1=pod 2 3=head1 NAME 4 5EVP_PKEY_CTX_ctrl, 6EVP_PKEY_CTX_ctrl_str, 7EVP_PKEY_CTX_ctrl_uint64, 8EVP_PKEY_CTX_md, 9EVP_PKEY_CTX_set_signature_md, 10EVP_PKEY_CTX_get_signature_md, 11EVP_PKEY_CTX_set_mac_key, 12EVP_PKEY_CTX_set_group_name, 13EVP_PKEY_CTX_get_group_name, 14EVP_PKEY_CTX_set_rsa_padding, 15EVP_PKEY_CTX_get_rsa_padding, 16EVP_PKEY_CTX_set_rsa_pss_saltlen, 17EVP_PKEY_CTX_get_rsa_pss_saltlen, 18EVP_PKEY_CTX_set_rsa_keygen_bits, 19EVP_PKEY_CTX_set_rsa_keygen_pubexp, 20EVP_PKEY_CTX_set1_rsa_keygen_pubexp, 21EVP_PKEY_CTX_set_rsa_keygen_primes, 22EVP_PKEY_CTX_set_rsa_mgf1_md_name, 23EVP_PKEY_CTX_set_rsa_mgf1_md, 24EVP_PKEY_CTX_get_rsa_mgf1_md, 25EVP_PKEY_CTX_get_rsa_mgf1_md_name, 26EVP_PKEY_CTX_set_rsa_oaep_md_name, 27EVP_PKEY_CTX_set_rsa_oaep_md, 28EVP_PKEY_CTX_get_rsa_oaep_md, 29EVP_PKEY_CTX_get_rsa_oaep_md_name, 30EVP_PKEY_CTX_set0_rsa_oaep_label, 31EVP_PKEY_CTX_get0_rsa_oaep_label, 32EVP_PKEY_CTX_set_dsa_paramgen_bits, 33EVP_PKEY_CTX_set_dsa_paramgen_q_bits, 34EVP_PKEY_CTX_set_dsa_paramgen_md, 35EVP_PKEY_CTX_set_dsa_paramgen_md_props, 36EVP_PKEY_CTX_set_dsa_paramgen_gindex, 37EVP_PKEY_CTX_set_dsa_paramgen_type, 38EVP_PKEY_CTX_set_dsa_paramgen_seed, 39EVP_PKEY_CTX_set_dh_paramgen_prime_len, 40EVP_PKEY_CTX_set_dh_paramgen_subprime_len, 41EVP_PKEY_CTX_set_dh_paramgen_generator, 42EVP_PKEY_CTX_set_dh_paramgen_type, 43EVP_PKEY_CTX_set_dh_paramgen_gindex, 44EVP_PKEY_CTX_set_dh_paramgen_seed, 45EVP_PKEY_CTX_set_dh_rfc5114, 46EVP_PKEY_CTX_set_dhx_rfc5114, 47EVP_PKEY_CTX_set_dh_pad, 48EVP_PKEY_CTX_set_dh_nid, 49EVP_PKEY_CTX_set_dh_kdf_type, 50EVP_PKEY_CTX_get_dh_kdf_type, 51EVP_PKEY_CTX_set0_dh_kdf_oid, 52EVP_PKEY_CTX_get0_dh_kdf_oid, 53EVP_PKEY_CTX_set_dh_kdf_md, 54EVP_PKEY_CTX_get_dh_kdf_md, 55EVP_PKEY_CTX_set_dh_kdf_outlen, 56EVP_PKEY_CTX_get_dh_kdf_outlen, 57EVP_PKEY_CTX_set0_dh_kdf_ukm, 58EVP_PKEY_CTX_get0_dh_kdf_ukm, 59EVP_PKEY_CTX_set_ec_paramgen_curve_nid, 60EVP_PKEY_CTX_set_ec_param_enc, 61EVP_PKEY_CTX_set_ecdh_cofactor_mode, 62EVP_PKEY_CTX_get_ecdh_cofactor_mode, 63EVP_PKEY_CTX_set_ecdh_kdf_type, 64EVP_PKEY_CTX_get_ecdh_kdf_type, 65EVP_PKEY_CTX_set_ecdh_kdf_md, 66EVP_PKEY_CTX_get_ecdh_kdf_md, 67EVP_PKEY_CTX_set_ecdh_kdf_outlen, 68EVP_PKEY_CTX_get_ecdh_kdf_outlen, 69EVP_PKEY_CTX_set0_ecdh_kdf_ukm, 70EVP_PKEY_CTX_get0_ecdh_kdf_ukm, 71EVP_PKEY_CTX_set1_id, EVP_PKEY_CTX_get1_id, EVP_PKEY_CTX_get1_id_len, 72EVP_PKEY_CTX_set_kem_op 73- algorithm specific control operations 74 75=head1 SYNOPSIS 76 77 #include <openssl/evp.h> 78 79 int EVP_PKEY_CTX_ctrl(EVP_PKEY_CTX *ctx, int keytype, int optype, 80 int cmd, int p1, void *p2); 81 int EVP_PKEY_CTX_ctrl_uint64(EVP_PKEY_CTX *ctx, int keytype, int optype, 82 int cmd, uint64_t value); 83 int EVP_PKEY_CTX_ctrl_str(EVP_PKEY_CTX *ctx, const char *type, 84 const char *value); 85 86 int EVP_PKEY_CTX_md(EVP_PKEY_CTX *ctx, int optype, int cmd, const char *md); 87 88 int EVP_PKEY_CTX_set_signature_md(EVP_PKEY_CTX *ctx, const EVP_MD *md); 89 int EVP_PKEY_CTX_get_signature_md(EVP_PKEY_CTX *ctx, const EVP_MD **pmd); 90 91 int EVP_PKEY_CTX_set_mac_key(EVP_PKEY_CTX *ctx, const unsigned char *key, 92 int len); 93 int EVP_PKEY_CTX_set_group_name(EVP_PKEY_CTX *ctx, const char *name); 94 int EVP_PKEY_CTX_get_group_name(EVP_PKEY_CTX *ctx, char *name, size_t namelen); 95 96 int EVP_PKEY_CTX_set_kem_op(EVP_PKEY_CTX *ctx, const char *op); 97 98 #include <openssl/rsa.h> 99 100 int EVP_PKEY_CTX_set_rsa_padding(EVP_PKEY_CTX *ctx, int pad); 101 int EVP_PKEY_CTX_get_rsa_padding(EVP_PKEY_CTX *ctx, int *pad); 102 int EVP_PKEY_CTX_set_rsa_pss_saltlen(EVP_PKEY_CTX *ctx, int saltlen); 103 int EVP_PKEY_CTX_get_rsa_pss_saltlen(EVP_PKEY_CTX *ctx, int *saltlen); 104 int EVP_PKEY_CTX_set_rsa_keygen_bits(EVP_PKEY_CTX *ctx, int mbits); 105 int EVP_PKEY_CTX_set1_rsa_keygen_pubexp(EVP_PKEY_CTX *ctx, BIGNUM *pubexp); 106 int EVP_PKEY_CTX_set_rsa_keygen_primes(EVP_PKEY_CTX *ctx, int primes); 107 int EVP_PKEY_CTX_set_rsa_mgf1_md_name(EVP_PKEY_CTX *ctx, const char *mdname, 108 const char *mdprops); 109 int EVP_PKEY_CTX_set_rsa_mgf1_md(EVP_PKEY_CTX *ctx, const EVP_MD *md); 110 int EVP_PKEY_CTX_get_rsa_mgf1_md(EVP_PKEY_CTX *ctx, const EVP_MD **md); 111 int EVP_PKEY_CTX_get_rsa_mgf1_md_name(EVP_PKEY_CTX *ctx, char *name, 112 size_t namelen); 113 