rsa(3)

NAME
rsa - RSA public key cryptosystem

SYNOPSIS
 #include <openssl/rsa.h>
 RSA * RSA_new(void);
 void RSA_free(RSA *rsa);
 int RSA_public_encrypt(int flen, unsigned char *from,
    unsigned char *to, RSA *rsa, int padding);
 int RSA_private_decrypt(int flen, unsigned char *from,
    unsigned char *to, RSA *rsa, int padding);
 int RSA_sign(int type, unsigned char *m, unsigned int m_len,
    unsigned char *sigret, unsigned int *siglen, RSA *rsa);
 int RSA_verify(int type, unsigned char *m, unsigned int m_len,
    unsigned char *sigbuf, unsigned int siglen, RSA *rsa);
 int RSA_size(RSA *rsa);
 RSA *RSA_generate_key(int num, unsigned long e,
    void (*callback)(int,int,void *), void *cb_arg);
 int RSA_check_key(RSA *rsa);
 int RSA_blinding_on(RSA *rsa, BN_CTX *ctx);
 void RSA_blinding_off(RSA *rsa);
 void RSA_set_default_method(RSA_METHOD *meth);
 RSA_METHOD *RSA_get_default_method(void);
 RSA_METHOD *RSA_set_method(RSA *rsa, RSA_METHOD *meth);
 RSA_METHOD *RSA_get_method(RSA *rsa);
 RSA_METHOD *RSA_PKCS1_SSLeay(void);
 RSA_METHOD *RSA_PKCS1_RSAref(void);
 RSA_METHOD *RSA_null_method(void);
 int RSA_flags(RSA *rsa);
 RSA *RSA_new_method(RSA_METHOD *method);
 int RSA_print(BIO *bp, RSA *x, int offset);
 int RSA_print_fp(FILE *fp, RSA *x, int offset);
 int RSA_get_ex_new_index(long argl, char *argp, int (*new_func)(),
    int (*dup_func)(), void (*free_func)());
 int RSA_set_ex_data(RSA *r,int idx,char *arg);
 char *RSA_get_ex_data(RSA *r, int idx);
 int RSA_private_encrypt(int flen, unsigned char *from,
    unsigned char *to, RSA *rsa,int padding);
 int RSA_public_decrypt(int flen, unsigned char *from,
    unsigned char *to, RSA *rsa,int padding);
 int RSA_sign_ASN1_OCTET_STRING(int dummy, unsigned char *m,
    unsigned int m_len, unsigned char *sigret, unsigned int *siglen,
    RSA *rsa);
 int RSA_verify_ASN1_OCTET_STRING(int dummy, unsigned char *m,
    unsigned int m_len, unsigned char *sigbuf, unsigned int siglen,
    RSA *rsa);

DESCRIPTION
These functions implement RSA public key encryption and signatures as defined in PKCS #1 v2.0 [RFC 2437].

The RSA structure consists of several BIGNUM components. It can contain public as well as private RSA keys:

 struct
        {
        BIGNUM *n;              // public modulus
        BIGNUM *e;              // public exponent
        BIGNUM *d;              // private exponent
        BIGNUM *p;              // secret prime factor
        BIGNUM *q;              // secret prime factor
        BIGNUM *dmp1;           // d mod (p-1)
        BIGNUM *dmq1;           // d mod (q-1)
        BIGNUM *iqmp;           // q^-1 mod p
        // ...
        };
 RSA
In public keys, the private exponent and the related secret values are NULL.

p, q, dmp1, dmq1 and iqmp may be NULL in private keys, but the RSA operations are much faster when these values are available.

CONFORMING TO
SSL, PKCS #1 v2.0

PATENTS
RSA was covered by a US patent which expired in September 2000.

SEE ALSO
rsa(1), bn(3), dsa(3), dh(3), rand(3), RSA_new(3), RSA_public_encrypt(3), RSA_sign(3), RSA_size(3), RSA_generate_key(3), RSA_check_key(3), RSA_blinding_on(3), RSA_set_method(3), RSA_print(3), RSA_get_ex_new_index(3), RSA_private_encrypt(3), RSA_sign_ASN1_OCTET_STRING(3), RSA_padding_add_PKCS1_type_1(3)