Clash.Meta/transport/hysteria/obfs/xplus.go
2023-03-06 18:10:14 +08:00

46 lines
890 B
Go

package obfs
import (
"crypto/sha256"
"github.com/zhangyunhao116/fastrand"
)
// [salt][obfuscated payload]
const saltLen = 16
type XPlusObfuscator struct {
Key []byte
}
func NewXPlusObfuscator(key []byte) *XPlusObfuscator {
return &XPlusObfuscator{
Key: key,
}
}
func (x *XPlusObfuscator) Deobfuscate(in []byte, out []byte) int {
pLen := len(in) - saltLen
if pLen <= 0 || len(out) < pLen {
// Invalid
return 0
}
key := sha256.Sum256(append(x.Key, in[:saltLen]...))
// Deobfuscate the payload
for i, c := range in[saltLen:] {
out[i] = c ^ key[i%sha256.Size]
}
return pLen
}
func (x *XPlusObfuscator) Obfuscate(in []byte, out []byte) int {
_, _ = fastrand.Read(out[:saltLen]) // salt
// Obfuscate the payload
key := sha256.Sum256(append(x.Key, out[:saltLen]...))
for i, c := range in {
out[i+saltLen] = c ^ key[i%sha256.Size]
}
return len(in) + saltLen
}