d2i_ECPrivateKey.pod revision 296341 
1=pod
2
3=head1 NAME
4
5i2d_ECPrivateKey, d2i_ECPrivate_key - Encode and decode functions for saving and
6reading EC_KEY structures
7
8=head1 SYNOPSIS
9
10 #include <openssl/ec.h>
11
12 EC_KEY *d2i_ECPrivateKey(EC_KEY **key, const unsigned char **in, long len);
13 int i2d_ECPrivateKey(EC_KEY *key, unsigned char **out);
14
15 unsigned int EC_KEY_get_enc_flags(const EC_KEY *key);
16 void EC_KEY_set_enc_flags(EC_KEY *eckey, unsigned int flags);
17
18=head1 DESCRIPTION
19
20The ECPrivateKey encode and decode routines encode and parse an
21B<EC_KEY> structure into a binary format (ASN.1 DER) and back again.
22
23These functions are similar to the d2i_X509() functions, and you should refer to
24that page for a detailed description (see L<d2i_X509(3)|d2i_X509(3)>).
25
26The format of the external representation of the public key written by
27i2d_ECPrivateKey (such as whether it is stored in a compressed form or not) is
28described by the point_conversion_form. See L<EC_GROUP_copy(3)|EC_GROUP_copy(3)>
29for a description of point_conversion_form.
30
31When reading a private key encoded without an associated public key (e.g. if
32EC_PKEY_NO_PUBKEY has been used - see below), then d2i_ECPrivateKey generates
33the missing public key automatically. Private keys encoded without parameters
34(e.g. if EC_PKEY_NO_PARAMETERS has been used - see below) cannot be loaded using
35d2i_ECPrivateKey.
36
37The functions EC_KEY_get_enc_flags and EC_KEY_set_enc_flags get and set the
38value of the encoding flags for the B<key>. There are two encoding flags
39currently defined - EC_PKEY_NO_PARAMETERS and EC_PKEY_NO_PUBKEY.  These flags
40define the behaviour of how the  B<key> is converted into ASN1 in a call to
41i2d_ECPrivateKey. If EC_PKEY_NO_PARAMETERS is set then the public parameters for
42the curve are not encoded along with the private key. If EC_PKEY_NO_PUBKEY is
43set then the public key is not encoded along with the private key.
44
45=head1 RETURN VALUES
46
47d2i_ECPrivateKey() returns a valid B<EC_KEY> structure or B<NULL> if an error
48occurs. The error code that can be obtained by
49L<ERR_get_error(3)|ERR_get_error(3)>.
50
51i2d_ECPrivateKey() returns the number of bytes successfully encoded or a
52negative value if an error occurs. The error code can be obtained by
53L<ERR_get_error(3)|ERR_get_error(3)>.
54
55EC_KEY_get_enc_flags returns the value of the current encoding flags for the
56EC_KEY.
57
58=head1 SEE ALSO
59
60L<crypto(3)|crypto(3)>, L<ec(3)|ec(3)>, L<EC_GROUP_new(3)|EC_GROUP_new(3)>,
61L<EC_GROUP_copy(3)|EC_GROUP_copy(3)>, L<EC_POINT_new(3)|EC_POINT_new(3)>,
62L<EC_POINT_add(3)|EC_POINT_add(3)>,
63L<EC_GFp_simple_method(3)|EC_GFp_simple_method(3)>,
64L<d2i_ECPKParameters(3)|d2i_ECPKParameters(3)>,
65L<d2i_ECPrivateKey(3)|d2i_ECPrivateKey(3)>
66
67=cut
68