52 lines
1,013 B
Go
52 lines
1,013 B
Go
package obfs
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import (
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"crypto/sha256"
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"math/rand"
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"sync"
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"time"
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)
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// [salt][obfuscated payload]
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const saltLen = 16
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type XPlusObfuscator struct {
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Key []byte
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RandSrc *rand.Rand
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lk sync.Mutex
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}
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func NewXPlusObfuscator(key []byte) *XPlusObfuscator {
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return &XPlusObfuscator{
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Key: key,
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RandSrc: rand.New(rand.NewSource(time.Now().UnixNano())),
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}
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}
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func (x *XPlusObfuscator) Deobfuscate(in []byte, out []byte) int {
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pLen := len(in) - saltLen
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if pLen <= 0 || len(out) < pLen {
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// Invalid
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return 0
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}
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key := sha256.Sum256(append(x.Key, in[:saltLen]...))
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// Deobfuscate the payload
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for i, c := range in[saltLen:] {
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out[i] = c ^ key[i%sha256.Size]
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}
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return pLen
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}
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func (x *XPlusObfuscator) Obfuscate(in []byte, out []byte) int {
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x.lk.Lock()
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_, _ = x.RandSrc.Read(out[:saltLen]) // salt
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x.lk.Unlock()
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// Obfuscate the payload
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key := sha256.Sum256(append(x.Key, out[:saltLen]...))
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for i, c := range in {
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out[i+saltLen] = c ^ key[i%sha256.Size]
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}
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return len(in) + saltLen
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}
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