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.\" ========================================================================
.\"
.IX Title "RSA_METH_NEW 3"
.TH RSA_METH_NEW 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_meth_get0_app_data, RSA_meth_set0_app_data, RSA_meth_new, RSA_meth_free, RSA_meth_dup, RSA_meth_get0_name, RSA_meth_set1_name, RSA_meth_get_flags, RSA_meth_set_flags, RSA_meth_get_pub_enc, RSA_meth_set_pub_enc, RSA_meth_get_pub_dec, RSA_meth_set_pub_dec, RSA_meth_get_priv_enc, RSA_meth_set_priv_enc, RSA_meth_get_priv_dec, RSA_meth_set_priv_dec, RSA_meth_get_mod_exp, RSA_meth_set_mod_exp, RSA_meth_get_bn_mod_exp, RSA_meth_set_bn_mod_exp, RSA_meth_get_init, RSA_meth_set_init, RSA_meth_get_finish, RSA_meth_set_finish, RSA_meth_get_sign, RSA_meth_set_sign, RSA_meth_get_verify, RSA_meth_set_verify, RSA_meth_get_keygen, RSA_meth_set_keygen, RSA_meth_get_multi_prime_keygen, RSA_meth_set_multi_prime_keygen \&\- Routines to build up RSA methods
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& #include <openssl/rsa.h>
\&
\& RSA_METHOD *RSA_meth_new(const char *name, int flags);
\& void RSA_meth_free(RSA_METHOD *meth);
\&
\& RSA_METHOD *RSA_meth_dup(const RSA_METHOD *meth);
\&
\& const char *RSA_meth_get0_name(const RSA_METHOD *meth);
\& int RSA_meth_set1_name(RSA_METHOD *meth, const char *name);
\&
\& int RSA_meth_get_flags(const RSA_METHOD *meth);
\& int RSA_meth_set_flags(RSA_METHOD *meth, int flags);
\&
\& void *RSA_meth_get0_app_data(const RSA_METHOD *meth);
\& int RSA_meth_set0_app_data(RSA_METHOD *meth, void *app_data);
\&
\& int (*RSA_meth_get_pub_enc(const RSA_METHOD *meth))(int flen, const unsigned char *from,
\&                                                     unsigned char *to, RSA *rsa, int padding);
\& int RSA_meth_set_pub_enc(RSA_METHOD *rsa,
\&                          int (*pub_enc)(int flen, const unsigned char *from,
\&                                         unsigned char *to, RSA *rsa,
\&                                         int padding));
\&
\& int (*RSA_meth_get_pub_dec(const RSA_METHOD *meth))
\&     (int flen, const unsigned char *from,
\&      unsigned char *to, RSA *rsa, int padding);
\& int RSA_meth_set_pub_dec(RSA_METHOD *rsa,
\&                          int (*pub_dec)(int flen, const unsigned char *from,
\&                                         unsigned char *to, RSA *rsa,
\&                                         int padding));
\&
\& int (*RSA_meth_get_priv_enc(const RSA_METHOD *meth))(int flen, const unsigned char *from,
\&                                                      unsigned char *to, RSA *rsa,
\&                                                      int padding);
\& int RSA_meth_set_priv_enc(RSA_METHOD *rsa,
\&                           int (*priv_enc)(int flen, const unsigned char *from,
\&                                           unsigned char *to, RSA *rsa, int padding));
\&
\& int (*RSA_meth_get_priv_dec(const RSA_METHOD *meth))(int flen, const unsigned char *from,
\&                                                      unsigned char *to, RSA *rsa,
\&                                                      int padding);
\& int RSA_meth_set_priv_dec(RSA_METHOD *rsa,
\&                           int (*priv_dec)(int flen, const unsigned char *from,
\&                                           unsigned char *to, RSA *rsa, int padding));
\&
\& /* Can be null */
\& int (*RSA_meth_get_mod_exp(const RSA_METHOD *meth))(BIGNUM *r0, const BIGNUM *i,
\&                                                     RSA *rsa, BN_CTX *ctx);
\& int RSA_meth_set_mod_exp(RSA_METHOD *rsa,
\&                          int (*mod_exp)(BIGNUM *r0, const BIGNUM *i, RSA *rsa,
\&                                         BN_CTX *ctx));
\&
\& /* Can be null */
\& int (*RSA_meth_get_bn_mod_exp(const RSA_METHOD *meth))(BIGNUM *r, const BIGNUM *a,
\&                                                        const BIGNUM *p, const BIGNUM *m,
\&                                                        BN_CTX *ctx, BN_MONT_CTX *m_ctx);
\& int RSA_meth_set_bn_mod_exp(RSA_METHOD *rsa,
\&                             int (*bn_mod_exp)(BIGNUM *r, const BIGNUM *a,
\&                                               const BIGNUM *p, const BIGNUM *m,
\&                                               BN_CTX *ctx, BN_MONT_CTX *m_ctx));
\&
\& /* called at new */
\& int (*RSA_meth_get_init(const RSA_METHOD *meth) (RSA *rsa);
\& int RSA_meth_set_init(RSA_METHOD *rsa, int (*init (RSA *rsa));
\&
\& /* called at free */
\& int (*RSA_meth_get_finish(const RSA_METHOD *meth))(RSA *rsa);
