path: root/secure/lib/libcrypto/man/RSA_set_method.3

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.\"
.IX Title "RSA_SET_METHOD 1"
.TH RSA_SET_METHOD 1 "perl v5.6.1" "2000-11-13" "User Contributed Perl Documentation"
.UC
.SH "NAME"
RSA_set_default_method, RSA_get_default_method, RSA_set_method,
RSA_get_method, RSA_PKCS1_SSLeay, RSA_PKCS1_RSAref,
RSA_null_method, RSA_flags, RSA_new_method \- select \s-1RSA\s0 method
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& #include <openssl/rsa.h>
.Ve
.Vb 1
\& void RSA_set_default_method(RSA_METHOD *meth);
.Ve
.Vb 1
\& RSA_METHOD *RSA_get_default_method(void);
.Ve
.Vb 1
\& RSA_METHOD *RSA_set_method(RSA *rsa, RSA_METHOD *meth);
.Ve
.Vb 1
\& RSA_METHOD *RSA_get_method(RSA *rsa);
.Ve
.Vb 1
\& RSA_METHOD *RSA_PKCS1_SSLeay(void);
.Ve
.Vb 1
\& RSA_METHOD *RSA_PKCS1_RSAref(void);
.Ve
.Vb 1
\& RSA_METHOD *RSA_null_method(void);
.Ve
.Vb 1
\& int RSA_flags(RSA *rsa);
.Ve
.Vb 1
\& RSA *RSA_new_method(RSA_METHOD *method);
.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.
.PP
Initially, the default is to use the OpenSSL internal implementation,
unless OpenSSL was configured with the \f(CW\*(C`rsaref\*(C'\fR or \f(CW\*(C`\-DRSA_NULL\*(C'\fR
options. \fIRSA_PKCS1_SSLeay()\fR returns a pointer to that method.
.PP
\&\fIRSA_PKCS1_RSAref()\fR returns a pointer to a method that uses the RSAref
library. This is the default method in the \f(CW\*(C`rsaref\*(C'\fR configuration;
the function is not available in other configurations.
\&\fIRSA_null_method()\fR returns a pointer to a method that does not support
the \s-1RSA\s0 transformation. It is the default if OpenSSL is compiled with
\&\f(CW\*(C`\-DRSA_NULL\*(C'\fR. These methods may be useful in the \s-1USA\s0 because of a
patent on the \s-1RSA\s0 cryptosystem.
.PP
\&\fIRSA_set_default_method()\fR makes \fBmeth\fR the default method for all \fB\s-1RSA\s0\fR
structures created later.
.PP
\&\fIRSA_get_default_method()\fR returns a pointer to the current default
method.
.PP
\&\fIRSA_set_method()\fR selects \fBmeth\fR for all operations using the key
\&\fBrsa\fR.
.PP
\&\fIRSA_get_method()\fR returns a pointer to the method currently selected
for \fBrsa\fR.
.PP
\&\fIRSA_flags()\fR returns the \fBflags\fR that are set for \fBrsa\fR's current method.
.PP
\&\fIRSA_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;
.Ve
.Vb 3
\&     /* encrypt */
\&        int (*rsa_pub_enc)(int flen, unsigned char *from,
\&          unsigned char *to, RSA *rsa, int padding);
.Ve
.Vb 3
\&     /* verify arbitrary data */
\&        int (*rsa_pub_dec)(int flen, unsigned char *from,
\&          unsigned char *to, RSA *rsa, int padding);
.Ve
.Vb 3
\&     /* sign arbitrary data */
\&        int (*rsa_priv_enc)(int flen, unsigned char *from,
\&          unsigned char *to, RSA *rsa, int padding);
.Ve
.Vb 3
\&     /* decrypt */
\&        int (*rsa_priv_dec)(int flen, unsigned char *from,
\&          unsigned char *to, RSA *rsa, int padding);
.Ve
.Vb 3
\&     /* compute r0 = r0 ^ I mod rsa->n (May be NULL for some
\&                                        implementations) */
\&        int (*rsa_mod_exp)(BIGNUM *r0, BIGNUM *I, RSA *rsa);
.Ve
.Vb 3
\&     /* 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);
.Ve
.Vb 2
\&     /* called at RSA_new */
\&        int (*init)(RSA *rsa);
.Ve
.Vb 2
\&     /* called at RSA_free */
\&        int (*finish)(RSA *rsa);
.Ve
.Vb 7
\&     /* RSA_FLAG_EXT_PKEY        - rsa_mod_exp is called for private key
\&      *                            operations, even if p,q,dmp1,dmq1,iqmp
\&      *                            are NULL
\&      * RSA_FLAG_SIGN_VER        - enable rsa_sign and rsa_verify
\&      * RSA_METHOD_FLAG_NO_CHECK - don't check pub/private match
\&      */
\&        int flags;
.Ve
.Vb 1
\&        char *app_data; /* ?? */
.Ve
.Vb 5
\&     /* sign. For backward compatibility, this is used only
\&      * if (flags & RSA_FLAG_SIGN_VER)
\&      */
\&        int (*rsa_sign)(int type, unsigned char *m, unsigned int m_len,
\&           unsigned char *sigret, unsigned int *siglen, RSA *rsa);
.Ve
.Vb 5
\&     /* verify. For backward compatibility, this is used only
\&      * if (flags & RSA_FLAG_SIGN_VER)
\&      */
\&        int (*rsa_verify)(int type, unsigned char *m, unsigned int m_len,
\&           unsigned char *sigbuf, unsigned int siglen, RSA *rsa);
.Ve
.Vb 1
\& } RSA_METHOD;
.Ve
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
\&\fIRSA_PKCS1_SSLeay()\fR, \fIRSA_PKCS1_RSAref()\fR, \fIRSA_PKCS1_null_method()\fR,
\&\fIRSA_get_default_method()\fR and \fIRSA_get_method()\fR return pointers to the
respective \fB\s-1RSA_METHOD\s0\fRs.
.PP
\&\fIRSA_set_default_method()\fR returns no value.
.PP
\&\fIRSA_set_method()\fR returns a pointer to the \fB\s-1RSA_METHOD\s0\fR previously
associated with \fBrsa\fR.
.PP
\&\fIRSA_new_method()\fR returns \fB\s-1NULL\s0\fR and sets an error code that can be
obtained by ERR_get_error(3) if the allocation fails. Otherwise it
returns a pointer to the newly allocated structure.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
rsa(3), RSA_new(3)
.SH "HISTORY"
.IX Header "HISTORY"
\&\fIRSA_new_method()\fR and \fIRSA_set_default_method()\fR appeared in SSLeay 0.8.
\&\fIRSA_get_default_method()\fR, \fIRSA_set_method()\fR and \fIRSA_get_method()\fR as
well as the rsa_sign and rsa_verify components of \s-1RSA_METHOD\s0 were
added in OpenSSL 0.9.4.