RSA_public_encrypt(3)						      OpenSSL						     RSA_public_encrypt(3)

NAME

       RSA_public_encrypt, RSA_private_decrypt - RSA public key cryptography

SYNOPSIS

	#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

       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 applica-
	   tions.

       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.  Encrypt-
	   ing 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

       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

       SSL, PKCS #1 v2.0

SEE ALSO

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

HISTORY

       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.

0.9.7a								    2002-09-25						     RSA_public_encrypt(3)