\& int RSA_meth_set_finish(RSA_METHOD *rsa, int (*finish)(RSA *rsa));
\&
\& int (*RSA_meth_get_sign(const RSA_METHOD *meth))(int type, const unsigned char *m,
\&                                                  unsigned int m_length,
\&                                                  unsigned char *sigret,
\&                                                  unsigned int *siglen, const RSA *rsa);
\& int RSA_meth_set_sign(RSA_METHOD *rsa,
\&                       int (*sign)(int type, const unsigned char *m,
\&                                   unsigned int m_length, unsigned char *sigret,
\&                                   unsigned int *siglen, const RSA *rsa));
\&
\& int (*RSA_meth_get_verify(const RSA_METHOD *meth))(int dtype, const unsigned char *m,
\&                                                    unsigned int m_length,
\&                                                    const unsigned char *sigbuf,
\&                                                    unsigned int siglen, const RSA *rsa);
\& int RSA_meth_set_verify(RSA_METHOD *rsa,
\&                         int (*verify)(int dtype, const unsigned char *m,
\&                                       unsigned int m_length,
\&                                       const unsigned char *sigbuf,
\&                                       unsigned int siglen, const RSA *rsa));
\&
\& int (*RSA_meth_get_keygen(const RSA_METHOD *meth))(RSA *rsa, int bits, BIGNUM *e,
\&                                                    BN_GENCB *cb);
\& int RSA_meth_set_keygen(RSA_METHOD *rsa,
\&                         int (*keygen)(RSA *rsa, int bits, BIGNUM *e,
\&                                       BN_GENCB *cb));
\&
\& int (*RSA_meth_get_multi_prime_keygen(const RSA_METHOD *meth))(RSA *rsa, int bits,
\&                                                                int primes, BIGNUM *e,
\&                                                                BN_GENCB *cb);
\&
\& int RSA_meth_set_multi_prime_keygen(RSA_METHOD *meth,
\&                                     int (*keygen) (RSA *rsa, int bits,
\&                                                    int primes, BIGNUM *e,
\&                                                    BN_GENCB *cb));
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
The \fB\s-1RSA_METHOD\s0\fR type is a structure used for the provision of custom
\&\s-1RSA\s0 implementations. It provides a set of functions used by OpenSSL
for the implementation of the various \s-1RSA\s0 capabilities. See the rsa
page for more information.
.PP
\&\fBRSA_meth_new()\fR creates a new \fB\s-1RSA_METHOD\s0\fR structure. It should be
given a unique \fBname\fR and a set of \fBflags\fR. The \fBname\fR should be a
\&\s-1NULL\s0 terminated string, which will be duplicated and stored in the
\&\fB\s-1RSA_METHOD\s0\fR object. It is the callers responsibility to free the
original string. The flags will be used during the construction of a
new \fB\s-1RSA\s0\fR object based on this \fB\s-1RSA_METHOD\s0\fR. Any new \fB\s-1RSA\s0\fR object
will have those flags set by default.
.PP
\&\fBRSA_meth_dup()\fR creates a duplicate copy of the \fB\s-1RSA_METHOD\s0\fR object
passed as a parameter. This might be useful for creating a new
\&\fB\s-1RSA_METHOD\s0\fR based on an existing one, but with some differences.
.PP
\&\fBRSA_meth_free()\fR destroys an \fB\s-1RSA_METHOD\s0\fR structure and frees up any
memory associated with it.
.PP
\&\fBRSA_meth_get0_name()\fR will return a pointer to the name of this
\&\s-1RSA_METHOD.\s0 This is a pointer to the internal name string and so
should not be freed by the caller. \fBRSA_meth_set1_name()\fR sets the name
of the \s-1RSA_METHOD\s0 to \fBname\fR. The string is duplicated and the copy is
stored in the \s-1RSA_METHOD\s0 structure, so the caller remains responsible
for freeing the memory associated with the name.
.PP
\&\fBRSA_meth_get_flags()\fR returns the current value of the flags associated
with this \s-1RSA_METHOD.\s0 \fBRSA_meth_set_flags()\fR provides the ability to set
these flags.
.PP
The functions \fBRSA_meth_get0_app_data()\fR and \fBRSA_meth_set0_app_data()\fR
provide the ability to associate implementation specific data with the
\&\s-1RSA_METHOD.\s0 It is the application's responsibility to free this data
before the \s-1RSA_METHOD\s0 is freed via a call to \fBRSA_meth_free()\fR.
.PP
\&\fBRSA_meth_get_sign()\fR and \fBRSA_meth_set_sign()\fR get and set the function
used for creating an \s-1RSA\s0 signature respectively. This function will be
called in response to the application calling \fBRSA_sign()\fR. The
parameters for the function have the same meaning as for \fBRSA_sign()\fR.
