# rsa_public_encrypt(3) [redhat man page]

RSA_public_encrypt(3) OpenSSL RSA_public_encrypt(3)NAME

RSA_public_encrypt, RSA_private_decrypt - RSA public key cryptographySYNOPSIS

#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 applica- tions. 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. Encrypt- ing 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

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,is returned; the error codes can be obtained by ERR_get_error(3).-1CONFORMING TO

SSL, PKCS #1 v2.0SEE 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.0.9.7a2002-09-25 RSA_public_encrypt(3)

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RSA_public_encrypt(3) OpenSSL RSA_public_encrypt(3)NAME

RSA_public_encrypt, RSA_private_decrypt - RSA public key cryptographySYNOPSIS

#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 applica- tions. 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. Encrypt- ing 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

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,is returned; the error codes can be obtained by ERR_get_error(3).-1CONFORMING TO

SSL, PKCS #1 v2.0SEE 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.0.9.7d2003-11-20 RSA_public_encrypt(3)