public static function charset( $charset = null ) 
	{	
		switch( $charset ) 
		{	
			case 'pass':
			case 'secure':
			case 'password':
				return static::SECURE;
			break;

			case 'key':
				return static::KEY;
			break;

			case 'alphanum':
				return static::ALPHA_NUM;
			break;

			case 'alpha':
				return static::ALPHA;
			break;

			case 'alpha_low':
			case 'lowercase':
				return static::ALPHA_LOW;
			break;

			case 'alpha_up':
			case 'uppercase':
				return static::ALPHA_UP;
			break;

			case 'numeric':
			case 'num':
				return static::NUM;
			break;

			case 'hex':
				return static::HEX;
			break;

			case 'bin':
				return static::BIN;
			break;

			default:
				if ( !is_null( $charset ) ) 
				{
					return $charset;
				}
				return static::charset( 'alphanum' );
			break;
		}
	}