name : RSA_PKCS1_OpenSSL.3 .\" Automatically generated by Pod::Man 4.11 (Pod::Simple 3.35) .\" .\" 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++. 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- .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" '' . ds C` . ds C' 'br\} .\" .\" Escape single quotes in literal strings from groff's Unicode transform. .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" .\" If the F register is >0, we'll generate index entries on stderr for .\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index .\" entries marked with X<> in POD. Of course, you'll have to process the .\" output yourself in some meaningful fashion. .\" .\" Avoid warning from groff about undefined register 'F'. .de IX .. .nr rF 0 .if \n(.g .if rF .nr rF 1 .if (\n(rF:(\n(.g==0)) \{\ . if \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{\ . nr % 0 . nr F 2 . \} . \} .\} .rr rF .\" .\" 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 "RSA_SET_METHOD 3" .TH RSA_SET_METHOD 3 "2023-09-11" "1.1.1w" "OpenSSL" .\" For nroff, turn off justification. Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH "NAME" RSA_set_default_method, RSA_get_default_method, RSA_set_method, RSA_get_method, RSA_PKCS1_OpenSSL, RSA_flags, RSA_new_method \- select RSA method .SH "SYNOPSIS" .IX Header "SYNOPSIS" .Vb 1 \& #include <openssl/rsa.h> \& \& void RSA_set_default_method(const RSA_METHOD *meth); \& \& RSA_METHOD *RSA_get_default_method(void); \& \& int RSA_set_method(RSA *rsa, const RSA_METHOD *meth); \& \& RSA_METHOD *RSA_get_method(const RSA *rsa); \& \& RSA_METHOD *RSA_PKCS1_OpenSSL(void); \& \& int RSA_flags(const RSA *rsa); \& \& RSA *RSA_new_method(ENGINE *engine); .Ve .SH "DESCRIPTION" .IX Header "DESCRIPTION" An \fB\s-1RSA_METHOD\s0\fR specifies the functions that OpenSSL uses for \s-1RSA\s0 operations. By modifying the method, alternative implementations such as hardware accelerators may be used. \s-1IMPORTANT:\s0 See the \s-1NOTES\s0 section for important information about how these \s-1RSA API\s0 functions are affected by the use of \fB\s-1ENGINE\s0\fR \s-1API\s0 calls. .PP Initially, the default \s-1RSA_METHOD\s0 is the OpenSSL internal implementation, as returned by \fBRSA_PKCS1_OpenSSL()\fR. .PP \&\fBRSA_set_default_method()\fR makes \fBmeth\fR the default method for all \s-1RSA\s0 structures created later. \&\fB\s-1NB\s0\fR: This is true only whilst no \s-1ENGINE\s0 has been set as a default for \s-1RSA,\s0 so this function is no longer recommended. This function is not thread-safe and should not be called at the same time as other OpenSSL functions. .PP \&\fBRSA_get_default_method()\fR returns a pointer to the current default \&\s-1RSA_METHOD.\s0 However, the meaningfulness of this result is dependent on whether the \s-1ENGINE API\s0 is being used, so this function is no longer recommended. .PP \&\fBRSA_set_method()\fR selects \fBmeth\fR to perform all operations using the key \&\fBrsa\fR. This will replace the \s-1RSA_METHOD\s0 used by the \s-1RSA\s0 key and if the previous method was supplied by an \s-1ENGINE,\s0 the handle to that \s-1ENGINE\s0 will be released during the change. It is possible to have \s-1RSA\s0 keys that only work with certain \s-1RSA_METHOD\s0 implementations (e.g. from an \s-1ENGINE\s0 module that supports embedded hardware-protected keys), and in such cases attempting to change the \s-1RSA_METHOD\s0 for the key can have unexpected results. .PP \&\fBRSA_get_method()\fR returns a pointer to the \s-1RSA_METHOD\s0 being used by \fBrsa\fR. This method may or may not be supplied by an \s-1ENGINE\s0 implementation, but if it is, the return value can only be guaranteed to be valid as long as the \&\s-1RSA\s0 key itself is valid and does not have its implementation changed by \&\fBRSA_set_method()\fR. .PP \&\fBRSA_flags()\fR returns the \fBflags\fR that are set for \fBrsa\fR's current \&\s-1RSA_METHOD.