int EVP_PKEY_CTX_set_rsa_oaep_md_name(EVP_PKEY_CTX *ctx, const char *mdname, 114 const char *mdprops); 115 int EVP_PKEY_CTX_set_rsa_oaep_md(EVP_PKEY_CTX *ctx, const EVP_MD *md); 116 int EVP_PKEY_CTX_get_rsa_oaep_md(EVP_PKEY_CTX *ctx, const EVP_MD **md); 117 int EVP_PKEY_CTX_get_rsa_oaep_md_name(EVP_PKEY_CTX *ctx, char *name, 118 size_t namelen); 119 int EVP_PKEY_CTX_set0_rsa_oaep_label(EVP_PKEY_CTX *ctx, void *label, 120 int len); 121 int EVP_PKEY_CTX_get0_rsa_oaep_label(EVP_PKEY_CTX *ctx, unsigned char **label); 122 123 #include <openssl/dsa.h> 124 125 int EVP_PKEY_CTX_set_dsa_paramgen_bits(EVP_PKEY_CTX *ctx, int nbits); 126 int EVP_PKEY_CTX_set_dsa_paramgen_q_bits(EVP_PKEY_CTX *ctx, int qbits); 127 int EVP_PKEY_CTX_set_dsa_paramgen_md(EVP_PKEY_CTX *ctx, const EVP_MD *md); 128 int EVP_PKEY_CTX_set_dsa_paramgen_md_props(EVP_PKEY_CTX *ctx, 129 const char *md_name, 130 const char *md_properties); 131 int EVP_PKEY_CTX_set_dsa_paramgen_type(EVP_PKEY_CTX *ctx, const char *name); 132 int EVP_PKEY_CTX_set_dsa_paramgen_gindex(EVP_PKEY_CTX *ctx, int gindex); 133 int EVP_PKEY_CTX_set_dsa_paramgen_seed(EVP_PKEY_CTX *ctx, 134 const unsigned char *seed, 135 size_t seedlen); 136 137 #include <openssl/dh.h> 138 139 int EVP_PKEY_CTX_set_dh_paramgen_prime_len(EVP_PKEY_CTX *ctx, int len); 140 int EVP_PKEY_CTX_set_dh_paramgen_subprime_len(EVP_PKEY_CTX *ctx, int len); 141 int EVP_PKEY_CTX_set_dh_paramgen_generator(EVP_PKEY_CTX *ctx, int gen); 142 int EVP_PKEY_CTX_set_dh_paramgen_type(EVP_PKEY_CTX *ctx, int type); 143 int EVP_PKEY_CTX_set_dh_pad(EVP_PKEY_CTX *ctx, int pad); 144 int EVP_PKEY_CTX_set_dh_nid(EVP_PKEY_CTX *ctx, int nid); 145 int EVP_PKEY_CTX_set_dh_rfc5114(EVP_PKEY_CTX *ctx, int rfc5114); 146 int EVP_PKEY_CTX_set_dhx_rfc5114(EVP_PKEY_CTX *ctx, int rfc5114); 147 int EVP_PKEY_CTX_set_dh_paramgen_gindex(EVP_PKEY_CTX *ctx, int gindex); 148 int EVP_PKEY_CTX_set_dh_paramgen_seed(EVP_PKEY_CTX *ctx, 149 const unsigned char *seed, 150 size_t seedlen); 151 int EVP_PKEY_CTX_set_dh_kdf_type(EVP_PKEY_CTX *ctx, int kdf); 152 int EVP_PKEY_CTX_get_dh_kdf_type(EVP_PKEY_CTX *ctx); 153 int EVP_PKEY_CTX_set0_dh_kdf_oid(EVP_PKEY_CTX *ctx, ASN1_OBJECT *oid); 154 int EVP_PKEY_CTX_get0_dh_kdf_oid(EVP_PKEY_CTX *ctx, ASN1_OBJECT **oid); 155 int EVP_PKEY_CTX_set_dh_kdf_md(EVP_PKEY_CTX *ctx, const EVP_MD *md); 156 int EVP_PKEY_CTX_get_dh_kdf_md(EVP_PKEY_CTX *ctx, const EVP_MD **md); 157 int EVP_PKEY_CTX_set_dh_kdf_outlen(EVP_PKEY_CTX *ctx, int len); 158 int EVP_PKEY_CTX_get_dh_kdf_outlen(EVP_PKEY_CTX *ctx, int *len); 159 int EVP_PKEY_CTX_set0_dh_kdf_ukm(EVP_PKEY_CTX *ctx, unsigned char *ukm, int len); 160 161 #include <openssl/ec.h> 162 163 int EVP_PKEY_CTX_set_ec_paramgen_curve_nid(EVP_PKEY_CTX *ctx, int nid); 164 int EVP_PKEY_CTX_set_ec_param_enc(EVP_PKEY_CTX *ctx, int param_enc); 165 int EVP_PKEY_CTX_set_ecdh_cofactor_mode(EVP_PKEY_CTX *ctx, int cofactor_mode); 166 int EVP_PKEY_CTX_get_ecdh_cofactor_mode(EVP_PKEY_CTX *ctx); 167 int EVP_PKEY_CTX_set_ecdh_kdf_type(EVP_PKEY_CTX *ctx, int kdf); 168 int EVP_PKEY_CTX_get_ecdh_kdf_type(EVP_PKEY_CTX *ctx); 169 int EVP_PKEY_CTX_set_ecdh_kdf_md(EVP_PKEY_CTX *ctx, const EVP_MD *md); 170 int EVP_PKEY_CTX_get_ecdh_kdf_md(EVP_PKEY_CTX *ctx, const EVP_MD **md); 171 int EVP_PKEY_CTX_set_ecdh_kdf_outlen(EVP_PKEY_CTX *ctx, int len); 172 int EVP_PKEY_CTX_get_ecdh_kdf_outlen(EVP_PKEY_CTX *ctx, int *len); 173 int EVP_PKEY_CTX_set0_ecdh_kdf_ukm(EVP_PKEY_CTX *ctx, unsigned char *ukm, int len); 174 175 int EVP_PKEY_CTX_set1_id(EVP_PKEY_CTX *ctx, void *id, size_t id_len); 176 int EVP_PKEY_CTX_get1_id(EVP_PKEY_CTX *ctx, void *id); 177 int EVP_PKEY_CTX_get1_id_len(EVP_PKEY_CTX *ctx, size_t *id_len); 178 179The following functions have been deprecated since OpenSSL 3.0, and can be 180hidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value, 181see L<openssl_user_macros(7)>: 182 183 #include <openssl/rsa.h> 184 185 int EVP_PKEY_CTX_set_rsa_keygen_pubexp(EVP_PKEY_CTX *ctx, BIGNUM *pubexp); 186 187 #include <openssl/dh.h> 188 189 int EVP_PKEY_CTX_get0_dh_kdf_ukm(EVP_PKEY_CTX *ctx, unsigned char **ukm); 190 191 #include <openssl/ec.h> 192 193 int EVP_PKEY_CTX_get0_ecdh_kdf_ukm(EVP_PKEY_CTX *ctx, unsigned char **ukm); 194 195=head1 DESCRIPTION 196 197EVP_PKEY_CTX_ctrl() sends a control operation to the context I<ctx>. The key 198type used must match I<keytype> if it is not -1. The parameter I<optype> is a 199mask indicating which operations the control can be applied to. 200The control command is indicated in I<cmd> and any additional arguments in 201I<p1> and I<p2>. 