RSA_public_encrypt(3)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
The RSA_public_encrypt() function encrypts the flen bytes at from (usu‐
ally a session key) using the public key rsa and stores the ciphertext
in to. The to must point to RSA_size(rsa) bytes of memory.
The padding denotes one of the following modes: PKCS #1 v1.5 padding.
This currently is the most widely used mode. 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. PKCS #1 v1.5 padding
with an SSL-specific modification that denotes that the server is SSL3
capable. Raw RSA encryption. This mode should only be used to imple‐
ment cryptographically sound padding modes in the application code.
Encrypting user data directly with RSA is insecure.
The 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 the RSA_public_encrypt() function.
The RSA_private_decrypt() function decrypts the flen bytes at from
using the private key rsa and stores the plaintext in to. The to must
point to a memory section large enough to hold the decrypted data ,
which is smaller than RSA_size(rsa). The padding is the padding mode
that was used to encrypt the data.
These functions conform to SSL, PKCS #1 v2.0.
NOTES
The RSA_PKCS1_RSAref(3) method supports only the RSA_PKCS1_PADDING
mode.
RETURN VALUES
The RSA_public_encrypt() function returns the size of the encrypted
data, RSA_size(rsa). The RSA_private_decrypt() function returns the
size of the recovered plaintext.
On error, -1 is returned; the error codes can be obtained by using the
ERR_get_error() function.
HISTORY
The padding argument was added in SSLeay 0.8. RSA_NO_PADDING is avail‐
able since SSLeay 0.9.0, OAEP was added in OpenSSL 0.9.2b.
SEE ALSO
Functions: err(3), rand_ssl(3), rsa(3), RSA_size(3)RSA_public_encrypt(3)