\s0 See the \s-1BUGS\s0 section. .PP \&\fBRSA_new_method()\fR allocates and initializes an \s-1RSA\s0 structure so that \&\fBengine\fR will be used for the \s-1RSA\s0 operations. If \fBengine\fR is \s-1NULL,\s0 the default \s-1ENGINE\s0 for \s-1RSA\s0 operations is used, and if no default \s-1ENGINE\s0 is set, the \s-1RSA_METHOD\s0 controlled by \fBRSA_set_default_method()\fR is used. .PP \&\fBRSA_flags()\fR returns the \fBflags\fR that are set for \fBrsa\fR's current method. .PP \&\fBRSA_new_method()\fR allocates and initializes an \fB\s-1RSA\s0\fR structure so that \&\fBmethod\fR will be used for the \s-1RSA\s0 operations. If \fBmethod\fR is \fB\s-1NULL\s0\fR, the default method is used. .SH "THE RSA_METHOD STRUCTURE" .IX Header "THE RSA_METHOD STRUCTURE" .Vb 4 \& typedef struct rsa_meth_st \& { \& /* name of the implementation */ \& const char *name; \& \& /* encrypt */ \& int (*rsa_pub_enc)(int flen, unsigned char *from, \& unsigned char *to, RSA *rsa, int padding); \& \& /* verify arbitrary data */ \& int (*rsa_pub_dec)(int flen, unsigned char *from, \& unsigned char *to, RSA *rsa, int padding); \& \& /* sign arbitrary data */ \& int (*rsa_priv_enc)(int flen, unsigned char *from, \& unsigned char *to, RSA *rsa, int padding); \& \& /* decrypt */ \& int (*rsa_priv_dec)(int flen, unsigned char *from, \& unsigned char *to, RSA *rsa, int padding); \& \& /* compute r0 = r0 ^ I mod rsa\->n (May be NULL for some implementations) */ \& int (*rsa_mod_exp)(BIGNUM *r0, BIGNUM *I, RSA *rsa); \& \& /* compute r = a ^ p mod m (May be NULL for some implementations) */ \& int (*bn_mod_exp)(BIGNUM *r, BIGNUM *a, const BIGNUM *p, \& const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx); \& \& /* called at RSA_new */ \& int (*init)(RSA *rsa); \& \& /* called at RSA_free */ \& int (*finish)(RSA *rsa); \& \& /* \& * RSA_FLAG_EXT_PKEY \- rsa_mod_exp is called for private key \& * operations, even if p,q,dmp1,dmq1,iqmp \& * are NULL \& * RSA_METHOD_FLAG_NO_CHECK \- don\*(Aqt check pub/private match \& */ \& int flags; \& \& char *app_data; /* ?? */ \& \& int (*rsa_sign)(int type, \& const unsigned char *m, unsigned int m_length, \& unsigned char *sigret, unsigned int *siglen, const RSA *rsa); \& int (*rsa_verify)(int dtype, \& const unsigned char *m, unsigned int m_length, \& const unsigned char *sigbuf, unsigned int siglen, \& const RSA *rsa); \& /* keygen. If NULL builtin RSA key generation will be used */ \& int (*rsa_keygen)(RSA *rsa, int bits, BIGNUM *e, BN_GENCB *cb); \& \& } RSA_METHOD; .Ve .SH "RETURN VALUES" .IX Header "RETURN VALUES" \&\fBRSA_PKCS1_OpenSSL()\fR, \fBRSA_PKCS1_null_method()\fR, \fBRSA_get_default_method()\fR and \fBRSA_get_method()\fR return pointers to the respective RSA_METHODs. .PP \&\fBRSA_set_default_method()\fR returns no value. .PP \&\fBRSA_set_method()\fR returns a pointer to the old \s-1RSA_METHOD\s0 implementation that was replaced. However, this return value should probably be ignored because if it was supplied by an \s-1ENGINE,\s0 the pointer could be invalidated at any time if the \s-1ENGINE\s0 is unloaded (in fact it could be unloaded as a result of the \fBRSA_set_method()\fR function releasing its handle to the \&\s-1ENGINE\s0). For this reason, the return type may be replaced with a \fBvoid\fR declaration in a future release. .PP \&\fBRSA_new_method()\fR returns \s-1NULL\s0 and sets an error code that can be obtained by \fBERR_get_error\fR\|(3) if the allocation fails. Otherwise it returns a pointer to the newly allocated structure. .SH "BUGS" .IX Header "BUGS" The behaviour of \fBRSA_flags()\fR is a mis-feature that is left as-is for now to avoid creating compatibility problems. \s-1RSA\s0 functionality, such as the encryption functions, are controlled by the \fBflags\fR value in the \s-1RSA\s0 key itself, not by the \fBflags\fR value in the \s-1RSA_METHOD\s0 attached to the \s-1RSA\s0 key (which is what this function returns). If the flags element of an \s-1RSA\s0 key is changed, the changes will be honoured by \s-1RSA\s0 functionality but will not be reflected in the return value of the \fBRSA_flags()\fR function \- in effect \&\fBRSA_flags()\fR behaves more like an \fBRSA_default_flags()\fR function (which does not currently exist). .SH "SEE ALSO" .IX Header "SEE ALSO" \&\fBRSA_new\fR\|(3) .SH "HISTORY" .IX Header "HISTORY" The \fBRSA_null_method()\fR, which was a partial attempt to avoid patent issues, was replaced to always return \s-1NULL\s0 in OpenSSL 1.1.1. .SH "COPYRIGHT" .IX Header "COPYRIGHT" Copyright 2000\-2020 The OpenSSL Project Authors. All Rights Reserved. .PP Licensed under the OpenSSL license (the \*(L"License\*(R"). You may not use this file except in compliance with the License. You can obtain a copy in the file \s-1LICENSE\s0 in the source distribution or at <https://www.openssl.org/source/license.html>.