202 203For I<cmd> = B<EVP_PKEY_CTRL_SET_MAC_KEY>, I<p1> is the length of the MAC key, 204and I<p2> is the MAC key. This is used by Poly1305, SipHash, HMAC and CMAC. 205 206Applications will not normally call EVP_PKEY_CTX_ctrl() directly but will 207instead call one of the algorithm specific functions below. 208 209EVP_PKEY_CTX_ctrl_uint64() is a wrapper that directly passes a 210uint64 value as I<p2> to EVP_PKEY_CTX_ctrl(). 211 212EVP_PKEY_CTX_ctrl_str() allows an application to send an algorithm 213specific control operation to a context I<ctx> in string form. This is 214intended to be used for options specified on the command line or in text 215files. The commands supported are documented in the openssl utility 216command line pages for the option I<-pkeyopt> which is supported by the 217I<pkeyutl>, I<genpkey> and I<req> commands. 218 219EVP_PKEY_CTX_md() sends a message digest control operation to the context 220I<ctx>. The message digest is specified by its name I<md>. 221 222EVP_PKEY_CTX_set_signature_md() sets the message digest type used 223in a signature. It can be used in the RSA, DSA and ECDSA algorithms. 224 225EVP_PKEY_CTX_get_signature_md()gets the message digest type used 226in a signature. It can be used in the RSA, DSA and ECDSA algorithms. 227 228Key generation typically involves setting up parameters to be used and 229generating the private and public key data. Some algorithm implementations 230allow private key data to be set explicitly using EVP_PKEY_CTX_set_mac_key(). 231In this case key generation is simply the process of setting up the 232parameters for the key and then setting the raw key data to the value explicitly. 233Normally applications would call L<EVP_PKEY_new_raw_private_key(3)> or similar 234functions instead. 235 236EVP_PKEY_CTX_set_mac_key() can be used with any of the algorithms supported by 237the L<EVP_PKEY_new_raw_private_key(3)> function. 238 239EVP_PKEY_CTX_set_group_name() sets the group name to I<name> for parameter and 240key generation. For example for EC keys this will set the curve name and for 241DH keys it will set the name of the finite field group. 242 243EVP_PKEY_CTX_get_group_name() finds the group name that's currently 244set with I<ctx>, and writes it to the location that I<name> points at, as long 245as its size I<namelen> is large enough to store that name, including a 246terminating NUL byte. 247 248=head2 RSA parameters 249 250EVP_PKEY_CTX_set_rsa_padding() sets the RSA padding mode for I<ctx>. 251The I<pad> parameter can take the value B<RSA_PKCS1_PADDING> for PKCS#1 252padding, B<RSA_NO_PADDING> for 253no padding, B<RSA_PKCS1_OAEP_PADDING> for OAEP padding (encrypt and 254decrypt only), B<RSA_X931_PADDING> for X9.31 padding (signature operations 255only), B<RSA_PKCS1_PSS_PADDING> (sign and verify only) and 256B<RSA_PKCS1_WITH_TLS_PADDING> for TLS RSA ClientKeyExchange message padding 257(decryption only). 258 259Two RSA padding modes behave differently if EVP_PKEY_CTX_set_signature_md() 260is used. If this function is called for PKCS#1 padding the plaintext buffer is 261an actual digest value and is encapsulated in a DigestInfo structure according 262to PKCS#1 when signing and this structure is expected (and stripped off) when 263verifying. If this control is not used with RSA and PKCS#1 padding then the 264supplied data is used directly and not encapsulated. In the case of X9.31 265padding for RSA the algorithm identifier byte is added or checked and removed 266if this control is called. If it is not called then the first byte of the plaintext 267buffer is expected to be the algorithm identifier byte. 268 269EVP_PKEY_CTX_get_rsa_padding() gets the RSA padding mode for I<ctx>. 270 271EVP_PKEY_CTX_set_rsa_pss_saltlen() sets the RSA PSS salt length to I<saltlen>. 