1=pod 2 3=head1 NAME 4 5EVP_EC_gen, 6EC_KEY_get_method, EC_KEY_set_method, EC_KEY_new_ex, 7EC_KEY_new, EC_KEY_get_flags, EC_KEY_set_flags, EC_KEY_clear_flags, 8EC_KEY_new_by_curve_name_ex, EC_KEY_new_by_curve_name, EC_KEY_free, 9EC_KEY_copy, EC_KEY_dup, EC_KEY_up_ref, EC_KEY_get0_engine, 10EC_KEY_get0_group, EC_KEY_set_group, EC_KEY_get0_private_key, 11EC_KEY_set_private_key, EC_KEY_get0_public_key, EC_KEY_set_public_key, 12EC_KEY_get_conv_form, 13EC_KEY_set_conv_form, EC_KEY_set_asn1_flag, 14EC_KEY_decoded_from_explicit_params, EC_KEY_precompute_mult, 15EC_KEY_generate_key, EC_KEY_check_key, EC_KEY_set_public_key_affine_coordinates, 16EC_KEY_oct2key, EC_KEY_key2buf, EC_KEY_oct2priv, EC_KEY_priv2oct, 17EC_KEY_priv2buf - Functions for creating, destroying and manipulating 18EC_KEY objects 19 20=head1 SYNOPSIS 21 22 #include <openssl/ec.h> 23 24 EVP_PKEY *EVP_EC_gen(const char *curve); 25 26The following functions have been deprecated since OpenSSL 3.0, and can be 27hidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value, 28see L<openssl_user_macros(7)>: 29 30 EC_KEY *EC_KEY_new_ex(OSSL_LIB_CTX *ctx, const char *propq); 31 EC_KEY *EC_KEY_new(void); 32 int EC_KEY_get_flags(const EC_KEY *key); 33 void EC_KEY_set_flags(EC_KEY *key, int flags); 34 void EC_KEY_clear_flags(EC_KEY *key, int flags); 35 EC_KEY *EC_KEY_new_by_curve_name_ex(OSSL_LIB_CTX *ctx, const char *propq, 36 int nid); 37 EC_KEY *EC_KEY_new_by_curve_name(int nid); 38 void EC_KEY_free(EC_KEY *key); 39 EC_KEY *EC_KEY_copy(EC_KEY *dst, const EC_KEY *src); 40 EC_KEY *EC_KEY_dup(const EC_KEY *src); 41 int EC_KEY_up_ref(EC_KEY *key); 42 ENGINE *EC_KEY_get0_engine(const EC_KEY *eckey); 43 const EC_GROUP *EC_KEY_get0_group(const EC_KEY *key); 44 int EC_KEY_set_group(EC_KEY *key, const EC_GROUP *group); 45 const BIGNUM *EC_KEY_get0_private_key(const EC_KEY *key); 46 int EC_KEY_set_private_key(EC_KEY *key, const BIGNUM *priv_key); 47 const EC_POINT *EC_KEY_get0_public_key(const EC_KEY *key); 48 int EC_KEY_set_public_key(EC_KEY *key, const EC_POINT *pub); 49 point_conversion_form_t EC_KEY_get_conv_form(const EC_KEY *key); 50 void EC_KEY_set_conv_form(EC_KEY *eckey, point_conversion_form_t cform); 51 void EC_KEY_set_asn1_flag(EC_KEY *eckey, int asn1_flag); 52 int EC_KEY_decoded_from_explicit_params(const EC_KEY *key); 53 int EC_KEY_generate_key(EC_KEY *key); 54 int EC_KEY_check_key(const EC_KEY *key); 55 int EC_KEY_set_public_key_affine_coordinates(EC_KEY *key, BIGNUM *x, BIGNUM *y); 56 const EC_KEY_METHOD *EC_KEY_get_method(const EC_KEY *key); 57 int EC_KEY_set_method(EC_KEY *key, const EC_KEY_METHOD *meth); 58 59 int EC_KEY_oct2key(EC_KEY *eckey, const unsigned char *buf, size_t len, BN_CTX *ctx); 60 size_t EC_KEY_key2buf(const EC_KEY *eckey, point_conversion_form_t form, 61 unsigned char **pbuf, BN_CTX *ctx); 62 63 int EC_KEY_oct2priv(EC_KEY *eckey, const unsigned char *buf, size_t len); 64 size_t EC_KEY_priv2oct(const EC_KEY *eckey, unsigned char *buf, size_t len); 65 66 size_t EC_KEY_priv2buf(const EC_KEY *eckey, unsigned char **pbuf); 67 int EC_KEY_precompute_mult(EC_KEY *key, BN_CTX *ctx); 68 69=head1 DESCRIPTION 70 71EVP_EC_gen() generates a new EC key pair on the given I<curve>. 72 73All of the functions described below are deprecated. 74Applications should instead use EVP_EC_gen(), L<EVP_PKEY_Q_keygen(3)>, or 75L<EVP_PKEY_keygen_init(3)> and L<EVP_PKEY_keygen(3)>. 76 77An EC_KEY represents a public key and, optionally, the associated private 78key. 79A new EC_KEY with no associated curve can be constructed by calling 80EC_KEY_new_ex() and specifying the associated library context in I<ctx> 81(see L<OSSL_LIB_CTX(3)>) and property query string I<propq>. 