1=pod 2 3=head1 NAME 4 5EVP_PKEY_CTX_ctrl, 6EVP_PKEY_CTX_ctrl_str, 7EVP_PKEY_CTX_set_signature_md, 8EVP_PKEY_CTX_get_signature_md, 9EVP_PKEY_CTX_set_mac_key, 10EVP_PKEY_CTX_set_rsa_padding, 11EVP_PKEY_CTX_set_rsa_pss_saltlen, 12EVP_PKEY_CTX_set_rsa_keygen_bits, 13EVP_PKEY_CTX_set_rsa_keygen_pubexp, 14EVP_PKEY_CTX_set_dsa_paramgen_bits, 15EVP_PKEY_CTX_set_dh_paramgen_prime_len, 16EVP_PKEY_CTX_set_dh_paramgen_generator, 17EVP_PKEY_CTX_set_dh_pad, 18EVP_PKEY_CTX_set_dh_nid, 19EVP_PKEY_CTX_set_ec_paramgen_curve_nid, 20EVP_PKEY_CTX_set_ec_param_enc, 21EVP_PKEY_CTX_set1_id, EVP_PKEY_CTX_get1_id, EVP_PKEY_CTX_get1_id_len 22- algorithm specific control operations 23 24=head1 SYNOPSIS 25 26 #include <openssl/evp.h> 27 28 int EVP_PKEY_CTX_ctrl(EVP_PKEY_CTX *ctx, int keytype, int optype, 29 int cmd, int p1, void *p2); 30 int EVP_PKEY_CTX_ctrl_str(EVP_PKEY_CTX *ctx, const char *type, 31 const char *value); 32 33 int EVP_PKEY_CTX_set_signature_md(EVP_PKEY_CTX *ctx, const EVP_MD *md); 34 int EVP_PKEY_CTX_get_signature_md(EVP_PKEY_CTX *ctx, const EVP_MD **pmd); 35 36 int EVP_PKEY_CTX_set_mac_key(EVP_PKEY_CTX *ctx, unsigned char *key, int len); 37 38 #include <openssl/rsa.h> 39 40 int EVP_PKEY_CTX_set_rsa_padding(EVP_PKEY_CTX *ctx, int pad); 41 int EVP_PKEY_CTX_set_rsa_pss_saltlen(EVP_PKEY_CTX *ctx, int len); 42 int EVP_PKEY_CTX_set_rsa_keygen_bits(EVP_PKEY_CTX *ctx, int mbits); 43 int EVP_PKEY_CTX_set_rsa_keygen_pubexp(EVP_PKEY_CTX *ctx, BIGNUM *pubexp); 44 45 #include <openssl/dsa.h> 46 int EVP_PKEY_CTX_set_dsa_paramgen_bits(EVP_PKEY_CTX *ctx, int nbits); 47 48 #include <openssl/dh.h> 49 int EVP_PKEY_CTX_set_dh_paramgen_prime_len(EVP_PKEY_CTX *ctx, int len); 50 int EVP_PKEY_CTX_set_dh_paramgen_generator(EVP_PKEY_CTX *ctx, int gen); 51 int EVP_PKEY_CTX_set_dh_pad(EVP_PKEY_CTX *ctx, int pad); 52 int EVP_PKEY_CTX_set_dh_nid(EVP_PKEY_CTX *ctx, int nid); 53 54 #include <openssl/ec.h> 55 int EVP_PKEY_CTX_set_ec_paramgen_curve_nid(EVP_PKEY_CTX *ctx, int nid); 56 int EVP_PKEY_CTX_set_ec_param_enc(EVP_PKEY_CTX *ctx, int param_enc); 57 58 int EVP_PKEY_CTX_set1_id(EVP_PKEY_CTX *ctx, void *id, size_t id_len); 59 int EVP_PKEY_CTX_get1_id(EVP_PKEY_CTX *ctx, void *id); 60 int EVP_PKEY_CTX_get1_id_len(EVP_PKEY_CTX *ctx, size_t *id_len); 61 62=head1 DESCRIPTION 63 64The function EVP_PKEY_CTX_ctrl() sends a control operation to the context 65B<ctx>. The key type used must match B<keytype> if it is not -1. The parameter 66B<optype> is a mask indicating which operations the control can be applied to. 67The control command is indicated in B<cmd> and any additional arguments in 68B<p1> and B<p2>. 69 70For B<cmd> = B<EVP_PKEY_CTRL_SET_MAC_KEY>, B<p1> is the length of the MAC key, 71and B<p2> is MAC key. This is used by Poly1305, SipHash, HMAC and CMAC. 72 73Applications will not normally call EVP_PKEY_CTX_ctrl() directly but will 74instead call one of the algorithm specific macros below. 75 76The function EVP_PKEY_CTX_ctrl_str() allows an application to send an algorithm 77specific control operation to a context B<ctx> in string form. This is 78intended to be used for options specified on the command line or in text 79files. The commands supported are documented in the openssl utility 80command line pages for the option B<-pkeyopt> which is supported by the 81B<pkeyutl>, B<genpkey> and B<req> commands. 82 83All the remaining "functions" are implemented as macros. 