possible solutions for y has been | ||
| 266 | used, followed by the octets for x, followed by the octets for y. | ||
| 267 | .Pp | ||
| 268 | The functions | ||
| 269 | .Fn EC_GROUP_set_point_conversion_form | ||
| 270 | and | ||
| 271 | .Fn EC_GROUP_get_point_conversion_form | ||
| 272 | set and get the point_conversion_form for the curve, respectively. | ||
| 273 | .Pp | ||
| 274 | ANSI X9.62 (ECDSA standard) defines a method of generating the curve | ||
| 275 | parameter b from a random number. | ||
| 276 | This provides advantages in that a parameter obtained in this way is | ||
| 277 | highly unlikely to be susceptible to special purpose attacks, or have | ||
| 278 | any trapdoors in it. | ||
| 279 | If the seed is present for a curve then the b parameter was generated in | ||
| 280 | a verifiable fashion using that seed. | ||
| 281 | The OpenSSL EC library does not use this seed value but does enable you | ||
| 282 | to inspect it using | ||
| 283 | .Fn EC_GROUP_get0_seed . | ||
| 284 | This returns a pointer to a memory block containing the seed that was | ||
| 285 | used. | ||
| 286 | The length of the memory block can be obtained using | ||
| 287 | .Fn EC_GROUP_get_seed_len . | ||
| 288 | A number of the builtin curves within the library provide seed values | ||
| 289 | that can be obtained. | ||
| 290 | It is also possible to set a custom seed using | ||
| 291 | .Fn EC_GROUP_set_seed | ||
| 292 | and passing a pointer to a memory block, along with the length of | ||
| 293 | the seed. | ||
| 294 | Again, the EC library will not use this seed value, although it will be | ||
| 295 | preserved in any ASN1 based communications. | ||
| 296 | .Pp | ||
| 297 | .Fn EC_GROUP_get_degree | ||
| 298 | gets the degree of the field. | ||
| 299 | For Fp fields this will be the number of bits in p. | ||
| 300 | For F2^m fields this will be the value m. | ||
| 301 | .Pp | ||
| 302 | The function | ||
| 303 | .Fn EC_GROUP_check_discriminant | ||
| 304 | calculates the discriminant for the curve and verifies that it is | ||
| 305 | valid. | ||
| 306 | For a curve defined over Fp the discriminant is given by the formula | ||
| 307 | 4*a^3 + 27*b^2 whilst for F2^m curves the discriminant is simply b. | ||
| 308 | In either case for the curve to be valid the discriminant must be | ||
| 309 | non-zero. | ||
| 310 | .Pp | ||
| 311 | The function | ||
| 312 | .Fn EC_GROUP_check | ||
| 313 | performs a number of checks on a curve to verify that it is valid. | ||
| 314 | Checks performed include verifying that the discriminant is non zero; | ||
| 315 | that a generator has been defined; that the generator is on the curve | ||
| 316 | and has the correct order. | ||
| 317 | .Pp | ||
| 318 | .Fn EC_GROUP_cmp | ||
| 319 | compares | ||
| 320 | .Fa a | ||
| 321 | and | ||
| 322 | .Fa b | ||
| 323 | to determine whether they represent the same curve or not. | ||
| 324 | .Pp | ||
| 325 | The functions | ||
| 326 | .Fn EC_GROUP_get_basis_type , | ||
| 327 | .Fn EC_GROUP_get_trinomial_basis , | ||
| 328 | and | ||
| 329 | .Fn EC_GROUP_get_pentanomial_basis | ||
| 330 | should only be called for curves defined over an F2^m field. | ||
| 331 | Addition and multiplication operations within an F2^m field are | ||
| 332 | performed using an irreducible polynomial function f(x). | ||
| 333 | This function is either a trinomial of the form: | ||
| 334 | .Pp | ||
| 335 | .Dl f(x) = x^m + x^k + 1 with m > k >= 1 | ||
| 336 | .Pp | ||
| 337 | or a pentanomial of the form: | ||
| 338 | .Pp | ||
| 339 | .Dl f(x) = x^m + x^k3 + x^k2 + x^k1 + 1 with m > k3 > k2 > k1 >= 1 | ||