272As its name implies it is only supported for PSS padding. If this function is 273not called then the maximum salt length is used when signing and auto detection 274when verifying. Three special values are supported: 275 276=over 4 277 278=item B<RSA_PSS_SALTLEN_DIGEST> 279 280sets the salt length to the digest length. 281 282=item B<RSA_PSS_SALTLEN_MAX> 283 284sets the salt length to the maximum permissible value. 285 286=item B<RSA_PSS_SALTLEN_AUTO> 287 288causes the salt length to be automatically determined based on the 289B<PSS> block structure when verifying. When signing, it has the same 290meaning as B<RSA_PSS_SALTLEN_MAX>. 291 292=back 293 294EVP_PKEY_CTX_get_rsa_pss_saltlen() gets the RSA PSS salt length for I<ctx>. 295The padding mode must already have been set to B<RSA_PKCS1_PSS_PADDING>. 296 297EVP_PKEY_CTX_set_rsa_keygen_bits() sets the RSA key length for 298RSA key generation to I<bits>. If not specified 2048 bits is used. 299 300EVP_PKEY_CTX_set1_rsa_keygen_pubexp() sets the public exponent value for RSA key 301generation to the value stored in I<pubexp>. Currently it should be an odd 302integer. In accordance with the OpenSSL naming convention, the I<pubexp> pointer 303must be freed independently of the EVP_PKEY_CTX (ie, it is internally copied). 304If not specified 65537 is used. 305 306EVP_PKEY_CTX_set_rsa_keygen_pubexp() does the same as 307EVP_PKEY_CTX_set1_rsa_keygen_pubexp() except that there is no internal copy and 308therefore I<pubexp> should not be modified or freed after the call. 309 310EVP_PKEY_CTX_set_rsa_keygen_primes() sets the number of primes for 311RSA key generation to I<primes>. If not specified 2 is used. 312 313EVP_PKEY_CTX_set_rsa_mgf1_md_name() sets the MGF1 digest for RSA 314padding schemes to the digest named I<mdname>. If the RSA algorithm 315implementation for the selected provider supports it then the digest will be 316fetched using the properties I<mdprops>. If not explicitly set the signing 317digest is used. The padding mode must have been set to B<RSA_PKCS1_OAEP_PADDING> 318or B<RSA_PKCS1_PSS_PADDING>. 319 320EVP_PKEY_CTX_set_rsa_mgf1_md() does the same as 321EVP_PKEY_CTX_set_rsa_mgf1_md_name() except that the name of the digest is 322inferred from the supplied I<md> and it is not possible to specify any 323properties. 324 325EVP_PKEY_CTX_get_rsa_mgf1_md_name() gets the name of the MGF1 326digest algorithm for I<ctx>. If not explicitly set the signing digest is used. 327The padding mode must have been set to B<RSA_PKCS1_OAEP_PADDING> or 328B<RSA_PKCS1_PSS_PADDING>. 329 330EVP_PKEY_CTX_get_rsa_mgf1_md() does the same as 331EVP_PKEY_CTX_get_rsa_mgf1_md_name() except that it returns a pointer to an 332EVP_MD object instead. Note that only known, built-in EVP_MD objects will be 333returned. The EVP_MD object may be NULL if the digest is not one of these (such 334as a digest only implemented in a third party provider). 335 336EVP_PKEY_CTX_set_rsa_oaep_md_name() sets the message digest type 337used in RSA OAEP to the digest named I<mdname>. If the RSA algorithm 338implementation for the selected provider supports it then the digest will be 339fetched using the properties I<mdprops>. The padding mode must have been set to 340B<RSA_PKCS1_OAEP_PADDING>. 341 342EVP_PKEY_CTX_set_rsa_oaep_md() does the same as 343EVP_PKEY_CTX_set_rsa_oaep_md_name() except that the name of the digest is 344inferred from the supplied I<md> and it is not possible to specify any 345properties. 346 347EVP_PKEY_CTX_get_rsa_oaep_md_name() gets the message digest 348algorithm name used in RSA OAEP and stores it in the buffer I<name> which is of 349size I<namelen>. The padding mode must have been set to 350B<RSA_PKCS1_OAEP_PADDING>. The buffer should be sufficiently large for any 351expected digest algorithm names or the function will fail. 352 353EVP_PKEY_CTX_get_rsa_oaep_md() does the same as 354EVP_PKEY_CTX_get_rsa_oaep_md_name() except that it returns a pointer to an 355EVP_MD object instead. Note that only known, built-in EVP_MD objects will be 356returned. The EVP_MD object may be NULL if the digest is not one of these (such 357as a digest only implemented in a third party provider). 358 359EVP_PKEY_CTX_set0_rsa_oaep_label() sets the RSA OAEP label to binary data 360I<label> and its length in bytes to I<len>. If I<label> is NULL or I<len> is 0, 361the label is cleared. The library takes ownership of the label so the 362caller should not free the original memory pointed to by I<label>. 