question: RSASignature ( String digestName ) { try { messageDigest = MessageDigest . getInstance ( digestName ) ; messageDigestAlgorithm = messageDigest . getAlgorithm ( ) ; } catch ( NoSuchAlgorithmException e ) { throw new ProviderException ( e ) ; } needsReset = false ; }
target:  Constructs a new RSASignature. Used by subclasses.