mirror of
https://github.com/fumiama/gofastTEA.git
synced 2026-06-10 19:40:33 +08:00
82 lines
3.2 KiB
Go
82 lines
3.2 KiB
Go
//go:build !go1.17 && amd64
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// +build !go1.17,amd64
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package tea
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import (
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"encoding/binary"
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_ "unsafe" // required by go:linkname
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)
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// Uint32 returns a lock free uint32 value.
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//go:linkname Uint32 runtime.fastrand
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func Uint32() uint32
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// Encrypt tea 加密
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// http://bbs.chinaunix.net/thread-583468-1-1.html
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// 感谢xichen大佬对TEA的解释
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//go:nosplit
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func (t TEA) Decrypt(data []byte) []byte {
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if len(data) < 16 || len(data)&7 != 0 {
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return nil
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}
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dst := make([]byte, len(data))
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var iv1, iv2, holder uint64
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var v0, v1 uint32
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for i := 0; i < len(dst); i += 8 {
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holder = iv1
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iv1 = binary.BigEndian.Uint64(data[i:])
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iv2 ^= iv1
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v0, v1 = uint32(iv2>>32), uint32(iv2)
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v1 -= (v0 + 0xe3779b90) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
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v0 -= (v1 + 0xe3779b90) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
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v1 -= (v0 + 0x454021d7) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
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v0 -= (v1 + 0x454021d7) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
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v1 -= (v0 + 0xa708a81e) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
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v0 -= (v1 + 0xa708a81e) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
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v1 -= (v0 + 0x08d12e65) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
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v0 -= (v1 + 0x08d12e65) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
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v1 -= (v0 + 0x6a99b4ac) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
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v0 -= (v1 + 0x6a99b4ac) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
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v1 -= (v0 + 0xcc623af3) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
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v0 -= (v1 + 0xcc623af3) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
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v1 -= (v0 + 0x2e2ac13a) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
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v0 -= (v1 + 0x2e2ac13a) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
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v1 -= (v0 + 0x8ff34781) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
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v0 -= (v1 + 0x8ff34781) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
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v1 -= (v0 + 0xf1bbcdc8) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
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v0 -= (v1 + 0xf1bbcdc8) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
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v1 -= (v0 + 0x5384540f) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
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v0 -= (v1 + 0x5384540f) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
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v1 -= (v0 + 0xb54cda56) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
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v0 -= (v1 + 0xb54cda56) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
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v1 -= (v0 + 0x1715609d) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
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v0 -= (v1 + 0x1715609d) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
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v1 -= (v0 + 0x78dde6e4) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
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v0 -= (v1 + 0x78dde6e4) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
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v1 -= (v0 + 0xdaa66d2b) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
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v0 -= (v1 + 0xdaa66d2b) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
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v1 -= (v0 + 0x3c6ef372) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
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v0 -= (v1 + 0x3c6ef372) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
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v1 -= (v0 + 0x9e3779b9) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
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v0 -= (v1 + 0x9e3779b9) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
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iv2 = uint64(v0)<<32 | uint64(v1)
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binary.BigEndian.PutUint64(dst[i:], iv2^holder)
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}
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return dst[dst[0]&7+3 : len(data)-7]
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}
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//go:nosplit
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func NewTeaCipher(key []byte) (t TEA) {
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if len(key) == 16 {
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t[3] = binary.BigEndian.Uint32(key[12:])
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t[2] = binary.BigEndian.Uint32(key[8:])
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t[1] = binary.BigEndian.Uint32(key[4:])
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t[0] = binary.BigEndian.Uint32(key[0:])
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}
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return
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}
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