D7net
Home
Console
Upload
information
Create File
Create Folder
About
Tools
:
/
opt
/
lampp
/
share
/
openssl
/
man
/
man3
/
Filename :
EC_GROUP_get0_seed.3
back
Copy
.\" Automatically generated by Pod::Man v1.37, Pod::Parser v1.32 .\" .\" Standard preamble: .\" ======================================================================== .de Sh \" Subsection heading .br .if t .Sp .ne 5 .PP \fB\\$1\fR .PP .. .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. | will give a .\" real vertical bar. \*(C+ will give a nicer C++. Capital omega is used to .\" do unbreakable dashes and therefore won't be available. \*(C` and \*(C' .\" expand to `' in nroff, nothing in troff, for use with C<>. .tr \(*W-|\(bv\*(Tr .ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p' .ie n \{\ . ds -- \(*W- . ds PI pi . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch . ds L" "" . ds R" "" . ds C` "" . ds C' "" 'br\} .el\{\ . ds -- \|\(em\| . ds PI \(*p . ds L" `` . ds R" '' 'br\} .\" .\" If the F register is turned on, we'll generate index entries on stderr for .\" titles (.TH), headers (.SH), subsections (.Sh), items (.Ip), and index .\" entries marked with X<> in POD. Of course, you'll have to process the .\" output yourself in some meaningful fashion. .if \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . nr % 0 . rr F .\} .\" .\" For nroff, turn off justification. Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .hy 0 .if n .na .\" .\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2). .\" Fear. Run. Save yourself. No user-serviceable parts. . \" fudge factors for nroff and troff .if n \{\ . ds #H 0 . ds #V .8m . ds #F .3m . ds #[ \f1 . ds #] \fP .\} .if t \{\ . ds #H ((1u-(\\\\n(.fu%2u))*.13m) . ds #V .6m . ds #F 0 . ds #[ \& . ds #] \& .\} . \" simple accents for nroff and troff .if n \{\ . ds ' \& . ds ` \& . ds ^ \& . ds , \& . ds ~ ~ . ds / .\} .if t \{\ . ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u" . ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u' . ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u' . ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u' . ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u' . ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u' .\} . \" troff and (daisy-wheel) nroff accents .ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V' .ds 8 \h'\*(#H'\(*b\h'-\*(#H' .ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#] .ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H' .ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u' .ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#] .ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#] .ds ae a\h'-(\w'a'u*4/10)'e .ds Ae A\h'-(\w'A'u*4/10)'E . \" corrections for vroff .if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u' .if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u' . \" for low resolution devices (crt and lpr) .if \n(.H>23 .if \n(.V>19 \ \{\ . ds : e . ds 8 ss . ds o a . ds d- d\h'-1'\(ga . ds D- D\h'-1'\(hy . ds th \o'bp' . ds Th \o'LP' . ds ae ae . ds Ae AE .\} .rm #[ #] #H #V #F C .\" ======================================================================== .\" .IX Title "EC_GROUP_copy 3" .TH EC_GROUP_copy 3 "2017-05-25" "1.0.2l" "OpenSSL" .SH "NAME" EC_GROUP_copy, EC_GROUP_dup, EC_GROUP_method_of, EC_GROUP_set_generator, EC_GROUP_get0_generator, EC_GROUP_get_order, EC_GROUP_get_cofactor, EC_GROUP_set_curve_name, EC_GROUP_get_curve_name, EC_GROUP_set_asn1_flag, EC_GROUP_get_asn1_flag, EC_GROUP_set_point_conversion_form, EC_GROUP_get_point_conversion_form, EC_GROUP_get0_seed, EC_GROUP_get_seed_len, EC_GROUP_set_seed, EC_GROUP_get_degree, EC_GROUP_check, EC_GROUP_check_discriminant, EC_GROUP_cmp, EC_GROUP_get_basis_type, EC_GROUP_get_trinomial_basis, EC_GROUP_get_pentanomial_basis \- Functions for manipulating \fBEC_GROUP\fR objects. .SH "SYNOPSIS" .IX Header "SYNOPSIS" .Vb 2 \& #include <openssl/ec.h> \& #include <openssl/bn.h> .Ve .PP .Vb 2 \& int EC_GROUP_copy(EC_GROUP *dst, const EC_GROUP *src); \& EC_GROUP *EC_GROUP_dup(const EC_GROUP *src); .Ve .PP .Vb 1 \& const EC_METHOD *EC_GROUP_method_of(const EC_GROUP *group); .Ve .PP .Vb 2 \& int EC_GROUP_set_generator(EC_GROUP *group, const EC_POINT *generator, const BIGNUM *order, const BIGNUM *cofactor); \& const EC_POINT *EC_GROUP_get0_generator(const EC_GROUP *group); .Ve .PP .Vb 2 \& int EC_GROUP_get_order(const EC_GROUP *group, BIGNUM *order, BN_CTX *ctx); \& int EC_GROUP_get_cofactor(const EC_GROUP *group, BIGNUM *cofactor, BN_CTX *ctx); .Ve .PP .Vb 2 \& void EC_GROUP_set_curve_name(EC_GROUP *group, int