1=pod 2 3=head1 NAME 4 5d2i_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 6 7=head1 SYNOPSIS 8 9 #include <openssl/ec.h> 10 11 EC_GROUP *d2i_ECPKParameters(EC_GROUP **px, const unsigned char **in, long len); 12 int i2d_ECPKParameters(const EC_GROUP *x, unsigned char **out); 13 #define d2i_ECPKParameters_bio(bp,x) ASN1_d2i_bio_of(EC_GROUP,NULL,d2i_ECPKParameters,bp,x) 14 #define i2d_ECPKParameters_bio(bp,x) ASN1_i2d_bio_of_const(EC_GROUP,i2d_ECPKParameters,bp,x) 15 #define d2i_ECPKParameters_fp(fp,x) (EC_GROUP *)ASN1_d2i_fp(NULL, \ 16 (char *(*)())d2i_ECPKParameters,(fp),(unsigned char **)(x)) 17 #define i2d_ECPKParameters_fp(fp,x) ASN1_i2d_fp(i2d_ECPKParameters,(fp), \ 18 (unsigned char *)(x)) 19 int ECPKParameters_print(BIO *bp, const EC_GROUP *x, int off); 20 int ECPKParameters_print_fp(FILE *fp, const EC_GROUP *x, int off); 21 22 23=head1 DESCRIPTION 24 25The ECPKParameters encode and decode routines encode and parse the public parameters for an 26B<EC_GROUP> structure, which represents a curve. 27 28d2i_ECPKParameters() attempts to decode B<len> bytes at B<*in>. If 29successful a pointer to the B<EC_GROUP> structure is returned. If an error 30occurred then B<NULL> is returned. If B<px> is not B<NULL> then the 31returned structure is written to B<*px>. If B<*px> is not B<NULL> 32then it is assumed that B<*px> contains a valid B<EC_GROUP> 33structure and an attempt is made to reuse it. If the call is 34successful B<*in> is incremented to the byte following the 35parsed data. 36 37i2d_ECPKParameters() encodes the structure pointed to by B<x> into DER format. 38If B<out> is not B<NULL> is writes the DER encoded data to the buffer 39at B<*out>, and increments it to point after the data just written. 40If the return value is negative an error occurred, otherwise it 41returns the length of the encoded data. 42 43If B<*out> is B<NULL> memory will be allocated for a buffer and the encoded 44data written to it. In this case B<*out> is not incremented and it points to 45the start of the data just written. 46 47d2i_ECPKParameters_bio() is similar to d2i_ECPKParameters() except it attempts 48to parse data from BIO B<bp>. 49 50d2i_ECPKParameters_fp() is similar to d2i_ECPKParameters() except it attempts 51to parse data from FILE pointer B<fp>. 52 53i2d_ECPKParameters_bio() is similar to i2d_ECPKParameters() except it writes 54the encoding of the structure B<x> to BIO B<bp> and it 55returns 1 for success and 0 for failure. 56 57i2d_ECPKParameters_fp() is similar to i2d_ECPKParameters() except it writes 58the encoding of the structure B<x> to BIO B<bp> and it 59returns 1 for success and 0 for failure. 60 61These functions are very similar to the X509 functions described in L<d2i_X509(3)|d2i_X509(3)>, 62where further notes and examples are available. 63 64The ECPKParameters_print and ECPKParameters_print_fp functions print a human-readable output 65of the public parameters of the EC_GROUP to B<bp> or B<fp>. The output lines are indented by B<off> spaces. 66 67=head1 RETURN VALUES 68 69d2i_ECPKParameters(), d2i_ECPKParameters_bio() and d2i_ECPKParameters_fp() return a valid B<EC_GROUP> structure 70or B<NULL> if an error occurs. 71 72i2d_ECPKParameters() returns the number of bytes successfully encoded or a negative 73value if an error occurs. 74 75i2d_ECPKParameters_bio(), i2d_ECPKParameters_fp(), ECPKParameters_print and ECPKParameters_print_fp 76return 1 for success and 0 if an error occurs. 77 78=head1 SEE ALSO 79 80L<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)>, 81L<EC_POINT_new(3)|EC_POINT_new(3)>, L<EC_POINT_add(3)|EC_POINT_add(3)>, L<EC_KEY_new(3)|EC_KEY_new(3)>, 82L<EC_GFp_simple_method(3)|EC_GFp_simple_method(3)>, L<d2i_X509(3)|d2i_X509(3)> 83 84=cut 85