363The padding mode must have been set to B<RSA_PKCS1_OAEP_PADDING>. 364 365EVP_PKEY_CTX_get0_rsa_oaep_label() gets the RSA OAEP label to 366I<label>. The return value is the label length. The padding mode 367must have been set to B<RSA_PKCS1_OAEP_PADDING>. The resulting pointer is owned 368by the library and should not be freed by the caller. 369 370B<RSA_PKCS1_WITH_TLS_PADDING> is used when decrypting an RSA encrypted TLS 371pre-master secret in a TLS ClientKeyExchange message. It is the same as 372RSA_PKCS1_PADDING except that it additionally verifies that the result is the 373correct length and the first two bytes are the protocol version initially 374requested by the client. If the encrypted content is publicly invalid then the 375decryption will fail. However, if the padding checks fail then decryption will 376still appear to succeed but a random TLS premaster secret will be returned 377instead. This padding mode accepts two parameters which can be set using the 378L<EVP_PKEY_CTX_set_params(3)> function. These are 379OSSL_ASYM_CIPHER_PARAM_TLS_CLIENT_VERSION and 380OSSL_ASYM_CIPHER_PARAM_TLS_NEGOTIATED_VERSION, both of which are expected to be 381unsigned integers. Normally only the first of these will be set and represents 382the TLS protocol version that was first requested by the client (e.g. 0x0303 for 383TLSv1.2, 0x0302 for TLSv1.1 etc). Historically some buggy clients would use the 384negotiated protocol version instead of the protocol version first requested. If 385this behaviour should be tolerated then 386OSSL_ASYM_CIPHER_PARAM_TLS_NEGOTIATED_VERSION should be set to the actual 387negotiated protocol version. Otherwise it should be left unset. 388 389=head2 DSA parameters 390 391EVP_PKEY_CTX_set_dsa_paramgen_bits() sets the number of bits used for DSA 392parameter generation to B<nbits>. If not specified, 2048 is used. 393 394EVP_PKEY_CTX_set_dsa_paramgen_q_bits() sets the number of bits in the subprime 395parameter I<q> for DSA parameter generation to I<qbits>. If not specified, 224 396is used. If a digest function is specified below, this parameter is ignored and 397instead, the number of bits in I<q> matches the size of the digest. 398 399EVP_PKEY_CTX_set_dsa_paramgen_md() sets the digest function used for DSA 400parameter generation to I<md>. If not specified, one of SHA-1, SHA-224, or 401SHA-256 is selected to match the bit length of I<q> above. 402 403EVP_PKEY_CTX_set_dsa_paramgen_md_props() sets the digest function used for DSA 404parameter generation using I<md_name> and I<md_properties> to retrieve the 405digest from a provider. 406If not specified, I<md_name> will be set to one of SHA-1, SHA-224, or 407SHA-256 depending on the bit length of I<q> above. I<md_properties> is a 408property query string that has a default value of '' if not specified. 409 410EVP_PKEY_CTX_set_dsa_paramgen_gindex() sets the I<gindex> used by the generator 411G. The default value is -1 which uses unverifiable g, otherwise a positive value 412uses verifiable g. This value must be saved if key validation of g is required, 413since it is not part of a persisted key. 414 415EVP_PKEY_CTX_set_dsa_paramgen_seed() sets the I<seed> to use for generation 416rather than using a randomly generated value for the seed. This is useful for 417testing purposes only and can fail if the seed does not produce primes for both 418p & q on its first iteration. This value must be saved if key validation of 419p, q, and verifiable g are required, since it is not part of a persisted key. 420 421EVP_PKEY_CTX_set_dsa_paramgen_type() sets the generation type to use FIPS186-4 422generation if I<name> is "fips186_4", or FIPS186-2 generation if I<name> is 423"fips186_2". The default value for the default provider is "fips186_2". The 424default value for the FIPS provider is "fips186_4". 425 426=head2 DH parameters 427 428EVP_PKEY_CTX_set_dh_paramgen_prime_len() sets the length of the DH prime 429parameter I<p> for DH parameter generation. If this function is not called then 4302048 is used. Only accepts lengths greater than or equal to 256. 