}

	left = (left << 31) | (left >> 1)
	right = (right << 31) | (right >> 1)

	preOutput := (uint64(right) << 32) | uint64(left)
	byteorder.BePutUint64(dst, permuteFinalBlock(preOutput))
}

func (c *tripleDESCipher) Decrypt(dst, src []byte) {
	if len(src) < BlockSize {
		panic("crypto/des: input not full block")
	}
	if len(dst) < BlockSize {

	0, 8, 16, 24, 32, 40, 48, 56,
	7, 15, 23, 31, 39, 47, 55, 63,
	5, 13, 21, 29, 37, 45, 53, 61,
	3, 11, 19, 27, 35, 43, 51, 59,
	1, 9, 17, 25, 33, 41, 49, 57,
}

// Used to perform a final permutation of a 4-bit preoutput block. This is the
// inverse of initialPermutation
var finalPermutation = [64]byte{
	24, 56, 16, 48, 8, 40, 0, 32,
	25, 57, 17, 49, 9, 41, 1, 33,
	26, 58, 18, 50, 10, 42, 2, 34,
	27, 59, 19, 51, 11, 43, 3, 35,

		}
	}

	left = (left << 31) | (left >> 1)
	right = (right << 31) | (right >> 1)

	// switch left & right and perform final permutation
	preOutput := (uint64(right) << 32) | uint64(left)
	byteorder.BePutUint64(dst, permuteFinalBlock(preOutput))
}

// DES Feistel function. feistelBox must be initialized via
// feistelBoxOnce.Do(initFeistelBox) first.
func feistel(l, r uint32, k0, k1 uint64) (lout, rout uint32) {