- NAME
- SYNOPSIS
- DESCRIPTION
- RETURN VALUES
- SEE ALSO
- COPYRIGHT

# NAME

EC_KEY_get_method, EC_KEY_set_method, EC_KEY_new, EC_KEY_get_flags, EC_KEY_set_flags, EC_KEY_clear_flags, EC_KEY_new_by_curve_name, EC_KEY_free, EC_KEY_copy, EC_KEY_dup, EC_KEY_up_ref, EC_KEY_get0_group, EC_KEY_set_group, EC_KEY_get0_private_key, EC_KEY_set_private_key, EC_KEY_get0_public_key, EC_KEY_set_public_key, EC_KEY_get_conv_form, EC_KEY_set_conv_form, EC_KEY_set_asn1_flag, EC_KEY_precompute_mult, EC_KEY_generate_key, EC_KEY_check_key, EC_KEY_set_public_key_affine_coordinates, EC_KEY_oct2key, EC_KEY_key2buf, EC_KEY_oct2priv, EC_KEY_priv2oct, EC_KEY_priv2buf - Functions for creating, destroying and manipulating EC_KEY objects

# SYNOPSIS

     #include <openssl/ec.h>

     EC_KEY *EC_KEY_new(void);
     int EC_KEY_get_flags(const EC_KEY *key);
     void EC_KEY_set_flags(EC_KEY *key, int flags);
     void EC_KEY_clear_flags(EC_KEY *key, int flags);
     EC_KEY *EC_KEY_new_by_curve_name(int nid);
     void EC_KEY_free(EC_KEY *key);
     EC_KEY *EC_KEY_copy(EC_KEY *dst, const EC_KEY *src);
     EC_KEY *EC_KEY_dup(const EC_KEY *src);
     int EC_KEY_up_ref(EC_KEY *key);
     const EC_GROUP *EC_KEY_get0_group(const EC_KEY *key);
     int EC_KEY_set_group(EC_KEY *key, const EC_GROUP *group);
     const BIGNUM *EC_KEY_get0_private_key(const EC_KEY *key);
     int EC_KEY_set_private_key(EC_KEY *key, const BIGNUM *prv);
     const EC_POINT *EC_KEY_get0_public_key(const EC_KEY *key);
     int EC_KEY_set_public_key(EC_KEY *key, const EC_POINT *pub);
     point_conversion_form_t EC_KEY_get_conv_form(const EC_KEY *key);
     void EC_KEY_set_conv_form(EC_KEY *eckey, point_conversion_form_t cform);
     void EC_KEY_set_asn1_flag(EC_KEY *eckey, int asn1_flag);
     int EC_KEY_precompute_mult(EC_KEY *key, BN_CTX *ctx);
     int EC_KEY_generate_key(EC_KEY *key);
     int EC_KEY_check_key(const EC_KEY *key);
     int EC_KEY_set_public_key_affine_coordinates(EC_KEY *key,
                                                  BIGNUM *x, BIGNUM *y);
     const EC_KEY_METHOD *EC_KEY_get_method(const EC_KEY *key);
     int EC_KEY_set_method(EC_KEY *key, const EC_KEY_METHOD *meth);

     int EC_KEY_oct2key(EC_KEY *eckey, const unsigned char *buf, size_t len,
                        BN_CTX *ctx);
     size_t EC_KEY_key2buf(const EC_KEY *eckey, point_conversion_form_t form,
                           unsigned char **pbuf, BN_CTX *ctx);

     int EC_KEY_oct2priv(EC_KEY *eckey, const unsigned char *buf, size_t len);
     size_t EC_KEY_priv2oct(const EC_KEY *eckey, unsigned char *buf, size_t len);

     size_t EC_KEY_priv2buf(const EC_KEY *eckey, unsigned char **pbuf);

# DESCRIPTION

An EC_KEY represents a public key and, optionally, the associated private key. A new EC_KEY with no associated curve can be constructed by calling EC_KEY_new(). The reference count for the newly created EC_KEY is initially set to 1. A curve can be associated with the EC_KEY by calling EC_KEY_set_group().

Alternatively a new EC_KEY can be constructed by calling EC_KEY_new_by_curve_name() and supplying the nid of the associated curve. See EC_POINT_new(3).

EC_KEY_set_flags() sets the flags in the flags parameter on the EC_KEY object. Any flags that are already set are left set. The flags currently defined are EC_FLAG_NON_FIPS_ALLOW and EC_FLAG_FIPS_CHECKED. In addition there is the flag EC_FLAG_COFACTOR_ECDH which is specific to ECDH. EC_KEY_get_flags() returns the current flags that are set for this EC_KEY. EC_KEY_clear_flags() clears the flags indicated by the flags parameter; all other flags are left in their existing state.

EC_KEY_set_asn1_flag() sets the asn1_flag on the underlying EC_GROUP object (if set). Refer to EC_POINT_add(3).

EC_KEY_oct2key() and EC_KEY_key2buf() are identical to the functions EC_POINT_oct2point() and EC_KEY_point2buf() except they use the public key EC_POINT in eckey.

EC_KEY_oct2priv() and EC_KEY_priv2oct() convert between the private key component of eckey and octet form. The octet form consists of the content octets of the privateKey OCTET STRING in an ECPrivateKey ASN.1 structure.

The function EC_KEY_priv2oct() must be supplied with a buffer long enough to store the octet form. The return value provides the number of octets stored. Calling the function with a NULL buffer will not perform the conversion but will just return the required buffer length.

The function EC_KEY_priv2buf() allocates a buffer of suitable length and writes an EC_KEY to it in octet format. The allocated buffer is written to *pbuf and its length is returned. The caller must free up the allocated buffer with a call to OPENSSL_free(). Since the allocated buffer value is written to *pbuf the pbuf parameter MUST NOT be NULL.

EC_KEY_priv2buf() converts an EC_KEY private key into an allocated buffer.

# RETURN VALUES

EC_KEY_new(), EC_KEY_new_by_curve_name() and EC_KEY_dup() return a pointer to the newly created EC_KEY object, or NULL on error.

EC_KEY_get_flags() returns the flags associated with the EC_KEY object as an integer.

EC_KEY_copy() returns a pointer to the destination key, or NULL on error.

EC_KEY_up_ref(), EC_KEY_set_group(), EC_KEY_set_private_key(), EC_KEY_set_public_key(), EC_KEY_precompute_mult(), EC_KEY_generate_key(), EC_KEY_check_key(), EC_KEY_set_public_key_affine_coordinates(), EC_KEY_oct2key() and EC_KEY_oct2priv() return 1 on success or 0 on error.

EC_KEY_get0_group() returns the EC_GROUP associated with the EC_KEY.

EC_KEY_get0_private_key() returns the private key associated with the EC_KEY.

EC_KEY_get_conv_form() return the point_conversion_form for the EC_KEY.

EC_KEY_key2buf(), EC_KEY_priv2oct() and EC_KEY_priv2buf() return the length of the buffer or 0 on error.

# SEE ALSO

ec(3), EC_GROUP_copy(3), EC_POINT_add(3), d2i_ECPKParameters(3)

# COPYRIGHT

Copyright 2013-2016 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the OpenSSL license (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at https://www.openssl.org/source/license.html.