public boolean isDigest(String value){
  if (value == null || value.length() != 32)   return false;
  return (convertHexString(value) != null);
}

public boolean isDigest ( String value ) { if ( value == null || value . length ( ) != 32 ) return false ; return ( convertHexString ( value ) != null ) ; }
checks , if value is a valid digest
