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).
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.