nid); \& int EC_GROUP_get_curve_name(const EC_GROUP *group); .Ve .PP .Vb 2 \& void EC_GROUP_set_asn1_flag(EC_GROUP *group, int flag); \& int EC_GROUP_get_asn1_flag(const EC_GROUP *group); .Ve .PP .Vb 2 \& void EC_GROUP_set_point_conversion_form(EC_GROUP *group, point_conversion_form_t form); \& point_conversion_form_t EC_GROUP_get_point_conversion_form(const EC_GROUP *); .Ve .PP .Vb 3 \& unsigned char *EC_GROUP_get0_seed(const EC_GROUP *x); \& size_t EC_GROUP_get_seed_len(const EC_GROUP *); \& size_t EC_GROUP_set_seed(EC_GROUP *, const unsigned char *, size_t len); .Ve .PP .Vb 1 \& int EC_GROUP_get_degree(const EC_GROUP *group); .Ve .PP .Vb 1 \& int EC_GROUP_check(const EC_GROUP *group, BN_CTX *ctx); .Ve .PP .Vb 1 \& int EC_GROUP_check_discriminant(const EC_GROUP *group, BN_CTX *ctx); .Ve .PP .Vb 1 \& int EC_GROUP_cmp(const EC_GROUP *a, const EC_GROUP *b, BN_CTX *ctx); .Ve .PP .Vb 4 \& int EC_GROUP_get_basis_type(const EC_GROUP *); \& int EC_GROUP_get_trinomial_basis(const EC_GROUP *, unsigned int *k); \& int EC_GROUP_get_pentanomial_basis(const EC_GROUP *, unsigned int *k1, \& unsigned int *k2, unsigned int *k3); .Ve .SH "DESCRIPTION" .IX Header "DESCRIPTION" EC_GROUP_copy copies the curve \fBsrc\fR into \fBdst\fR. Both \fBsrc\fR and \fBdst\fR must use the same \s-1EC_METHOD\s0. .PP EC_GROUP_dup creates a new \s-1EC_GROUP\s0 object and copies the content from \fBsrc\fR to the newly created \&\s-1EC_GROUP\s0 object. .PP EC_GROUP_method_of obtains the \s-1EC_METHOD\s0 of \fBgroup\fR. .PP EC_GROUP_set_generator sets curve paramaters that must be agreed by all participants using the curve. These paramaters include the \fBgenerator\fR, the \fBorder\fR and the \fBcofactor\fR. The \fBgenerator\fR is a well defined point on the curve chosen for cryptographic operations. Integers used for point multiplications will be between 0 and n\-1 where n is the \fBorder\fR. The \fBorder\fR multipied by the \fBcofactor\fR gives the number of points on the curve. .PP EC_GROUP_get0_generator returns the generator for the identified \fBgroup\fR. .PP The functions EC_GROUP_get_order and EC_GROUP_get_cofactor populate the provided \fBorder\fR and \fBcofactor\fR parameters with the respective order and cofactors for the \fBgroup\fR. .PP The functions EC_GROUP_set_curve_name and EC_GROUP_get_curve_name, set and get the \s-1NID\s0 for the curve respectively (see \fIEC_GROUP_new\fR\|(3)). If a curve does not have a \s-1NID\s0 associated with it, then EC_GROUP_get_curve_name will return 0. .PP The asn1_flag value on a curve is used to determine whether there is a specific \s-1ASN1\s0 \s-1OID\s0 to describe the curve or not. If the asn1_flag is 1 then this is a named curve with an associated \s-1ASN1\s0 \s-1OID\s0. If not then asn1_flag is 0. The functions EC_GROUP_get_asn1_flag and EC_GROUP_set_asn1_flag get and set the status of the asn1_flag for the curve. If set then the curve_name must also be set. .PP The point_coversion_form for a curve controls how \s-1EC_POINT\s0 data is encoded as \s-1ASN1\s0 as defined in X9.62 (\s-1ECDSA\s0). point_conversion_form_t is an enum defined as follows: .PP .Vb 10 \& typedef enum { \& /** the point is encoded as z||x, where the octet z specifies \& * which solution of the quadratic equation y is */ \& POINT_CONVERSION_COMPRESSED = 2, \& /** the point is encoded as z||x||y, where z is the octet 0x02 */ \& POINT_CONVERSION_UNCOMPRESSED = 4, \& /** the point is encoded as z||x||y, where the octet z specifies \& * which solution of the quadratic equation y is */ \& POINT_CONVERSION_HYBRID = 6 \& } point_conversion_form_t; .Ve .PP For \s-1POINT_CONVERSION_UNCOMPRESSED\s0 the point is encoded as an octet signifying the \s-1UNCOMPRESSED\s0 form has been used followed by the octets for x, followed by the octets for y. .PP For any given x co-ordinate for a point on a curve it is possible to derive two possible y values. For \&\s-1POINT_CONVERSION_COMPRESSED\s0 the point is encoded as an octet signifying that the \s-1COMPRESSED\s0 form has been used \s-1AND\s0 which of the two possible solutions for y has been used, followed by the octets for x. .PP For \s-1POINT_CONVERSION_HYBRID\s0 the point is encoded as an octet signifying the \s-1HYBRID\s0 form has been used \s-1AND\s0 which of the two possible solutions for y has been used, followed by the octets for x, followed by the octets for y. .PP The functions EC_GROUP_set_point_conversion_form and EC_GROUP_get_point_conversion_form set and get the point_conversion_form for the curve respectively. .PP \&\s-1ANSI\s0 X9.62 (\s-1ECDSA\s0 standard) defines