X.509RSA

This signature algorithm will perform "raw" RSA exponentiation on the input message by converting it to an integer (most-significant byte first) and converting the result to a byte string (most-significant byte first). The input message, considered as an integer, must be less than the modulus. Where necessary, the input message is padded by prepending the message with 0-valued bytes.

This algorithm is intended for compatibility with applications that do not follow the PKCS#1 block format.