NAME

       i2d_ECPrivateKey, d2i_ECPrivate_key - Encode and decode functions for saving and reading EC_KEY
       structures

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);

DESCRIPTION

       The ECPrivateKey encode and decode routines encode and parse an 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 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 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 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  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.

RETURN VALUES

       d2i_ECPrivateKey() returns a valid EC_KEY structure or NULL if an error occurs. The error code that can
       be obtained by 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 ERR_get_error(3).

       EC_KEY_get_enc_flags returns the value of the current encoding flags for the EC_KEY.

SEE ALSO

       crypto(3), ec(3), EC_GROUP_new(3), EC_GROUP_copy(3), EC_POINT_new(3), EC_POINT_add(3),
       EC_GFp_simple_method(3), d2i_ECPKParameters(3), d2i_ECPrivateKey(3)