def pkcs1Digest(data, messageLength):
 digest = sha1(data).digest()
 return pkcs1Pad((ID_SHA1 + digest), messageLength)

def pkcs1Digest ( data , messageLength ) : digest = sha1 ( data ) . digest ( ) return pkcs1Pad ( ( ID_SHA1 + digest ) , messageLength )
create a message digest using the sha1 hash algorithm according to the pkcs#1 standard .