=pod =head1 NAME i2d_ECPrivateKey, d2i_ECPrivate_key - Encode and decode functions for saving and reading EC_KEY structures =head1 SYNOPSIS #include <openssl/ec.h> EC_KEY *d2i_ECPrivateKey(EC_KEY **key, const unsigned char **in, long len); int i2d_ECPrivateKey(EC_KEY *key, unsigned char **out); unsigned int EC_KEY_get_enc_flags(const EC_KEY *key); void EC_KEY_set_enc_flags(EC_KEY *eckey, unsigned int flags); =head1 DESCRIPTION The ECPrivateKey encode and decode routines encode and parse an B<EC_KEY> structure into a binary format (ASN.1 DER) and back again. These functions are similar to the d2i_X509() functions, and you should refer to that page for a detailed description (see L<d2i_X509(3)|d2i_X509(3)>). The format of the external representation of the public key written by i2d_ECPrivateKey (such as whether it is stored in a compressed form or not) is described by the point_conversion_form. See L<EC_GROUP_copy(3)|EC_GROUP_copy(3)> for a description of point_conversion_form. When reading a private key encoded without an associated public key (e.g. if EC_PKEY_NO_PUBKEY has been used - see below), then d2i_ECPrivateKey generates the missing public key automatically. Private keys encoded without parameters (e.g. if EC_PKEY_NO_PARAMETERS has been used - see below) cannot be loaded using d2i_ECPrivateKey. The functions EC_KEY_get_enc_flags and EC_KEY_set_enc_flags get and set the value of the encoding flags for the B<key>. There are two encoding flags currently defined - EC_PKEY_NO_PARAMETERS and EC_PKEY_NO_PUBKEY. These flags define the behaviour of how the B<key> is converted into ASN1 in a call to i2d_ECPrivateKey. If EC_PKEY_NO_PARAMETERS is set then the public parameters for the curve are not encoded along with the private key. If EC_PKEY_NO_PUBKEY is set then the public key is not encoded along with the private key. =head1 RETURN VALUES d2i_ECPrivateKey() returns a valid B<EC_KEY> structure or B<NULL> if an error occurs. The error code that can be obtained by L<ERR_get_error(3)|ERR_get_error(3)>. i2d_ECPrivateKey() returns the number of bytes successfully encoded or a negative value if an error occurs. The error code can be obtained by L<ERR_get_error(3)|ERR_get_error(3)>. EC_KEY_get_enc_flags returns the value of the current encoding flags for the EC_KEY. =head1 SEE ALSO L<crypto(3)|crypto(3)>, L<ec(3)|ec(3)>, L<EC_GROUP_new(3)|EC_GROUP_new(3)>, L<EC_GROUP_copy(3)|EC_GROUP_copy(3)>, L<EC_POINT_new(3)|EC_POINT_new(3)>, L<EC_POINT_add(3)|EC_POINT_add(3)>, L<EC_GFp_simple_method(3)|EC_GFp_simple_method(3)>, L<d2i_ECPKParameters(3)|d2i_ECPKParameters(3)>, L<d2i_ECPrivateKey(3)|d2i_ECPrivateKey(3)> =cut