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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 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, less than
       RSA_size(rsa) - 41 for RSA_PKCS1_OAEP_PADDING and exactly RSA_size(rsa) for RSA_NO_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.



0.9.7l                                           2004-03-23                            RSA_public_encrypt(3)