431 432EVP_PKEY_CTX_set_dh_paramgen_subprime_len() sets the length of the DH 433optional subprime parameter I<q> for DH parameter generation. The default is 434256 if the prime is at least 2048 bits long or 160 otherwise. The DH paramgen 435type must have been set to "fips186_4". 436 437EVP_PKEY_CTX_set_dh_paramgen_generator() sets DH generator to I<gen> for DH 438parameter generation. If not specified 2 is used. 439 440EVP_PKEY_CTX_set_dh_paramgen_type() sets the key type for DH parameter 441generation. The supported parameters are: 442 443=over 4 444 445=item B<DH_PARAMGEN_TYPE_GROUP> 446 447Use a named group. If only the safe prime parameter I<p> is set this can be 448used to select a ffdhe safe prime group of the correct size. 449 450=item B<DH_PARAMGEN_TYPE_FIPS_186_4> 451 452FIPS186-4 FFC parameter generator. 453 454=item B<DH_PARAMGEN_TYPE_FIPS_186_2> 455 456FIPS186-2 FFC parameter generator (X9.42 DH). 457 458=item B<DH_PARAMGEN_TYPE_GENERATOR> 459 460Uses a safe prime generator g (PKCS#3 format). 461 462=back 463 464The default in the default provider is B<DH_PARAMGEN_TYPE_GENERATOR> for the 465"DH" keytype, and B<DH_PARAMGEN_TYPE_FIPS_186_2> for the "DHX" keytype. In the 466FIPS provider the default value is B<DH_PARAMGEN_TYPE_GROUP> for the "DH" 467keytype and <B<DH_PARAMGEN_TYPE_FIPS_186_4> for the "DHX" keytype. 468 469EVP_PKEY_CTX_set_dh_paramgen_gindex() sets the I<gindex> used by the generator G. 470The default value is -1 which uses unverifiable g, otherwise a positive value 471uses verifiable g. This value must be saved if key validation of g is required, 472since it is not part of a persisted key. 473 474EVP_PKEY_CTX_set_dh_paramgen_seed() sets the I<seed> to use for generation 475rather than using a randomly generated value for the seed. This is useful for 476testing purposes only and can fail if the seed does not produce primes for both 477p & q on its first iteration. This value must be saved if key validation of p, q, 478and verifiable g are required, since it is not part of a persisted key. 479 480EVP_PKEY_CTX_set_dh_pad() sets the DH padding mode. 481If I<pad> is 1 the shared secret is padded with zeros up to the size of the DH 482prime I<p>. 483If I<pad> is zero (the default) then no padding is performed. 484 485EVP_PKEY_CTX_set_dh_nid() sets the DH parameters to values corresponding to 486I<nid> as defined in RFC7919 or RFC3526. The I<nid> parameter must be 487B<NID_ffdhe2048>, B<NID_ffdhe3072>, B<NID_ffdhe4096>, B<NID_ffdhe6144>, 488B<NID_ffdhe8192>, B<NID_modp_1536>, B<NID_modp_2048>, B<NID_modp_3072>, 489B<NID_modp_4096>, B<NID_modp_6144>, B<NID_modp_8192> or B<NID_undef> to clear 490the stored value. This function can be called during parameter or key generation. 491The nid parameter and the rfc5114 parameter are mutually exclusive. 492 493EVP_PKEY_CTX_set_dh_rfc5114() and EVP_PKEY_CTX_set_dhx_rfc5114() both set the 494DH parameters to the values defined in RFC5114. The I<rfc5114> parameter must 495be 1, 2 or 3 corresponding to RFC5114 sections 2.1, 2.2 and 2.3. or 0 to clear 496the stored value. This macro can be called during parameter generation. The 497I<ctx> must have a key type of B<EVP_PKEY_DHX>. 498The rfc5114 parameter and the nid parameter are mutually exclusive. 499 500=head2 DH key derivation function parameters 501 502Note that all of the following functions require that the I<ctx> parameter has 503a private key type of B<EVP_PKEY_DHX>. When using key derivation, the output of 504EVP_PKEY_derive() is the output of the KDF instead of the DH shared secret. 505The KDF output is typically used as a Key Encryption Key (KEK) that in turn 506encrypts a Content Encryption Key (CEK). 507 508EVP_PKEY_CTX_set_dh_kdf_type() sets the key derivation function type to I<kdf> 509for DH key derivation. Possible values are B<EVP_PKEY_DH_KDF_NONE> and 510B<EVP_PKEY_DH_KDF_X9_42> which uses the key derivation specified in RFC2631 511(based on the keying algorithm described in X9.42). When using key derivation, 512the I<kdf_oid>, I<kdf_md> and I<kdf_outlen> parameters must also be specified. 513 514EVP_PKEY_CTX_get_dh_kdf_type() gets the key derivation function type for I<ctx> 515used for DH key derivation. Possible values are B<EVP_PKEY_DH_KDF_NONE> and 516B<EVP_PKEY_DH_KDF_X9_42>. 