RSASignature(String digestName){
  try {
    messageDigest=MessageDigest.getInstance(digestName);
    messageDigestAlgorithm=messageDigest.getAlgorithm();
  }
 catch (  NoSuchAlgorithmException e) {
    throw new ProviderException(e);
  }
  needsReset=false;
}

RSASignature ( String digestName ) { try { messageDigest = MessageDigest . getInstance ( digestName ) ; messageDigestAlgorithm = messageDigest . getAlgorithm ( ) ; } catch ( NoSuchAlgorithmException e ) { throw new ProviderException ( e ) ; } needsReset = false ; }
constructs a new rsasignature . used by subclasses .
