RSA_public_encrypt(3)

     RSA_public_encrypt(3)  0.9.6h (2002-09-25)  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, 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

     Page 1                                         (printed 1/19/103)

     RSA_public_encrypt(3)  0.9.6h (2002-09-25)  RSA_public_encrypt(3)

          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)

     NOTES
          The RSA_PKCS1_RSAref(3) method supports only the
          RSA_PKCS1_PADDING mode.

     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.

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