517 518EVP_PKEY_CTX_set0_dh_kdf_oid() sets the key derivation function object 519identifier to I<oid> for DH key derivation. This OID should identify the 520algorithm to be used with the Content Encryption Key. 521The library takes ownership of the object identifier so the caller should not 522free the original memory pointed to by I<oid>. 523 524EVP_PKEY_CTX_get0_dh_kdf_oid() gets the key derivation function oid for I<ctx> 525used for DH key derivation. The resulting pointer is owned by the library and 526should not be freed by the caller. 527 528EVP_PKEY_CTX_set_dh_kdf_md() sets the key derivation function message digest to 529I<md> for DH key derivation. Note that RFC2631 specifies that this digest should 530be SHA1 but OpenSSL tolerates other digests. 531 532EVP_PKEY_CTX_get_dh_kdf_md() gets the key derivation function message digest for 533I<ctx> used for DH key derivation. 534 535EVP_PKEY_CTX_set_dh_kdf_outlen() sets the key derivation function output length 536to I<len> for DH key derivation. 537 538EVP_PKEY_CTX_get_dh_kdf_outlen() gets the key derivation function output length 539for I<ctx> used for DH key derivation. 540 541EVP_PKEY_CTX_set0_dh_kdf_ukm() sets the user key material to I<ukm> and its 542length to I<len> for DH key derivation. This parameter is optional and 543corresponds to the partyAInfo field in RFC2631 terms. The specification 544requires that it is 512 bits long but this is not enforced by OpenSSL. 545The library takes ownership of the user key material so the caller should not 546free the original memory pointed to by I<ukm>. 547 548EVP_PKEY_CTX_get0_dh_kdf_ukm() gets the user key material for I<ctx>. 549The return value is the user key material length. The resulting pointer is owned 550by the library and should not be freed by the caller. 551 552=head2 EC parameters 553 554Use EVP_PKEY_CTX_set_group_name() (described above) to set the curve name to 555I<name> for parameter and key generation. 556 557EVP_PKEY_CTX_set_ec_paramgen_curve_nid() does the same as 558EVP_PKEY_CTX_set_group_name(), but is specific to EC and uses a I<nid> rather 559than a name string. 560 561For EC parameter generation, one of EVP_PKEY_CTX_set_group_name() 562or EVP_PKEY_CTX_set_ec_paramgen_curve_nid() must be called or an error occurs 563because there is no default curve. 564These function can also be called to set the curve explicitly when 565generating an EC key. 566 567EVP_PKEY_CTX_get_group_name() (described above) can be used to obtain the curve 568name that's currently set with I<ctx>. 569 570EVP_PKEY_CTX_set_ec_param_enc() sets the EC parameter encoding to I<param_enc> 571when generating EC parameters or an EC key. The encoding can be 572B<OPENSSL_EC_EXPLICIT_CURVE> for explicit parameters (the default in versions 573of OpenSSL before 1.1.0) or B<OPENSSL_EC_NAMED_CURVE> to use named curve form. 574For maximum compatibility the named curve form should be used. Note: the 575B<OPENSSL_EC_NAMED_CURVE> value was added in OpenSSL 1.1.0; previous 576versions should use 0 instead. 577 578=head2 ECDH parameters 579 580EVP_PKEY_CTX_set_ecdh_cofactor_mode() sets the cofactor mode to I<cofactor_mode> 581for ECDH key derivation. Possible values are 1 to enable cofactor 582key derivation, 0 to disable it and -1 to clear the stored cofactor mode and 583fallback to the private key cofactor mode. 584 585EVP_PKEY_CTX_get_ecdh_cofactor_mode() returns the cofactor mode for I<ctx> used 586for ECDH key derivation. Possible values are 1 when cofactor key derivation is 587enabled and 0 otherwise. 588 589=head2 ECDH key derivation function parameters 590 591EVP_PKEY_CTX_set_ecdh_kdf_type() sets the key derivation function type to 592I<kdf> for ECDH key derivation. Possible values are B<EVP_PKEY_ECDH_KDF_NONE> 593and B<EVP_PKEY_ECDH_KDF_X9_63> which uses the key derivation specified in X9.63. 594When using key derivation, the I<kdf_md> and I<kdf_outlen> parameters must 595also be specified. 596 597EVP_PKEY_CTX_get_ecdh_kdf_type() returns the key derivation function type for 598I<ctx> used for ECDH key derivation. Possible values are 599B<EVP_PKEY_ECDH_KDF_NONE> and B<EVP_PKEY_ECDH_KDF_X9_63>. 