82The I<ctx> parameter may be NULL in which case the default library context is 83used. 84The reference count for the newly created EC_KEY is initially 85set to 1. 86A curve can be associated with the EC_KEY by calling 87EC_KEY_set_group(). 88 89EC_KEY_new() is the same as EC_KEY_new_ex() except that the default library 90context is always used. 91 92Alternatively a new EC_KEY can be constructed by calling 93EC_KEY_new_by_curve_name_ex() and supplying the nid of the associated 94curve, the library context to be used I<ctx> (see L<OSSL_LIB_CTX(3)>) and any 95property query string I<propq>. 96The I<ctx> parameter may be NULL in which case the default library context is 97used. The I<propq> value may also be NULL. 98See L<EC_GROUP_new(3)> for a description of curve names. 99This function simply wraps calls to EC_KEY_new_ex() and 100EC_GROUP_new_by_curve_name_ex(). 101 102EC_KEY_new_by_curve_name() is the same as EC_KEY_new_by_curve_name_ex() 103except that the default library context is always used and a NULL property query 104string. 105 106Calling EC_KEY_free() decrements the reference count for the EC_KEY object, 107and if it has dropped to zero then frees the memory associated with it. If 108I<key> is NULL nothing is done. 109 110EC_KEY_copy() copies the contents of the EC_KEY in I<src> into I<dest>. 111 112EC_KEY_dup() creates a new EC_KEY object and copies I<ec_key> into it. 113 114EC_KEY_up_ref() increments the reference count associated with the EC_KEY 115object. 116 117EC_KEY_get0_engine() returns a handle to the ENGINE that has been set for 118this EC_KEY object. 119 120EC_KEY_generate_key() generates a new public and private key for the supplied 121I<eckey> object. I<eckey> must have an EC_GROUP object associated with it 122before calling this function. The private key is a random integer (0 < priv_key 123< order, where I<order> is the order of the EC_GROUP object). The public key is 124an EC_POINT on the curve calculated by multiplying the generator for the 125curve by the private key. 126 127EC_KEY_check_key() performs various sanity checks on the EC_KEY object to 128confirm that it is valid. 129 130EC_KEY_set_public_key_affine_coordinates() sets the public key for I<key> based 131on its affine coordinates; i.e., it constructs an EC_POINT object based on 132the supplied I<x> and I<y> values and sets the public key to be this 133EC_POINT. It also performs certain sanity checks on the key to confirm 134that it is valid. 135 136The functions EC_KEY_get0_group(), EC_KEY_set_group(), 137EC_KEY_get0_private_key(), EC_KEY_set_private_key(), EC_KEY_get0_public_key(), 138and EC_KEY_set_public_key() get and set the EC_GROUP object, the private key, 139and the EC_POINT public key for the B<key> respectively. The function 140EC_KEY_set_private_key() accepts NULL as the priv_key argument to securely clear 141the private key component from the EC_KEY. 142 143The functions EC_KEY_get_conv_form() and EC_KEY_set_conv_form() get and set the 144point_conversion_form for the I<key>. For a description of 145point_conversion_forms please see L<EC_POINT_new(3)>. 146 147EC_KEY_set_flags() sets the flags in the I<flags> parameter on the EC_KEY 148object. Any flags that are already set are left set. The flags currently 149defined are EC_FLAG_NON_FIPS_ALLOW and EC_FLAG_FIPS_CHECKED. In 150addition there is the flag EC_FLAG_COFACTOR_ECDH which is specific to ECDH. 151EC_KEY_get_flags() returns the current flags that are set for this EC_KEY. 152EC_KEY_clear_flags() clears the flags indicated by the I<flags> parameter; all 153other flags are left in their existing state. 