84 85The EVP_PKEY_CTX_set_signature_md() macro sets the message digest type used 86in a signature. It can be used in the RSA, DSA and ECDSA algorithms. 87 88The EVP_PKEY_CTX_get_signature_md() macro gets the message digest type used in a 89signature. It can be used in the RSA, DSA and ECDSA algorithms. 90 91Key generation typically involves setting up parameters to be used and 92generating the private and public key data. Some algorithm implementations 93allow private key data to be set explicitly using the EVP_PKEY_CTX_set_mac_key() 94macro. In this case key generation is simply the process of setting up the 95parameters for the key and then setting the raw key data to the value explicitly 96provided by that macro. Normally applications would call 97L<EVP_PKEY_new_raw_private_key(3)> or similar functions instead of this macro. 98 99The EVP_PKEY_CTX_set_mac_key() macro can be used with any of the algorithms 100supported by the L<EVP_PKEY_new_raw_private_key(3)> function. 101 102The macro EVP_PKEY_CTX_set_rsa_padding() sets the RSA padding mode for B<ctx>. 103The B<pad> parameter can take the value RSA_PKCS1_PADDING for PKCS#1 padding, 104RSA_SSLV23_PADDING for SSLv23 padding, RSA_NO_PADDING for no padding, 105RSA_PKCS1_OAEP_PADDING for OAEP padding (encrypt and decrypt only), 106RSA_X931_PADDING for X9.31 padding (signature operations only) and 107RSA_PKCS1_PSS_PADDING (sign and verify only). 108 109Two RSA padding modes behave differently if EVP_PKEY_CTX_set_signature_md() 110is used. If this macro is called for PKCS#1 padding the plaintext buffer is 111an actual digest value and is encapsulated in a DigestInfo structure according 112to PKCS#1 when signing and this structure is expected (and stripped off) when 113verifying. If this control is not used with RSA and PKCS#1 padding then the 114supplied data is used directly and not encapsulated. In the case of X9.31 115padding for RSA the algorithm identifier byte is added or checked and removed 116if this control is called. If it is not called then the first byte of the plaintext 117buffer is expected to be the algorithm identifier byte. 118 119The EVP_PKEY_CTX_set_rsa_pss_saltlen() macro sets the RSA PSS salt length to 120B<len> as its name implies it is only supported for PSS padding. Three special 121values are supported: RSA_PSS_SALTLEN_DIGEST sets the salt length to the 122digest length, RSA_PSS_SALTLEN_MAX sets the salt length to the maximum 123permissible value. When verifying RSA_PSS_SALTLEN_AUTO causes the salt length 124to be automatically determined based on the B<PSS> block structure. If this 125macro is not called maximum salt length is used when signing and auto detection 126when verifying is used by default. 127 128The EVP_PKEY_CTX_set_rsa_keygen_bits() macro sets the RSA key length for 129RSA key generation to B<bits>. If not specified 1024 bits is used. 130 131The EVP_PKEY_CTX_set_rsa_keygen_pubexp() macro sets the public exponent value 132for RSA key generation to B<pubexp> currently it should be an odd integer. The 133B<pubexp> pointer is used internally by this function so it should not be 134modified or free after the call. If this macro is not called then 65537 is used. 135 136The macro EVP_PKEY_CTX_set_dsa_paramgen_bits() sets the number of bits used 137for DSA parameter generation to B<bits>. If not specified 1024 is used. 138 139The macro EVP_PKEY_CTX_set_dh_paramgen_prime_len() sets the length of the DH 140prime parameter B<p> for DH parameter generation. If this macro is not called 141then 1024 is used. 142 143The EVP_PKEY_CTX_set_dh_paramgen_generator() macro sets DH generator to B<gen> 144for DH parameter generation. If not specified 2 is used. 145 146The EVP_PKEY_CTX_set_dh_pad() macro sets the DH padding mode. If B<pad> is 1471 the shared secret is padded with zeroes up to the size of the DH prime B<p>. 