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
26Deprecated since OpenSSL 3.0, can be hidden entirely by defining
27B<OPENSSL_API_COMPAT> with a suitable version value, see
28L<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 *prv);
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 co-ordinates; 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 I<key> respectively.
140
141The functions EC_KEY_get_conv_form() and EC_KEY_set_conv_form() get and set the
142point_conversion_form for the I<key>. For a description of
143point_conversion_forms please see L<EC_POINT_new(3)>.
144
145EC_KEY_set_flags() sets the flags in the I<flags> parameter on the EC_KEY
146object. Any flags that are already set are left set. The flags currently
147defined are EC_FLAG_NON_FIPS_ALLOW and EC_FLAG_FIPS_CHECKED. In
148addition there is the flag EC_FLAG_COFACTOR_ECDH which is specific to ECDH.
149EC_KEY_get_flags() returns the current flags that are set for this EC_KEY.
150EC_KEY_clear_flags() clears the flags indicated by the I<flags> parameter; all
151other flags are left in their existing state.
152
153EC_KEY_set_asn1_flag() sets the asn1_flag on the underlying EC_GROUP object
154(if set). Refer to L<EC_GROUP_copy(3)> for further information on the
155asn1_flag.
156
157EC_KEY_decoded_from_explicit_params() returns 1 if the group of the I<key> was
158decoded from data with explicitly encoded group parameters, -1 if the I<key>
159is NULL or the group parameters are missing, and 0 otherwise.
160
161EC_KEY_precompute_mult() stores multiples of the underlying EC_GROUP generator
162for faster point multiplication. See also L<EC_POINT_add(3)>.
163Modern versions should instead switch to named curves which OpenSSL has
164hardcoded lookup tables for.
165
166EC_KEY_oct2key() and EC_KEY_key2buf() are identical to the functions
167EC_POINT_oct2point() and EC_POINT_point2buf() except they use the public key
168EC_POINT in I<eckey>.
169
170EC_KEY_oct2priv() and EC_KEY_priv2oct() convert between the private key
171component of I<eckey> and octet form. The octet form consists of the content
172octets of the I<privateKey> OCTET STRING in an I<ECPrivateKey> ASN.1 structure.
173
174The function EC_KEY_priv2oct() must be supplied with a buffer long enough to
175store the octet form. The return value provides the number of octets stored.
176Calling the function with a NULL buffer will not perform the conversion but
177will just return the required buffer length.
178
179The function EC_KEY_priv2buf() allocates a buffer of suitable length and writes
180an EC_KEY to it in octet format. The allocated buffer is written to I<*pbuf>
181and its length is returned. The caller must free up the allocated buffer with a
182call to OPENSSL_free(). Since the allocated buffer value is written to I<*pbuf>
183the I<pbuf> parameter B<MUST NOT> be B<NULL>.
184
185EC_KEY_priv2buf() converts an EC_KEY private key into an allocated buffer.
186
187=head1 RETURN VALUES
188
189EC_KEY_new_ex(), EC_KEY_new(), EC_KEY_new_by_curve_name_ex(),
190EC_KEY_new_by_curve_name() and EC_KEY_dup() return a pointer to the newly
191created EC_KEY object, or NULL on error.
192
193EC_KEY_get_flags() returns the flags associated with the EC_KEY object as an
194integer.
195
196EC_KEY_copy() returns a pointer to the destination key, or NULL on error.
197
198EC_KEY_get0_engine() returns a pointer to an ENGINE, or NULL if it wasn't set.
199
200EC_KEY_up_ref(), EC_KEY_set_group(), EC_KEY_set_private_key(),
201EC_KEY_set_public_key(), EC_KEY_precompute_mult(), EC_KEY_generate_key(),
202EC_KEY_check_key(), EC_KEY_set_public_key_affine_coordinates(),
203EC_KEY_oct2key() and EC_KEY_oct2priv() return 1 on success or 0 on error.
204
205EC_KEY_get0_group() returns the EC_GROUP associated with the EC_KEY.
206
207EC_KEY_get0_private_key() returns the private key associated with the EC_KEY.
208
209EC_KEY_get_conv_form() return the point_conversion_form for the EC_KEY.
210
211EC_KEY_key2buf(), EC_KEY_priv2oct() and EC_KEY_priv2buf() return the length
212of the buffer or 0 on error.
213
214=head1 SEE ALSO
215
216L<EVP_PKEY_Q_keygen(3)>
217L<crypto(7)>, L<EC_GROUP_new(3)>,
218L<EC_GROUP_copy(3)>, L<EC_POINT_new(3)>,
219L<EC_POINT_add(3)>,
220L<EC_GFp_simple_method(3)>,
221L<d2i_ECPKParameters(3)>,
222L<OSSL_LIB_CTX(3)>
223
224=head1 HISTORY
225
226EVP_EC_gen() was added in OpenSSL 3.0.
227All other functions described here were deprecated in OpenSSL 3.0.
228For replacement see L<EVP_PKEY-EC(7)>.
229
230=head1 COPYRIGHT
231
232Copyright 2013-2021 The OpenSSL Project Authors. All Rights Reserved.
233
234Licensed under the Apache License 2.0 (the "License").  You may not use
235this file except in compliance with the License.  You can obtain a copy
236in the file LICENSE in the source distribution or at
237L<https://www.openssl.org/source/license.html>.
238
239=cut
240