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Diffstat (limited to 'openssl-1.1.0h/doc/crypto/EC_POINT_new.pod')
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diff --git a/openssl-1.1.0h/doc/crypto/EC_POINT_new.pod b/openssl-1.1.0h/doc/crypto/EC_POINT_new.pod new file mode 100644 index 0000000..5ac41b3 --- /dev/null +++ b/openssl-1.1.0h/doc/crypto/EC_POINT_new.pod @@ -0,0 +1,196 @@ +=pod + +=head1 NAME + +EC_POINT_set_Jprojective_coordinates_GFp, EC_POINT_point2buf, +EC_POINT_new, EC_POINT_free, EC_POINT_clear_free, +EC_POINT_copy, EC_POINT_dup, EC_POINT_method_of, +EC_POINT_set_to_infinity, +EC_POINT_get_Jprojective_coordinates_GFp, +EC_POINT_set_affine_coordinates_GFp, +EC_POINT_get_affine_coordinates_GFp, EC_POINT_set_compressed_coordinates_GFp, +EC_POINT_set_affine_coordinates_GF2m, EC_POINT_get_affine_coordinates_GF2m, +EC_POINT_set_compressed_coordinates_GF2m, EC_POINT_point2oct, +EC_POINT_oct2point, EC_POINT_point2bn, EC_POINT_bn2point, EC_POINT_point2hex, +EC_POINT_hex2point +- Functions for creating, destroying and manipulating EC_POINT objects + +=head1 SYNOPSIS + + #include <openssl/ec.h> + + EC_POINT *EC_POINT_new(const EC_GROUP *group); + void EC_POINT_free(EC_POINT *point); + void EC_POINT_clear_free(EC_POINT *point); + int EC_POINT_copy(EC_POINT *dst, const EC_POINT *src); + EC_POINT *EC_POINT_dup(const EC_POINT *src, const EC_GROUP *group); + const EC_METHOD *EC_POINT_method_of(const EC_POINT *point); + int EC_POINT_set_to_infinity(const EC_GROUP *group, EC_POINT *point); + int EC_POINT_set_Jprojective_coordinates_GFp(const EC_GROUP *group, + EC_POINT *p, + const BIGNUM *x, const BIGNUM *y, + const BIGNUM *z, BN_CTX *ctx); + int EC_POINT_get_Jprojective_coordinates_GFp(const EC_GROUP *group, + const EC_POINT *p, + BIGNUM *x, BIGNUM *y, BIGNUM *z, + BN_CTX *ctx); + int EC_POINT_set_affine_coordinates_GFp(const EC_GROUP *group, EC_POINT *p, + const BIGNUM *x, const BIGNUM *y, + BN_CTX *ctx); + int EC_POINT_get_affine_coordinates_GFp(const EC_GROUP *group, + const EC_POINT *p, + BIGNUM *x, BIGNUM *y, BN_CTX *ctx); + int EC_POINT_set_compressed_coordinates_GFp(const EC_GROUP *group, + EC_POINT *p, + const BIGNUM *x, int y_bit, + BN_CTX *ctx); + int EC_POINT_set_affine_coordinates_GF2m(const EC_GROUP *group, EC_POINT *p, + const BIGNUM *x, const BIGNUM *y, + BN_CTX *ctx); + int EC_POINT_get_affine_coordinates_GF2m(const EC_GROUP *group, + const EC_POINT *p, + BIGNUM *x, BIGNUM *y, BN_CTX *ctx); + int EC_POINT_set_compressed_coordinates_GF2m(const EC_GROUP *group, + EC_POINT *p, + const BIGNUM *x, int y_bit, + BN_CTX *ctx); + size_t EC_POINT_point2oct(const EC_GROUP *group, const EC_POINT *p, + point_conversion_form_t form, + unsigned char *buf, size_t len, BN_CTX *ctx); + size_t EC_POINT_point2buf(const EC_GROUP *group, const EC_POINT *point, + point_conversion_form_t form, + unsigned char **pbuf, BN_CTX *ctx); + int EC_POINT_oct2point(const EC_GROUP *group, EC_POINT *p, + const unsigned char *buf, size_t len, BN_CTX *ctx); + BIGNUM *EC_POINT_point2bn(const EC_GROUP *group, const EC_POINT *p, + point_conversion_form_t form, BIGNUM *bn, + BN_CTX *ctx); + EC_POINT *EC_POINT_bn2point(const EC_GROUP *group, const BIGNUM *bn, + EC_POINT *p, BN_CTX *ctx); + char *EC_POINT_point2hex(const EC_GROUP *group, const EC_POINT *p, + point_conversion_form_t form, BN_CTX *ctx); + EC_POINT *EC_POINT_hex2point(const EC_GROUP *group, const char *hex, + EC_POINT *p, BN_CTX *ctx); + + +=head1 DESCRIPTION + +An B<EC_POINT> structure represents a point on a curve. A new point is +constructed by calling the function EC_POINT_new() and providing the +B<group> object that the point relates to. + +EC_POINT_free() frees the memory associated with the B<EC_POINT>. +if B<point> is NULL nothing is done. + +EC_POINT_clear_free() destroys any sensitive data held within the EC_POINT and +then frees its memory. If B<point> is NULL nothing is done. + +EC_POINT_copy() copies the point B<src> into B<dst>. Both B<src> and B<dst> +must use the same B<EC_METHOD>. + +EC_POINT_dup() creates a new B<EC_POINT> object and copies the content from +B<src> to the newly created B<EC_POINT> object. + +EC_POINT_method_of() obtains the B<EC_METHOD> associated with B<point>. + +A valid point on a curve is the special point at infinity. A point is set to +be at infinity by calling EC_POINT_set_to_infinity(). + +The affine co-ordinates for a point describe a point in terms of its x and y +position. The functions EC_POINT_set_affine_coordinates_GFp() and +EC_POINT_set_affine_coordinates_GF2m() set the B<x> and B<y> co-ordinates for +the point B<p> defined over