600 601EVP_PKEY_CTX_set_ecdh_kdf_md() sets the key derivation function message digest 602to I<md> for ECDH key derivation. Note that X9.63 specifies that this digest 603should be SHA1 but OpenSSL tolerates other digests. 604 605EVP_PKEY_CTX_get_ecdh_kdf_md() gets the key derivation function message digest 606for I<ctx> used for ECDH key derivation. 607 608EVP_PKEY_CTX_set_ecdh_kdf_outlen() sets the key derivation function output 609length to I<len> for ECDH key derivation. 610 611EVP_PKEY_CTX_get_ecdh_kdf_outlen() gets the key derivation function output 612length for I<ctx> used for ECDH key derivation. 613 614EVP_PKEY_CTX_set0_ecdh_kdf_ukm() sets the user key material to I<ukm> for ECDH 615key derivation. This parameter is optional and corresponds to the shared info in 616X9.63 terms. The library takes ownership of the user key material so the caller 617should not free the original memory pointed to by I<ukm>. 618 619EVP_PKEY_CTX_get0_ecdh_kdf_ukm() gets the user key material for I<ctx>. 620The return value is the user key material length. The resulting pointer is owned 621by the library and should not be freed by the caller. 622 623=head2 Other parameters 624 625EVP_PKEY_CTX_set1_id(), EVP_PKEY_CTX_get1_id() and EVP_PKEY_CTX_get1_id_len() 626are used to manipulate the special identifier field for specific signature 627algorithms such as SM2. The EVP_PKEY_CTX_set1_id() sets an ID pointed by I<id> with 628the length I<id_len> to the library. The library takes a copy of the id so that 629the caller can safely free the original memory pointed to by I<id>. 630EVP_PKEY_CTX_get1_id_len() returns the length of the ID set via a previous call 631to EVP_PKEY_CTX_set1_id(). The length is usually used to allocate adequate 632memory for further calls to EVP_PKEY_CTX_get1_id(). EVP_PKEY_CTX_get1_id() 633returns the previously set ID value to caller in I<id>. The caller should 634allocate adequate memory space for the I<id> before calling EVP_PKEY_CTX_get1_id(). 635 636EVP_PKEY_CTX_set_kem_op() sets the KEM operation to run. This can be set after 637EVP_PKEY_encapsulate_init() or EVP_PKEY_decapsulate_init() to select the 638kem operation. RSA is the only key type that supports encapsulation currently, 639and as there is no default operation for the RSA type, this function must be 640called before EVP_PKEY_encapsulate() or EVP_PKEY_decapsulate(). 641 642=head1 RETURN VALUES 643 644All other functions described on this page return a positive value for success 645and 0 or a negative value for failure. In particular a return value of -2 646indicates the operation is not supported by the public key algorithm. 647 648=head1 SEE ALSO 649 650L<EVP_PKEY_CTX_set_params(3)>, 651L<EVP_PKEY_CTX_new(3)>, 652L<EVP_PKEY_encrypt(3)>, 653L<EVP_PKEY_decrypt(3)>, 654L<EVP_PKEY_sign(3)>, 655L<EVP_PKEY_verify(3)>, 656L<EVP_PKEY_verify_recover(3)>, 657L<EVP_PKEY_derive(3)>, 658L<EVP_PKEY_keygen(3)> 659L<EVP_PKEY_encapsulate(3)> 660L<EVP_PKEY_decapsulate(3)> 661 662=head1 HISTORY 663 664EVP_PKEY_CTX_get_rsa_oaep_md_name(), EVP_PKEY_CTX_get_rsa_mgf1_md_name(), 665EVP_PKEY_CTX_set_rsa_mgf1_md_name(), EVP_PKEY_CTX_set_rsa_oaep_md_name(), 666EVP_PKEY_CTX_set_dsa_paramgen_md_props(), EVP_PKEY_CTX_set_dsa_paramgen_gindex(), 667EVP_PKEY_CTX_set_dsa_paramgen_type(), EVP_PKEY_CTX_set_dsa_paramgen_seed(), 668EVP_PKEY_CTX_set_group_name() and EVP_PKEY_CTX_get_group_name() 669were added in OpenSSL 3.0. 670 671The EVP_PKEY_CTX_set1_id(), EVP_PKEY_CTX_get1_id() and 672EVP_PKEY_CTX_get1_id_len() macros were added in 1.1.1, other functions were 673added in OpenSSL 1.0.0. 674 675In OpenSSL 1.1.1 and below the functions were mostly macros. 676From OpenSSL 3.0 they are all functions. 677 678EVP_PKEY_CTX_set_rsa_keygen_pubexp(), EVP_PKEY_CTX_get0_dh_kdf_ukm(), 679and EVP_PKEY_CTX_get0_ecdh_kdf_ukm() were deprecated in OpenSSL 3.0. 680 681=head1 COPYRIGHT 682 683Copyright 2006-2021 The OpenSSL Project Authors. All Rights Reserved. 684 685Licensed under the Apache License 2.0 (the "License"). You may not use 686this file except in compliance with the License. You can obtain a copy 687in the file LICENSE in the source distribution or at 688L<https://www.openssl.org/source/license.html>. 689 690=cut 691