1=pod 2 3=head1 NAME 4 5EC_KEY_get_method, EC_KEY_set_method, 6EC_KEY_new, EC_KEY_get_flags, EC_KEY_set_flags, EC_KEY_clear_flags, 7EC_KEY_new_by_curve_name, EC_KEY_free, EC_KEY_copy, EC_KEY_dup, EC_KEY_up_ref, 8EC_KEY_get0_engine, 9EC_KEY_get0_group, EC_KEY_set_group, EC_KEY_get0_private_key, 10EC_KEY_set_private_key, EC_KEY_get0_public_key, EC_KEY_set_public_key, 11EC_KEY_get_conv_form, 12EC_KEY_set_conv_form, EC_KEY_set_asn1_flag, 13EC_KEY_decoded_from_explicit_params, EC_KEY_precompute_mult, 14EC_KEY_generate_key, EC_KEY_check_key, EC_KEY_set_public_key_affine_coordinates, 15EC_KEY_oct2key, EC_KEY_key2buf, EC_KEY_oct2priv, EC_KEY_priv2oct, 16EC_KEY_priv2buf - Functions for creating, destroying and manipulating 17EC_KEY objects 18 19=head1 SYNOPSIS 20 21 #include <openssl/ec.h> 22 23 EC_KEY *EC_KEY_new(void); 24 int EC_KEY_get_flags(const EC_KEY *key); 25 void EC_KEY_set_flags(EC_KEY *key, int flags); 26 void EC_KEY_clear_flags(EC_KEY *key, int flags); 27 EC_KEY *EC_KEY_new_by_curve_name(int nid); 28 void EC_KEY_free(EC_KEY *key); 29 EC_KEY *EC_KEY_copy(EC_KEY *dst, const EC_KEY *src); 30 EC_KEY *EC_KEY_dup(const EC_KEY *src); 31 int EC_KEY_up_ref(EC_KEY *key); 32 ENGINE *EC_KEY_get0_engine(const EC_KEY *eckey); 33 const EC_GROUP *EC_KEY_get0_group(const EC_KEY *key); 34 int EC_KEY_set_group(EC_KEY *key, const EC_GROUP *group); 35 const BIGNUM *EC_KEY_get0_private_key(const EC_KEY *key); 36 int EC_KEY_set_private_key(EC_KEY *key, const BIGNUM *priv_key); 37 const EC_POINT *EC_KEY_get0_public_key(const EC_KEY *key); 38 int EC_KEY_set_public_key(EC_KEY *key, const EC_POINT *pub); 39 point_conversion_form_t EC_KEY_get_conv_form(const EC_KEY *key); 40 void EC_KEY_set_conv_form(EC_KEY *eckey, point_conversion_form_t cform); 41 void EC_KEY_set_asn1_flag(EC_KEY *eckey, int asn1_flag); 42 int EC_KEY_decoded_from_explicit_params(const EC_KEY *key); 43 int EC_KEY_precompute_mult(EC_KEY *key, BN_CTX *ctx); 44 int EC_KEY_generate_key(EC_KEY *key); 45 int EC_KEY_check_key(const EC_KEY *key); 46 int EC_KEY_set_public_key_affine_coordinates(EC_KEY *key, BIGNUM *x, BIGNUM *y); 47 const EC_KEY_METHOD *EC_KEY_get_method(const EC_KEY *key); 48 int EC_KEY_set_method(EC_KEY *key, const EC_KEY_METHOD *meth); 49 50 int EC_KEY_oct2key(EC_KEY *eckey, const unsigned char *buf, size_t len, BN_CTX *ctx); 51 size_t EC_KEY_key2buf(const EC_KEY *eckey, point_conversion_form_t form, 52 unsigned char **pbuf, BN_CTX *ctx); 53 54 int EC_KEY_oct2priv(EC_KEY *eckey, const unsigned char *buf, size_t len); 55 size_t EC_KEY_priv2oct(const EC_KEY *eckey, unsigned char *buf, size_t len); 56 57 size_t EC_KEY_priv2buf(const EC_KEY *eckey, unsigned char **pbuf); 58 59=head1 DESCRIPTION 60 61An EC_KEY represents a public key and, optionally, the associated private 62key. A new EC_KEY with no associated curve can be constructed by calling 63EC_KEY_new(). The reference count for the newly created EC_KEY is initially 64set to 1. A curve can be associated with the EC_KEY by calling 65EC_KEY_set_group(). 66 67Alternatively a new EC_KEY can be constructed by calling 68EC_KEY_new_by_curve_name() and supplying the nid of the associated curve. See 69L<EC_GROUP_new(3)> for a description of curve names. This function simply 70wraps calls to EC_KEY_new() and EC_GROUP_new_by_curve_name(). 71 72Calling EC_KEY_free() decrements the reference count for the EC_KEY object, 73and if it has dropped to zero then frees the memory associated with it. If 74B<key> is NULL nothing is done. 75 76EC_KEY_copy() copies the contents of the EC_KEY in B<src> into B<dest>. 77 78EC_KEY_dup() creates a new EC_KEY object and copies B<ec_key> into it. 79 80EC_KEY_up_ref() increments the reference count associated with the EC_KEY 81object. 82 83EC_KEY_get0_engine() returns a handle to the ENGINE that has been set for 84this EC_KEY object. 85 86EC_KEY_generate_key() generates a new public and private key for the supplied 87B<eckey> object. B<eckey> must have an EC_GROUP object associated with it 88before calling this function. The private key is a random integer (0 < priv_key 89< order, where I<order> is the order of the EC_GROUP object). The public key is 90an EC_POINT on the curve calculated by multiplying the generator for the 91curve by the private key. 92 93EC_KEY_check_key() performs various sanity checks on the EC_KEY object to 94confirm that it is valid. 95 96EC_KEY_set_public_key_affine_coordinates() sets the public key for B<key> based 97on its affine co-ordinates; i.e., it constructs an EC_POINT object based on 98the supplied B<x> and B<y> values and sets the public key to be this 99EC_POINT. It also performs certain sanity checks on the key to confirm 100that it is valid. 