RSA_public_encrypt - RSA public key cryptography
#include <openssl/rsa.h> int RSA_public_encrypt(int flen, const unsigned char *from, unsigned char *to, RSA *rsa, int padding); int RSA_private_decrypt(int flen, const unsigned char *from, unsigned char *to, RSA *rsa, int padding);
OpenSSL RSA_public_encrypt(3openssl)
NAME
RSA_public_encrypt, RSA_private_decrypt - RSA public key cryptography
SYNOPSIS
#include <openssl/rsa.h>
int RSA_public_encrypt(int flen, const unsigned char *from,
unsigned char *to, RSA *rsa, int padding);
int RSA_private_decrypt(int flen, const 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).
WARNING
Decryption failures in the RSA_PKCS1_PADDING mode leak information
which can potentially be used to mount a Bleichenbacher padding oracle
attack. This is an inherent weakness in the PKCS #1 v1.5 padding
design. Prefer RSA_PKCS1_OAEP_PADDING.
CONFORMING TO
SSL, PKCS #1 v2.0
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
+---------------+--------------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+--------------------------+
|Availability | library/security/openssl |
+---------------+--------------------------+
|Stability | Pass-through uncommitted |
+---------------+--------------------------+
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.
NOTES
Source code for open source software components in Oracle Solaris can
be found at https://www.oracle.com/downloads/opensource/solaris-source-
code-downloads.html.
This software was built from source available at
https://github.com/oracle/solaris-userland. The original community
source was downloaded from
https://www.openssl.org/source/openssl-1.0.2ze.tar.gz.
Further information about this software can be found on the open source
community website at https://www.openssl.org/.
1.0.2ze 2022-05-03
RSA_public_encrypt(3openssl)