148If B<pad> is zero (the default) then no padding is performed. 149 150EVP_PKEY_CTX_set_dh_nid() sets the DH parameters to values corresponding to 151B<nid>. The B<nid> parameter must be B<NID_ffdhe2048>, B<NID_ffdhe3072>, 152B<NID_ffdhe4096>, B<NID_ffdhe6144> or B<NID_ffdhe8192>. This macro can be 153called during parameter or key generation. 154 155The EVP_PKEY_CTX_set_ec_paramgen_curve_nid() sets the EC curve for EC parameter 156generation to B<nid>. For EC parameter generation this macro must be called 157or an error occurs because there is no default curve. 158This function can also be called to set the curve explicitly when 159generating an EC key. 160 161The EVP_PKEY_CTX_set_ec_param_enc() sets the EC parameter encoding to 162B<param_enc> when generating EC parameters or an EC key. The encoding can be 163B<OPENSSL_EC_EXPLICIT_CURVE> for explicit parameters (the default in versions 164of OpenSSL before 1.1.0) or B<OPENSSL_EC_NAMED_CURVE> to use named curve form. 165For maximum compatibility the named curve form should be used. Note: the 166B<OPENSSL_EC_NAMED_CURVE> value was only added to OpenSSL 1.1.0; previous 167versions should use 0 instead. 168 169The EVP_PKEY_CTX_set1_id(), EVP_PKEY_CTX_get1_id() and EVP_PKEY_CTX_get1_id_len() 170macros are used to manipulate the special identifier field for specific signature 171algorithms such as SM2. The EVP_PKEY_CTX_set1_id() sets an ID pointed by B<id> with 172the length B<id_len> to the library. The library takes a copy of the id so that 173the caller can safely free the original memory pointed to by B<id>. The 174EVP_PKEY_CTX_get1_id_len() macro returns the length of the ID set via a previous 175call to EVP_PKEY_CTX_set1_id(). The length is usually used to allocate adequate 176memory for further calls to EVP_PKEY_CTX_get1_id(). The EVP_PKEY_CTX_get1_id() 177macro returns the previously set ID value to caller in B<id>. The caller should 178allocate adequate memory space for the B<id> before calling EVP_PKEY_CTX_get1_id(). 179 180=head1 RETURN VALUES 181 182EVP_PKEY_CTX_ctrl() and its macros return a positive value for success and 0 183or a negative value for failure. In particular a return value of -2 184indicates the operation is not supported by the public key algorithm. 185 186=head1 SEE ALSO 187 188L<EVP_PKEY_CTX_new(3)>, 189L<EVP_PKEY_encrypt(3)>, 190L<EVP_PKEY_decrypt(3)>, 191L<EVP_PKEY_sign(3)>, 192L<EVP_PKEY_verify(3)>, 193L<EVP_PKEY_verify_recover(3)>, 194L<EVP_PKEY_derive(3)> 195L<EVP_PKEY_keygen(3)> 196 197=head1 HISTORY 198 199EVP_PKEY_CTX_set1_id(), EVP_PKEY_CTX_get1_id() and EVP_PKEY_CTX_get1_id_len() 200macros were added in 1.1.1, other functions were first added to OpenSSL 1.0.0. 201 202=head1 COPYRIGHT 203 204Copyright 2006-2018 The OpenSSL Project Authors. All Rights Reserved. 205 206Licensed under the OpenSSL license (the "License"). You may not use 207this file except in compliance with the License. You can obtain a copy 208in the file LICENSE in the source distribution or at 209L<https://www.openssl.org/source/license.html>. 210 211=cut 212