NAME    [Toc]    [Back]

       RSA_public_encrypt, RSA_private_decrypt - RSA public key
       cryptography

SYNOPSIS    [Toc]    [Back]

        #include <openssl/rsa.h>

        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);

DESCRIPTION    [Toc]    [Back]

       RSA_public_encrypt() encrypts the flen bytes at from (usually
 a session key) using the public key rsa and stores
       the ciphertext in to. to must point to RSA_size(rsa) bytes
       of memory.

       padding denotes one of the following modes:

       RSA_PKCS1_PADDING
           PKCS #1 v1.5 padding. This currently is the most
           widely used mode.

       RSA_PKCS1_OAEP_PADDING
           EME-OAEP as defined in PKCS #1 v2.0 with SHA-1, MGF1
           and an empty encoding parameter. This mode is recommended
 for all new applications.

       RSA_SSLV23_PADDING
           PKCS #1 v1.5 padding with an SSL-specific modification
           that denotes that the server is SSL3 capable.

       RSA_NO_PADDING
           Raw RSA encryption. This mode should only be used to
           implement cryptographically sound padding modes in the
           application code.  Encrypting user data directly with
           RSA is insecure.

       flen must be less than RSA_size(rsa) - 11 for the PKCS #1
       v1.5 based padding modes, and less than RSA_size(rsa) - 41
       for RSA_PKCS1_OAEP_PADDING. The random number generator
       must be seeded prior to calling RSA_public_encrypt().

       RSA_private_decrypt() decrypts the flen bytes at from
       using  the private key rsa and stores the plaintext in to.
       to must point to a memory section large enough to hold the
       decrypted data (which is smaller than RSA_size(rsa)).
       padding is the padding mode that was used to encrypt the
       data.

RETURN VALUES    [Toc]    [Back]

       RSA_public_encrypt() returns the size of the encrypted
       data (i.e., RSA_size(rsa)). RSA_private_decrypt() returns
       the size of the recovered plaintext.

       On error, -1 is returned; the error codes can be obtained
       by ERR_get_error(3).

CONFORMING TO    [Toc]    [Back]

       SSL, PKCS #1 v2.0

SEE ALSO    [Toc]    [Back]

       ERR_get_error(3), rand(3), rsa(3), RSA_size(3)

HISTORY    [Toc]    [Back]

       The padding argument was added in SSLeay 0.8.
       RSA_NO_PADDING is available since SSLeay 0.9.0, OAEP was
       added in OpenSSL 0.9.2b.


OpenBSD 3.6                 2003-05-11                          2