154 155EC_KEY_set_asn1_flag() sets the asn1_flag on the underlying EC_GROUP object 156(if set). Refer to L<EC_GROUP_copy(3)> for further information on the 157asn1_flag. 158 159EC_KEY_decoded_from_explicit_params() returns 1 if the group of the I<key> was 160decoded from data with explicitly encoded group parameters, -1 if the I<key> 161is NULL or the group parameters are missing, and 0 otherwise. 162 163EC_KEY_precompute_mult() stores multiples of the underlying EC_GROUP generator 164for faster point multiplication. See also L<EC_POINT_add(3)>. 165Modern versions should instead switch to named curves which OpenSSL has 166hardcoded lookup tables for. 167 168EC_KEY_oct2key() and EC_KEY_key2buf() are identical to the functions 169EC_POINT_oct2point() and EC_POINT_point2buf() except they use the public key 170EC_POINT in I<eckey>. 171 172EC_KEY_oct2priv() and EC_KEY_priv2oct() convert between the private key 173component of I<eckey> and octet form. The octet form consists of the content 174octets of the I<privateKey> OCTET STRING in an I<ECPrivateKey> ASN.1 structure. 175 176The function EC_KEY_priv2oct() must be supplied with a buffer long enough to 177store the octet form. The return value provides the number of octets stored. 178Calling the function with a NULL buffer will not perform the conversion but 179will just return the required buffer length. 180 181The function EC_KEY_priv2buf() allocates a buffer of suitable length and writes 182an EC_KEY to it in octet format. The allocated buffer is written to I<*pbuf> 183and its length is returned. The caller must free up the allocated buffer with a 184call to OPENSSL_free(). Since the allocated buffer value is written to I<*pbuf> 185the I<pbuf> parameter B<MUST NOT> be B<NULL>. 186 187EC_KEY_priv2buf() converts an EC_KEY private key into an allocated buffer. 188 189=head1 RETURN VALUES 190 191EC_KEY_new_ex(), EC_KEY_new(), EC_KEY_new_by_curve_name_ex(), 192EC_KEY_new_by_curve_name() and EC_KEY_dup() return a pointer to the newly 193created EC_KEY object, or NULL on error. 194 195EC_KEY_get_flags() returns the flags associated with the EC_KEY object as an 196integer. 197 198EC_KEY_copy() returns a pointer to the destination key, or NULL on error. 199 200EC_KEY_get0_engine() returns a pointer to an ENGINE, or NULL if it wasn't set. 201 202EC_KEY_up_ref(), EC_KEY_set_group(), EC_KEY_set_public_key(), 203EC_KEY_precompute_mult(), EC_KEY_generate_key(), EC_KEY_check_key(), 204EC_KEY_set_public_key_affine_coordinates(), EC_KEY_oct2key() and 205EC_KEY_oct2priv() return 1 on success or 0 on error. 206 207EC_KEY_set_private_key() returns 1 on success or 0 on error except when the 208priv_key argument is NULL, in that case it returns 0, for legacy compatibility, 209and should not be treated as an error. 210 211EC_KEY_get0_group() returns the EC_GROUP associated with the EC_KEY. 212 213EC_KEY_get0_private_key() returns the private key associated with the EC_KEY. 214 215EC_KEY_get_conv_form() return the point_conversion_form for the EC_KEY. 216 217EC_KEY_key2buf(), EC_KEY_priv2oct() and EC_KEY_priv2buf() return the length 218of the buffer or 0 on error. 219 220=head1 SEE ALSO 221 222L<EVP_PKEY_Q_keygen(3)> 223L<crypto(7)>, L<EC_GROUP_new(3)>, 224L<EC_GROUP_copy(3)>, L<EC_POINT_new(3)>, 225L<EC_POINT_add(3)>, 226L<EC_GFp_simple_method(3)>, 227L<d2i_ECPKParameters(3)>, 228L<OSSL_LIB_CTX(3)> 229 230=head1 HISTORY 231 232EVP_EC_gen() was added in OpenSSL 3.0. 233All other functions described here were deprecated in OpenSSL 3.0. 234For replacement see L<EVP_PKEY-EC(7)>. 235 236=head1 COPYRIGHT 237 238Copyright 2013-2023 The OpenSSL Project Authors. All Rights Reserved. 239 240Licensed under the Apache License 2.0 (the "License"). You may not use 241this file except in compliance with the License. You can obtain a copy 242in the file LICENSE in the source distribution or at 243L<https://www.openssl.org/source/license.html>. 244 245=cut 246