.PP
\&\fBRSA_meth_get_verify()\fR and \fBRSA_meth_set_verify()\fR get and set the
function used for verifying an \s-1RSA\s0 signature respectively. This
function will be called in response to the application calling
\&\fBRSA_verify()\fR. The parameters for the function have the same meaning as
for \fBRSA_verify()\fR.
.PP
\&\fBRSA_meth_get_mod_exp()\fR and \fBRSA_meth_set_mod_exp()\fR get and set the
function used for \s-1CRT\s0 computations.
.PP
\&\fBRSA_meth_get_bn_mod_exp()\fR and \fBRSA_meth_set_bn_mod_exp()\fR get and set
the function used for \s-1CRT\s0 computations, specifically the following
value:
.PP
.Vb 1
\& r = a ^ p mod m
.Ve
.PP
Both the \fBmod_exp()\fR and \fBbn_mod_exp()\fR functions are called by the
default OpenSSL method during encryption, decryption, signing and
verification.
.PP
\&\fBRSA_meth_get_init()\fR and \fBRSA_meth_set_init()\fR get and set the function
used for creating a new \s-1RSA\s0 instance respectively. This function will
be called in response to the application calling \fBRSA_new()\fR (if the
current default \s-1RSA_METHOD\s0 is this one) or \fBRSA_new_method()\fR. The
\&\fBRSA_new()\fR and \fBRSA_new_method()\fR functions will allocate the memory for
the new \s-1RSA\s0 object, and a pointer to this newly allocated structure
will be passed as a parameter to the function. This function may be
\&\s-1NULL.\s0
.PP
\&\fBRSA_meth_get_finish()\fR and \fBRSA_meth_set_finish()\fR get and set the
function used for destroying an instance of an \s-1RSA\s0 object respectively.
This function will be called in response to the application calling
\&\fBRSA_free()\fR. A pointer to the \s-1RSA\s0 to be destroyed is passed as a
parameter. The destroy function should be used for \s-1RSA\s0 implementation
specific clean up. The memory for the \s-1RSA\s0 itself should not be freed
by this function. This function may be \s-1NULL.\s0
.PP
\&\fBRSA_meth_get_keygen()\fR and \fBRSA_meth_set_keygen()\fR get and set the
function used for generating a new \s-1RSA\s0 key pair respectively. This
function will be called in response to the application calling
\&\fBRSA_generate_key_ex()\fR. The parameter for the function has the same
meaning as for \fBRSA_generate_key_ex()\fR.
.PP
\&\fBRSA_meth_get_multi_prime_keygen()\fR and \fBRSA_meth_set_multi_prime_keygen()\fR get
and set the function used for generating a new multi-prime \s-1RSA\s0 key pair
respectively. This function will be called in response to the application calling
\&\fBRSA_generate_multi_prime_key()\fR. The parameter for the function has the same
meaning as for \fBRSA_generate_multi_prime_key()\fR.
.PP
\&\fBRSA_meth_get_pub_enc()\fR, \fBRSA_meth_set_pub_enc()\fR,
\&\fBRSA_meth_get_pub_dec()\fR, \fBRSA_meth_set_pub_dec()\fR,
\&\fBRSA_meth_get_priv_enc()\fR, \fBRSA_meth_set_priv_enc()\fR,
\&\fBRSA_meth_get_priv_dec()\fR, \fBRSA_meth_set_priv_dec()\fR get and set the
functions used for public and private key encryption and decryption.
These functions will be called in response to the application calling
\&\fBRSA_public_encrypt()\fR, \fBRSA_private_decrypt()\fR, \fBRSA_private_encrypt()\fR and
\&\fBRSA_public_decrypt()\fR and take the same parameters as those.
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
\&\fBRSA_meth_new()\fR and \fBRSA_meth_dup()\fR return the newly allocated
\&\s-1RSA_METHOD\s0 object or \s-1NULL\s0 on failure.
.PP
\&\fBRSA_meth_get0_name()\fR and \fBRSA_meth_get_flags()\fR return the name and
flags associated with the \s-1RSA_METHOD\s0 respectively.
.PP
All other RSA_meth_get_*() functions return the appropriate function
pointer that has been set in the \s-1RSA_METHOD,\s0 or \s-1NULL\s0 if no such
pointer has yet been set.
.PP
RSA_meth_set1_name and all RSA_meth_set_*() functions return 1 on
success or 0 on failure.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fBRSA_new\fR\|(3), \fBRSA_generate_key_ex\fR\|(3), \fBRSA_sign\fR\|(3),
\&\fBRSA_set_method\fR\|(3), \fBRSA_size\fR\|(3), \fBRSA_get0_key\fR\|(3),
\&\fBRSA_generate_multi_prime_key\fR\|(3)
.SH "HISTORY"
.IX Header "HISTORY"
\&\fBRSA_meth_get_multi_prime_keygen()\fR and \fBRSA_meth_set_multi_prime_keygen()\fR were
added in OpenSSL 1.1.1.
.PP
Other functions described here were added in OpenSSL 1.1.0.
.SH "COPYRIGHT"
.IX Header "COPYRIGHT"
Copyright 2016\-2018 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>.