the curve given in B<group>. + +As well as the affine co-ordinates, a point can alternatively be described in +terms of its Jacobian projective co-ordinates (for Fp curves only). Jacobian +projective co-ordinates are expressed as three values x, y and z. Working in +this co-ordinate system provides more efficient point multiplication +operations. A mapping exists between Jacobian projective co-ordinates and +affine co-ordinates. A Jacobian projective co-ordinate (x, y, z) can be written +as an affine co-ordinate as (x/(z^2), y/(z^3)). Conversion to Jacobian +projective from affine co-ordinates is simple. The co-ordinate (x, y) is mapped +to (x, y, 1). To set or get the projective co-ordinates use +EC_POINT_set_Jprojective_coordinates_GFp() and +EC_POINT_get_Jprojective_coordinates_GFp() respectively. + +Points can also be described in terms of their compressed co-ordinates. For a +point (x, y), for any given value for x such that the point is on the curve +there will only ever be two possible values for y. Therefore a point can be set +using the EC_POINT_set_compressed_coordinates_GFp() and +EC_POINT_set_compressed_coordinates_GF2m() functions where B<x> is the x +co-ordinate and B<y_bit> is a value 0 or 1 to identify which of the two +possible values for y should be used. + +In addition B<EC_POINT> can be converted to and from various external +representations. The octet form is the binary encoding of the B<ECPoint> +structure (as defined in RFC5480 and used in certificates and TLS records): +only the content octets are present, the B<OCTET STRING> tag and length are +not included. B<BIGNUM> form is the octet form interpreted as a big endian +integer converted to a B<BIGNUM> structure. Hexadecimal form is the octet +form converted to a NULL terminated character string where each character +is one of the printable values 0-9 or A-F (or a-f). + +The functions EC_POINT_point2oct(), EC_POINT_oct2point(), EC_POINT_point2bn(), +EC_POINT_bn2point(), EC_POINT_point2hex() and EC_POINT_hex2point() convert from +and to EC_POINTs for the formats: octet, BIGNUM and hexadecimal respectively. + +The function EC_POINT_point2oct() must be supplied with a buffer long enough to +store the octet form. The return value provides the number of octets stored. +Calling the function with a NULL buffer will not perform the conversion but +will still return the required buffer length. + +The function EC_POINT_point2buf() allocates a buffer of suitable length and +writes an EC_POINT to it in octet format. The allocated buffer is written to +B<*pbuf> and its length is returned. The caller must free up the allocated +buffer with a call to OPENSSL_free(). Since the allocated buffer value is +written to B<*pbuf> the B<pbuf> parameter B<MUST NOT> be B<NULL>. + +The function EC_POINT_point2hex() will allocate sufficient memory to store the +hexadecimal string. It is the caller's responsibility to free this memory with +a subsequent call to OPENSSL_free(). + +=head1 RETURN VALUES + +EC_POINT_new() and EC_POINT_dup() return the newly allocated EC_POINT or NULL +on error. + +The following functions return 1 on success or 0 on error: EC_POINT_copy(), +EC_POINT_set_to_infinity(), EC_POINT_set_Jprojective_coordinates_GFp(), +EC_POINT_get_Jprojective_coordinates_GFp(), +EC_POINT_set_affine_coordinates_GFp(), EC_POINT_get_affine_coordinates_GFp(), +EC_POINT_set_compressed_coordinates_GFp(), +EC_POINT_set_affine_coordinates_GF2m(), EC_POINT_get_affine_coordinates_GF2m(), +EC_POINT_set_compressed_coordinates_GF2m() and EC_POINT_oct2point(). + +EC_POINT_method_of returns the EC_METHOD associated with the supplied EC_POINT. + +EC_POINT_point2oct() and EC_POINT_point2buf() return the length of the required +buffer or 0 on error. + +EC_POINT_point2bn() returns the pointer to the BIGNUM supplied, or NULL on +error. + +EC_POINT_bn2point() returns the pointer to the EC_POINT supplied, or NULL on +error. + +EC_POINT_point2hex() returns a pointer to the hex string, or NULL on error. + +EC_POINT_hex2point() returns the pointer to the EC_POINT supplied, or NULL on +error. + +=head1 SEE ALSO + +L<crypto(7)>, L<EC_GROUP_new(3)>, L<EC_GROUP_copy(3)>, +L<EC_POINT_add(3)>, L<EC_KEY_new(3)>, +L<EC_GFp_simple_method(3)>, L<d2i_ECPKParameters(3)> + +=head1 COPYRIGHT + +Copyright 2013-2018 The OpenSSL Project Authors. All Rights Reserved. + +Licensed under the OpenSSL license (the "License"). You may not use +this file except in compliance with the License. You can obtain a copy +in the file LICENSE in the source distribution or at +L<https://www.openssl.org/source/license.html>. + +=cut |