github.com/fumiama/gofastTEA@v0.0.10/tea_1.16.go

//go:build (!go1.17 && amd64) || !amd64
// +build !go1.17,amd64 !amd64

package tea

import "encoding/binary"

// Encrypt tea 加密
// http://bbs.chinaunix.net/thread-583468-1-1.html
// 感谢xichen大佬对TEA的解释
//go:nosplit
func (t TEA) EncryptLittleEndian(src []byte, sumtable [0x10]uint32) (dst []byte) {
	lens := len(src)
	fill := 10 - (lens+1)&7
	dst = make([]byte, fill+lens+7)
	binary.LittleEndian.PutUint32(dst, randuint32())
	binary.LittleEndian.PutUint32(dst[4:], randuint32())
	binary.LittleEndian.PutUint32(dst[8:], randuint32())
	dst[0] = byte(fill-3) | 0xF8 // 存储pad长度
	copy(dst[fill:], src)

	var iv1, iv2, holder uint64
	var v0, v1 uint32
	for i := 0; i < len(dst); i += 8 {
		holder = binary.LittleEndian.Uint64(dst[i:]) ^ iv1
		v0, v1 = uint32(holder>>32), uint32(holder)
		for i := 0; i < 0x10; i++ {
			v0 += (v1 + sumtable[i]) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
			v1 += (v0 + sumtable[i]) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		}
		iv1 = (uint64(v0)<<32 | uint64(v1)) ^ iv2
		iv2 = holder
		binary.LittleEndian.PutUint64(dst[i:], iv1)
	}

	return dst
}

//go:nosplit
func (t TEA) EncryptLittleEndianTo(src []byte, sumtable [0x10]uint32, dst []byte) int {
	lens := len(src)
	fill := 10 - (lens+1)&7
	binary.LittleEndian.PutUint32(dst, randuint32())
	binary.LittleEndian.PutUint32(dst[4:], randuint32())
	binary.LittleEndian.PutUint32(dst[8:], randuint32())
	dst[0] = byte(fill-3) | 0xF8 // 存储pad长度
	copy(dst[fill:], src)

	var iv1, iv2, holder uint64
	var v0, v1 uint32
	for i := 0; i < fill+lens+7; i += 8 {
		holder = binary.LittleEndian.Uint64(dst[i:]) ^ iv1
		v0, v1 = uint32(holder>>32), uint32(holder)
		for i := 0; i < 0x10; i++ {
			v0 += (v1 + sumtable[i]) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
			v1 += (v0 + sumtable[i]) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		}
		iv1 = (uint64(v0)<<32 | uint64(v1)) ^ iv2
		iv2 = holder
		binary.LittleEndian.PutUint64(dst[i:], iv1)
	}

	return fill + lens + 7
}

//go:nosplit
func (t TEA) Decrypt(data []byte) []byte {
	if len(data) < 16 || len(data)&7 != 0 {
		return nil
	}
	dst := make([]byte, len(data))

	var iv1, iv2, holder uint64
	var v0, v1 uint32
	for i := 0; i < len(dst); i += 8 {
		iv1 = binary.BigEndian.Uint64(data[i:])
		iv2 ^= iv1
		v0, v1 = uint32(iv2>>32), uint32(iv2)
		v1 -= (v0 + 0xe3779b90) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0xe3779b90) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0x454021d7) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0x454021d7) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0xa708a81e) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0xa708a81e) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0x08d12e65) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0x08d12e65) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0x6a99b4ac) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0x6a99b4ac) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0xcc623af3) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0xcc623af3) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0x2e2ac13a) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0x2e2ac13a) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0x8ff34781) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0x8ff34781) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0xf1bbcdc8) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0xf1bbcdc8) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0x5384540f) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0x5384540f) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0xb54cda56) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0xb54cda56) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0x1715609d) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0x1715609d) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0x78dde6e4) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0x78dde6e4) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0xdaa66d2b) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0xdaa66d2b) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0x3c6ef372) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0x3c6ef372) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0x9e3779b9) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0x9e3779b9) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		iv2 = uint64(v0)<<32 | uint64(v1)
		binary.BigEndian.PutUint64(dst[i:], iv2^holder)
		holder = iv1
	}

	return dst[dst[0]&7+3 : len(data)-7]
}

//go:nosplit
func (t TEA) DecryptTo(data []byte, dst []byte) (from, to int) {
	if len(data) < 16 || len(data)&7 != 0 {
		return -1, -1
	}

	var iv1, iv2, holder uint64
	var v0, v1 uint32
	for i := 0; i < len(data); i += 8 {
		iv1 = binary.BigEndian.Uint64(data[i:])
		iv2 ^= iv1
		v0, v1 = uint32(iv2>>32), uint32(iv2)
		v1 -= (v0 + 0xe3779b90) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0xe3779b90) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0x454021d7) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0x454021d7) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0xa708a81e) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0xa708a81e) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0x08d12e65) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0x08d12e65) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0x6a99b4ac) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0x6a99b4ac) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0xcc623af3) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0xcc623af3) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0x2e2ac13a) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0x2e2ac13a) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0x8ff34781) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0x8ff34781) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0xf1bbcdc8) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0xf1bbcdc8) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0x5384540f) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0x5384540f) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0xb54cda56) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0xb54cda56) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0x1715609d) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0x1715609d) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0x78dde6e4) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0x78dde6e4) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0xdaa66d2b) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0xdaa66d2b) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0x3c6ef372) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0x3c6ef372) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		v1 -= (v0 + 0x9e3779b9) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
		v0 -= (v1 + 0x9e3779b9) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		iv2 = uint64(v0)<<32 | uint64(v1)
		binary.BigEndian.PutUint64(dst[i:], iv2^holder)
		holder = iv1
	}

	return int(dst[0]&7 + 3), len(data) - 7
}

//go:nosplit
func (t TEA) DecryptLittleEndian(data []byte, sumtable [0x10]uint32) []byte {
	if len(data) < 16 || len(data)&7 != 0 {
		return nil
	}
	dst := make([]byte, len(data))

	var iv1, iv2, holder uint64
	var v0, v1 uint32
	for i := 0; i < len(dst); i += 8 {
		iv1 = binary.LittleEndian.Uint64(data[i:])
		iv2 ^= iv1
		v0, v1 = uint32(iv2>>32), uint32(iv2)
		for i := 0xf; i >= 0; i-- {
			v1 -= (v0 + sumtable[i]) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
			v0 -= (v1 + sumtable[i]) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		}
		iv2 = uint64(v0)<<32 | uint64(v1)
		binary.LittleEndian.PutUint64(dst[i:], iv2^holder)
		holder = iv1
	}

	return dst[dst[0]&7+3 : len(data)-7]
}

//go:nosplit
func (t TEA) DecryptLittleEndianTo(data []byte, sumtable [0x10]uint32, dst []byte) (from, to int) {
	if len(data) < 16 || len(data)&7 != 0 {
		return -1, -1
	}

	var iv1, iv2, holder uint64
	var v0, v1 uint32
	for i := 0; i < len(data); i += 8 {
		iv1 = binary.LittleEndian.Uint64(data[i:])
		iv2 ^= iv1
		v0, v1 = uint32(iv2>>32), uint32(iv2)
		for i := 0xf; i >= 0; i-- {
			v1 -= (v0 + sumtable[i]) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
			v0 -= (v1 + sumtable[i]) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
		}
		iv2 = uint64(v0)<<32 | uint64(v1)
		binary.LittleEndian.PutUint64(dst[i:], iv2^holder)
		holder = iv1
	}

	return int(dst[0]&7 + 3), len(data) - 7
}