RSA_blinding_on 3 2000-07-16 0.9.9-dev OpenSSL

### NAME

RSA_blinding_on, RSA_blinding_off - protect the RSA operation from timing attacks

### LIBRARY

libcrypto, -lcrypto

### SYNOPSIS

     #include

     int RSA_blinding_on(RSA *rsa, BN_CTX *ctx);

     void RSA_blinding_off(RSA *rsa);

### DESCRIPTION

RSA is vulnerable to timing attacks. In a setup where attackers can measure the time of RSA decryption or signature operations, blinding must be used to protect the RSA operation from that attack.

RSA_blinding_on() turns blinding on for key rsa and generates a random blinding factor. ctx is NULL or a pre-allocated and initialized BN_CTX. The random number generator must be seeded prior to calling RSA_blinding_on().

RSA_blinding_off() turns blinding off and frees the memory used for the blinding factor.

### RETURN VALUES

RSA_blinding_on() returns 1 on success, and 0 if an error occurred.

RSA_blinding_off() returns no value.

### SEE ALSO

openssl_rsa(3), openssl_rand(3)

### HISTORY

RSA_blinding_on() and RSA_blinding_off() appeared in SSLeay 0.9.0.