a method of generating the curve parameter b from a random number. This provides advantages in that a parameter obtained in this way is highly unlikely to be susceptible to special purpose attacks, or have any trapdoors in it. If the seed is present for a curve then the b parameter was generated in a verifiable fashion using that seed. The OpenSSL \s-1EC\s0 library does not use this seed value but does enable you to inspect it using EC_GROUP_get0_seed. This returns a pointer to a memory block containing the seed that was used. The length of the memory block can be obtained using EC_GROUP_get_seed_len. A number of the builtin curves within the library provide seed values that can be obtained. It is also possible to set a custom seed using EC_GROUP_set_seed and passing a pointer to a memory block, along with the length of the seed. Again, the \s-1EC\s0 library will not use this seed value, although it will be preserved in any \s-1ASN1\s0 based communications. .PP EC_GROUP_get_degree gets the degree of the field. For Fp fields this will be the number of bits in p. For F2^m fields this will be the value m. .PP The function EC_GROUP_check_discriminant calculates the discriminant for the curve and verifies that it is valid. For a curve defined over Fp the discriminant is given by the formula 4*a^3 + 27*b^2 whilst for F2^m curves the discriminant is simply b. In either case for the curve to be valid the discriminant must be non zero. .PP The function EC_GROUP_check performs a number of checks on a curve to verify that it is valid. Checks performed include verifying that the discriminant is non zero; that a generator has been defined; that the generator is on the curve and has the correct order. .PP EC_GROUP_cmp compares \fBa\fR and \fBb\fR to determine whether they represent the same curve or not. .PP The functions EC_GROUP_get_basis_type, EC_GROUP_get_trinomial_basis and EC_GROUP_get_pentanomial_basis should only be called for curves defined over an F2^m field. Addition and multiplication operations within an F2^m field are performed using an irreducible polynomial function f(x). This function is either a trinomial of the form: .PP f(x) = x^m + x^k + 1 with m > k >= 1 .PP or a pentanomial of the form: .PP f(x) = x^m + x^k3 + x^k2 + x^k1 + 1 with m > k3 > k2 > k1 >= 1 .PP The function EC_GROUP_get_basis_type returns a \s-1NID\s0 identifying whether a trinomial or pentanomial is in use for the field. The function EC_GROUP_get_trinomial_basis must only be called where f(x) is of the trinomial form, and returns the value of \fBk\fR. Similary the function EC_GROUP_get_pentanomial_basis must only be called where f(x) is of the pentanomial form, and returns the values of \fBk1\fR, \&\fBk2\fR and \fBk3\fR respectively. .SH "RETURN VALUES" .IX Header "RETURN VALUES" The following functions return 1 on success or 0 on error: EC_GROUP_copy, EC_GROUP_set_generator, EC_GROUP_check, EC_GROUP_check_discriminant, EC_GROUP_get_trinomial_basis and EC_GROUP_get_pentanomial_basis. .PP EC_GROUP_dup returns a pointer to the duplicated curve, or \s-1NULL\s0 on error. .PP EC_GROUP_method_of returns the \s-1EC_METHOD\s0 implementation in use for the given curve or \s-1NULL\s0 on error. .PP EC_GROUP_get0_generator returns the generator for the given curve or \s-1NULL\s0 on error. .PP EC_GROUP_get_order, EC_GROUP_get_cofactor, EC_GROUP_get_curve_name, EC_GROUP_get_asn1_flag, EC_GROUP_get_point_conversion_form and EC_GROUP_get_degree return the order, cofactor, curve name (\s-1NID\s0), \s-1ASN1\s0 flag, point_conversion_form and degree for the specified curve respectively. If there is no curve name associated with a curve then EC_GROUP_get_curve_name will return 0. .PP EC_GROUP_get0_seed returns a pointer to the seed that was used to generate the parameter b, or \s-1NULL\s0 if the seed is not specified. EC_GROUP_get_seed_len returns the length of the seed or 0 if the seed is not specified. .PP EC_GROUP_set_seed returns the length of the seed that has been set. If the supplied seed is \s-1NULL\s0, or the supplied seed length is 0, the return value will be 1. On error 0 is returned. .PP EC_GROUP_cmp returns 0 if the curves are equal, 1 if they are not equal, or \-1 on error. .PP EC_GROUP_get_basis_type returns the values NID_X9_62_tpBasis or NID_X9_62_ppBasis (as defined in <openssl/obj_mac.h>) for a trinomial or pentanomial respectively. Alternatively in the event of an error a 0 is returned. .SH "SEE ALSO" .IX Header "SEE ALSO" \&\fIcrypto\fR\|(3), \fIec\fR\|(3), \fIEC_GROUP_new\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)