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Diffstat (limited to 'secure/lib/libcrypto/man/EC_GROUP_new.3')
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diff --git a/secure/lib/libcrypto/man/EC_GROUP_new.3 b/secure/lib/libcrypto/man/EC_GROUP_new.3 new file mode 100644 index 0000000..8f95b25 --- /dev/null +++ b/secure/lib/libcrypto/man/EC_GROUP_new.3 @@ -0,0 +1,230 @@ +.\" Automatically generated by Pod::Man 2.28 (Pod::Simple 3.30) +.\" +.\" Standard preamble: +.\" ======================================================================== +.de Sp \" Vertical space (when we can't use .PP) +.if t .sp .5v +.if n .sp +.. +.de Vb \" Begin verbatim text +.ft CW +.nf +.ne \\$1 +.. +.de Ve \" End verbatim text +.ft R +.fi +.. +.\" Set up some character translations and predefined strings. \*(-- will +.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left +.\" double quote, and \*(R" will give a right double quote. \*(C+ will +.\" give a nicer C++. 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Always turn off hyphenation; it makes +.\" way too many mistakes in technical documents. +.if n .ad l +.nh +.SH "NAME" +EC_GROUP_new, EC_GROUP_free, EC_GROUP_clear_free, EC_GROUP_new_curve_GFp, EC_GROUP_new_curve_GF2m, EC_GROUP_new_by_curve_name, EC_GROUP_set_curve_GFp, EC_GROUP_get_curve_GFp, EC_GROUP_set_curve_GF2m, EC_GROUP_get_curve_GF2m, EC_get_builtin_curves \- Functions for creating and destroying EC_GROUP objects. +.SH "SYNOPSIS" +.IX Header "SYNOPSIS" +.Vb 2 +\& #include <openssl/ec.h> +\& #include <openssl/bn.h> +\& +\& EC_GROUP *EC_GROUP_new(const EC_METHOD *meth); +\& void EC_GROUP_free(EC_GROUP *group); +\& void EC_GROUP_clear_free(EC_GROUP *group); +\& +\& EC_GROUP *EC_GROUP_new_curve_GFp(const BIGNUM *p, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx); +\& EC_GROUP *EC_GROUP_new_curve_GF2m(const BIGNUM *p, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx); +\& EC_GROUP *EC_GROUP_new_by_curve_name(int nid); +\& +\& int EC_GROUP_set_curve_GFp(EC_GROUP *group, const BIGNUM *p, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx); +\& int EC_GROUP_get_curve_GFp(const EC_GROUP *group, BIGNUM *p, BIGNUM *a, BIGNUM *b, BN_CTX *ctx); +\& int EC_GROUP_set_curve_GF2m(EC_GROUP *group, const BIGNUM *p, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx); +\& int EC_GROUP_get_curve_GF2m(const EC_GROUP *group, BIGNUM *p, BIGNUM *a, BIGNUM *b, BN_CTX *ctx); +\& +\& size_t EC_get_builtin_curves(EC_builtin_curve *r, size_t nitems); +.Ve +.SH "DESCRIPTION" +.IX Header "DESCRIPTION" +Within the library there are two forms of elliptic curve that are of interest. The first form is those defined over the +prime field Fp. The elements of Fp are the integers 0 to p\-1, where p is a prime number. This gives us a revised +elliptic curve equation as follows: +.PP +y^2 mod p = x^3 +ax + b mod p +.PP +The second form is those defined over a binary field F2^m where the elements of the field are integers of length at +most m bits. For this form the elliptic curve equation is modified to: +.PP +y^2 + xy = x^3 + ax^2 + b (where b != 0) +.PP +Operations in a binary field are performed relative to an \fBirreducible polynomial\fR. All such curves with OpenSSL +use a trinomial or a pentanomial for this parameter. +.PP +A new curve can be constructed by calling EC_GROUP_new, using the implementation provided by \fBmeth\fR (see +\&\fIEC_GFp_simple_method\fR\|(3)). It is then necessary to call either EC_GROUP_set_curve_GFp or +EC_GROUP_set_curve_GF2m as appropriate to create a curve defined over Fp or over F2^m respectively. +.PP +EC_GROUP_set_curve_GFp sets the curve parameters \fBp\fR, \fBa\fR and \fBb\fR for a curve over Fp stored in \fBgroup\fR. +EC_group_get_curve_GFp obtains the previously set curve parameters. +.PP +EC_GROUP_set_curve_GF2m sets the equivalent curve parameters for a curve over F2^m. In this case \fBp\fR represents +the irreducible polybnomial \- each bit represents a term in the polynomial. Therefore there will either be three +or five bits set dependant on whether the polynomial is a trinomial or a pentanomial. +EC_group_get_curve_GF2m obtains the previously set curve parameters. +.PP +The functions EC_GROUP_new_curve_GFp and EC_GROUP_new_curve_GF2m are shortcuts for calling EC_GROUP_new and the +appropriate EC_group_set_curve function. An appropriate default implementation method will be used. +.PP +Whilst the library can be used to create any curve using the functions described above, there are also a number of +predefined curves that are available. In order to obtain a list of all of the predefined curves, call the function +EC_get_builtin_curves. The parameter \fBr\fR should be an array of EC_builtin_curve structures of size \fBnitems\fR. The function +will populate the \fBr\fR array with information about the builtin curves. If \fBnitems\fR is less than the total number of +curves available, then the first \fBnitems\fR curves will be returned. Otherwise the total number of curves will be +provided. The return value is the total number of curves available (whether that number has been populated in \fBr\fR or +not). Passing a \s-1NULL \s0\fBr\fR, or setting \fBnitems\fR to 0 will do nothing other than return the total number of curves available. +The EC_builtin_curve structure is defined as follows: +.PP +.Vb 4 +\& typedef struct { +\& int nid; +\& const char *comment; +\& } EC_builtin_curve; +.Ve +.PP +Each EC_builtin_curve item has a unique integer id (\fBnid\fR), and a human readable comment string describing the curve. +.PP +In order to construct a builtin curve use the function EC_GROUP_new_by_curve_name and provide the \fBnid\fR of the curve to +be constructed. +.PP +EC_GROUP_free frees the memory associated with the \s-1EC_GROUP.\s0 +.PP +EC_GROUP_clear_free destroys any sensitive data held within the \s-1EC_GROUP\s0 and then frees its memory. +.SH "RETURN VALUES" +.IX Header "RETURN VALUES" +All EC_GROUP_new* functions return a pointer to the newly constructed group, or \s-1NULL\s0 on error. +.PP +EC_get_builtin_curves returns the number of builtin curves that are available. +.PP +EC_GROUP_set_curve_GFp, EC_GROUP_get_curve_GFp, EC_GROUP_set_curve_GF2m, EC_GROUP_get_curve_GF2m return 1 on success or 0 on error. +.SH "SEE ALSO" +.IX Header "SEE ALSO" +\&\fIcrypto\fR\|(3), \fIec\fR\|(3), \fIEC_GROUP_copy\fR\|(3), +\&\fIEC_POINT_new\fR\|(3), \fIEC_POINT_add\fR\|(3), \fIEC_KEY_new\fR\|(3), +\&\fIEC_GFp_simple_method\fR\|(3), \fId2i_ECPKParameters\fR\|(3) |