101 102The functions EC_KEY_get0_group(), EC_KEY_set_group(), 103EC_KEY_get0_private_key(), EC_KEY_set_private_key(), EC_KEY_get0_public_key(), 104and EC_KEY_set_public_key() get and set the EC_GROUP object, the private key, 105and the EC_POINT public key for the B<key> respectively. The function 106EC_KEY_set_private_key() accepts NULL as the priv_key argument to securely clear 107the private key component from the EC_KEY. 108 109The functions EC_KEY_get_conv_form() and EC_KEY_set_conv_form() get and set the 110point_conversion_form for the B<key>. For a description of 111point_conversion_forms please see L<EC_POINT_new(3)>. 112 113EC_KEY_set_flags() sets the flags in the B<flags> parameter on the EC_KEY 114object. Any flags that are already set are left set. The flags currently 115defined are EC_FLAG_NON_FIPS_ALLOW and EC_FLAG_FIPS_CHECKED. In 116addition there is the flag EC_FLAG_COFACTOR_ECDH which is specific to ECDH. 117EC_KEY_get_flags() returns the current flags that are set for this EC_KEY. 118EC_KEY_clear_flags() clears the flags indicated by the B<flags> parameter; all 119other flags are left in their existing state. 120 121EC_KEY_set_asn1_flag() sets the asn1_flag on the underlying EC_GROUP object 122(if set). Refer to L<EC_GROUP_copy(3)> for further information on the 123asn1_flag. 124 125EC_KEY_decoded_from_explicit_params() returns 1 if the group of the I<key> was 126decoded from data with explicitly encoded group parameters, -1 if the I<key> 127is NULL or the group parameters are missing, and 0 otherwise. 128 129EC_KEY_precompute_mult() stores multiples of the underlying EC_GROUP generator 130for faster point multiplication. See also L<EC_POINT_add(3)>. 131 132EC_KEY_oct2key() and EC_KEY_key2buf() are identical to the functions 133EC_POINT_oct2point() and EC_POINT_point2buf() except they use the public key 134EC_POINT in B<eckey>. 135 136EC_KEY_oct2priv() and EC_KEY_priv2oct() convert between the private key 137component of B<eckey> and octet form. The octet form consists of the content 138octets of the B<privateKey> OCTET STRING in an B<ECPrivateKey> ASN.1 structure. 139 140The function EC_KEY_priv2oct() must be supplied with a buffer long enough to 141store the octet form. The return value provides the number of octets stored. 142Calling the function with a NULL buffer will not perform the conversion but 143will just return the required buffer length. 144 145The function EC_KEY_priv2buf() allocates a buffer of suitable length and writes 146an EC_KEY to it in octet format. The allocated buffer is written to B<*pbuf> 147and its length is returned. The caller must free up the allocated buffer with a 148call to OPENSSL_free(). Since the allocated buffer value is written to B<*pbuf> 149the B<pbuf> parameter B<MUST NOT> be B<NULL>. 150 151EC_KEY_priv2buf() converts an EC_KEY private key into an allocated buffer. 152 153=head1 RETURN VALUES 154 155EC_KEY_new(), EC_KEY_new_by_curve_name() and EC_KEY_dup() return a pointer to 156the newly created EC_KEY object, or NULL on error. 157 158EC_KEY_get_flags() returns the flags associated with the EC_KEY object as an 159integer. 160 161EC_KEY_copy() returns a pointer to the destination key, or NULL on error. 162 163EC_KEY_get0_engine() returns a pointer to an ENGINE, or NULL if it wasn't set. 164 165EC_KEY_up_ref(), EC_KEY_set_group(), EC_KEY_set_public_key(), 166EC_KEY_precompute_mult(), EC_KEY_generate_key(), EC_KEY_check_key(), 167EC_KEY_set_public_key_affine_coordinates(), EC_KEY_oct2key() and 168EC_KEY_oct2priv() return 1 on success or 0 on error. 169 170EC_KEY_set_private_key() returns 1 on success or 0 on error except when the 171priv_key argument is NULL, in that case it returns 0, for legacy compatibility, 172and should not be treated as an error. 173 174EC_KEY_get0_group() returns the EC_GROUP associated with the EC_KEY. 175 176EC_KEY_get0_private_key() returns the private key associated with the EC_KEY. 177 178EC_KEY_get_conv_form() return the point_conversion_form for the EC_KEY. 179 180EC_KEY_key2buf(), EC_KEY_priv2oct() and EC_KEY_priv2buf() return the length 181of the buffer or 0 on error. 182 183=head1 SEE ALSO 184 185L<crypto(7)>, L<EC_GROUP_new(3)>, 186L<EC_GROUP_copy(3)>, L<EC_POINT_new(3)>, 187L<EC_POINT_add(3)>, 188L<EC_GFp_simple_method(3)>, 189L<d2i_ECPKParameters(3)> 190 191=head1 COPYRIGHT 192 193Copyright 2013-2022 The OpenSSL Project Authors. All Rights Reserved. 194 195Licensed under the OpenSSL license (the "License"). You may not use 196this file except in compliance with the License. You can obtain a copy 197in the file LICENSE in the source distribution or at 198L<https://www.openssl.org/source/license.html>. 199 200=cut 201