i2d_ECPKParameters(3)

NAME

       d2i_ECPKParameters, i2d_ECPKParameters, d2i_ECPKParameters_bio,
       i2d_ECPKParameters_bio, d2i_ECPKParameters_fp, i2d_ECPKParameters_fp,
       ECPKParameters_print, ECPKParameters_print_fp - Functions for decoding
       and encoding ASN1 representations of elliptic curve entities

SYNOPSIS

        #include <openssl/ec.h>

        EC_GROUP *d2i_ECPKParameters(EC_GROUP **px, const unsigned char **in, long len);
        int i2d_ECPKParameters(const EC_GROUP *x, unsigned char **out);
        #define d2i_ECPKParameters_bio(bp,x) ASN1_d2i_bio_of(EC_GROUP,NULL,d2i_ECPKParameters,bp,x)
        #define i2d_ECPKParameters_bio(bp,x) ASN1_i2d_bio_of_const(EC_GROUP,i2d_ECPKParameters,bp,x)
        #define d2i_ECPKParameters_fp(fp,x) (EC_GROUP *)ASN1_d2i_fp(NULL, \
                       (char *(*)())d2i_ECPKParameters,(fp),(unsigned char **)(x))
        #define i2d_ECPKParameters_fp(fp,x) ASN1_i2d_fp(i2d_ECPKParameters,(fp), \
                       (unsigned char *)(x))
        int     ECPKParameters_print(BIO *bp, const EC_GROUP *x, int off);
        int     ECPKParameters_print_fp(FILE *fp, const EC_GROUP *x, int off);

DESCRIPTION

       The ECPKParameters encode and decode routines encode and parse the pub-
       lic parameters for an EC_GROUP structure, which represents a curve.

       d2i_ECPKParameters() attempts to decode len bytes at *in. If successful
       a pointer to the EC_GROUP structure is returned. If an error occurred
       then NULL is returned. If px is not NULL then the returned structure is
       written to *px. If *px is not NULL then it is assumed that *px contains
       a valid EC_GROUP structure and an attempt is made to reuse it. If the
       call is successful *in is incremented to the byte following the parsed
       data.

       i2d_ECPKParameters() encodes the structure pointed to by x into DER
       format.  If out is not NULL is writes the DER encoded data to the
       buffer at *out, and increments it to point after the data just written.
       If the return value is negative an error occurred, otherwise it returns
       the length of the encoded data.

       If *out is NULL memory will be allocated for a buffer and the encoded
       data written to it. In this case *out is not incremented and it points
       to the start of the data just written.

       d2i_ECPKParameters_bio() is similar to d2i_ECPKParameters() except it
       attempts to parse data from BIO bp.

       d2i_ECPKParameters_fp() is similar to d2i_ECPKParameters() except it
       attempts to parse data from FILE pointer fp.

       i2d_ECPKParameters_bio() is similar to i2d_ECPKParameters() except it
       writes the encoding of the structure x to BIO bp and it returns 1 for
       success and 0 for failure.

       i2d_ECPKParameters_fp() is similar to i2d_ECPKParameters() except it
       writes the encoding of the structure x to BIO bp and it returns 1 for
       success and 0 for failure.

       These functions are very similar to the X509 functions described in
       d2i_X509(3), where further notes and examples are available.

       The ECPKParameters_print and ECPKParameters_print_fp functions print a
       human-readable output of the public parameters of the EC_GROUP to bp or
       fp. The output lines are indented by off spaces.

RETURN VALUES

       d2i_ECPKParameters(), d2i_ECPKParameters_bio() and d2i_ECPKParame-
       ters_fp() return a valid EC_GROUP structure or NULL if an error occurs.

       i2d_ECPKParameters() returns the number of bytes successfully encoded
       or a negative value if an error occurs.

       i2d_ECPKParameters_bio(), i2d_ECPKParameters_fp(), ECPKParameters_print
       and ECPKParameters_print_fp return 1 for success and 0 if an error
       occurs.

SEE ALSO

       crypto(3), ec(3), EC_GROUP_new(3), EC_GROUP_copy(3), EC_POINT_new(3),
       EC_POINT_add(3), EC_KEY_new(3), EC_GFp_simple_method(3), d2i_X509(3)

1.0.2t                            2019-09-10             d2i_ECPKParameters(3)