| 340 | .Pp | ||
| 341 | The function | ||
| 342 | .Fn EC_GROUP_get_basis_type | ||
| 343 | returns a NID identifying whether a trinomial or pentanomial is in | ||
| 344 | use for the field. | ||
| 345 | The function | ||
| 346 | .Fn EC_GROUP_get_trinomial_basis | ||
| 347 | must only be called where f(x) is of the trinomial form, and returns | ||
| 348 | the value of | ||
| 349 | .Fa k . | ||
| 350 | Similarly, the function | ||
| 351 | .Fn EC_GROUP_get_pentanomial_basis | ||
| 352 | must only be called where f(x) is of the pentanomial form, and | ||
| 353 | returns the values of | ||
| 354 | .Fa k1 , | ||
| 355 | .Fa k2 , | ||
| 356 | and | ||
| 357 | .Fa k3 . | ||
| 358 | .Sh RETURN VALUES | ||
| 359 | The following functions return 1 on success or 0 on error: | ||
| 360 | .Fn EC_GROUP_copy , | ||
| 361 | .Fn EC_GROUP_set_generator , | ||
| 362 | .Fn EC_GROUP_check , | ||
| 363 | .Fn EC_GROUP_check_discriminant , | ||
| 364 | .Fn EC_GROUP_get_trinomial_basis , | ||
| 365 | and | ||
| 366 | .Fn EC_GROUP_get_pentanomial_basis . | ||
| 367 | .Pp | ||
| 368 | .Fn EC_GROUP_dup | ||
| 369 | returns a pointer to the duplicated curve or | ||
| 370 | .Dv NULL | ||
| 371 | on error. | ||
| 372 | .Pp | ||
| 373 | .Fn EC_GROUP_method_of | ||
| 374 | returns the | ||
| 375 | .Vt EC_METHOD | ||
| 376 | implementation in use for the given curve or | ||
| 377 | .Dv NULL | ||
| 378 | on error. | ||
| 379 | .Pp | ||
| 380 | .Fn EC_GROUP_get0_generator | ||
| 381 | returns the generator for the given curve or | ||
| 382 | .Dv NULL | ||
| 383 | on error. | ||
| 384 | .Pp | ||
| 385 | .Fn EC_GROUP_get_order , | ||
| 386 | .Fn EC_GROUP_get_cofactor , | ||
| 387 | .Fn EC_GROUP_get_curve_name , | ||
| 388 | .Fn EC_GROUP_get_asn1_flag , | ||
| 389 | .Fn EC_GROUP_get_point_conversion_form , | ||
| 390 | and | ||
| 391 | .Fn EC_GROUP_get_degree | ||
| 392 | return the order, cofactor, curve name (NID), ASN1 flag, | ||
| 393 | point_conversion_form and degree for the specified curve, respectively. | ||
| 394 | If there is no curve name associated with a curve then | ||
| 395 | .Fn EC_GROUP_get_curve_name | ||
| 396 | returns 0. | ||
| 397 | .Pp | ||
| 398 | .Fn EC_GROUP_get0_seed | ||
| 399 | returns a pointer to the seed that was used to generate the parameter | ||
| 400 | b, or | ||
| 401 | .Dv NULL | ||
| 402 | if the seed is not specified. | ||
| 403 | .Fn EC_GROUP_get_seed_len | ||
| 404 | returns the length of the seed or 0 if the seed is not specified. | ||
| 405 | .Pp | ||
| 406 | .Fn EC_GROUP_set_seed | ||
| 407 | returns the length of the seed that has been set. | ||
| 408 | If the supplied seed is | ||
| 409 | .Dv NULL | ||
| 410 | or the supplied seed length is 0, the return value will be 1. | ||
| 411 | On error 0 is returned. | ||
| 412 | .Pp | ||
| 413 | .Fn EC_GROUP_cmp | ||
| 414 | returns 0 if the curves are equal, 1 if they are not equal, | ||
| 415 | or -1 on error. | ||
| 416 | .Pp | ||
| 417 | .Fn EC_GROUP_get_basis_type | ||
| 418 | returns the values | ||
| 419 | .Dv NID_X9_62_tpBasis | ||
| 420 | or | ||
| 421 | .Dv NID_X9_62_ppBasis | ||
| 422 | as defined in | ||
| 423 | .In openssl/obj_mac.h | ||
| 424 | for a trinomial or pentanomial, respectively. | ||
| 425 | Alternatively in the event of an error a 0 is returned. | ||
| 426 | .Sh SEE ALSO | ||
| 427 | .Xr crypto 3 , | ||
| 428 | .Xr d2i_ECPKParameters 3 , | ||
| 429 | .Xr ec 3 , | ||
| 430 | .Xr EC_GFp_simple_method 3 , | ||
| 431 | .Xr EC_GROUP_new 3 , | ||
| 432 | .Xr EC_KEY_new 3 , | ||
| 433 | .Xr EC_POINT_add 3 , | ||
| 434 | .Xr EC_POINT_new 3 | ||
