Files
mihomo/transport/sudoku/session_keys.go
2026-03-01 10:22:53 +08:00

59 lines
1.7 KiB
Go

package sudoku
import (
"crypto/ecdh"
"crypto/sha256"
"fmt"
"io"
"golang.org/x/crypto/hkdf"
)
func derivePSKDirectionalBases(psk string) (c2s, s2c []byte) {
sum := sha256.Sum256([]byte(psk))
c2sKey := make([]byte, 32)
s2cKey := make([]byte, 32)
if _, err := io.ReadFull(hkdf.Expand(sha256.New, sum[:], []byte("sudoku-psk-c2s")), c2sKey); err != nil {
panic("sudoku: hkdf expand failed")
}
if _, err := io.ReadFull(hkdf.Expand(sha256.New, sum[:], []byte("sudoku-psk-s2c")), s2cKey); err != nil {
panic("sudoku: hkdf expand failed")
}
return c2sKey, s2cKey
}
func deriveSessionDirectionalBases(psk string, shared []byte, nonce [kipHelloNonceSize]byte) (c2s, s2c []byte, err error) {
sum := sha256.Sum256([]byte(psk))
ikm := make([]byte, 0, len(shared)+len(nonce))
ikm = append(ikm, shared...)
ikm = append(ikm, nonce[:]...)
prk := hkdf.Extract(sha256.New, ikm, sum[:])
c2sKey := make([]byte, 32)
s2cKey := make([]byte, 32)
if _, err := io.ReadFull(hkdf.Expand(sha256.New, prk, []byte("sudoku-session-c2s")), c2sKey); err != nil {
return nil, nil, fmt.Errorf("hkdf expand c2s: %w", err)
}
if _, err := io.ReadFull(hkdf.Expand(sha256.New, prk, []byte("sudoku-session-s2c")), s2cKey); err != nil {
return nil, nil, fmt.Errorf("hkdf expand s2c: %w", err)
}
return c2sKey, s2cKey, nil
}
func x25519SharedSecret(priv *ecdh.PrivateKey, peerPub []byte) ([]byte, error) {
if priv == nil {
return nil, fmt.Errorf("nil priv")
}
curve := ecdh.X25519()
pk, err := curve.NewPublicKey(peerPub)
if err != nil {
return nil, fmt.Errorf("parse peer pub: %w", err)
}
secret, err := priv.ECDH(pk)
if err != nil {
return nil, fmt.Errorf("ecdh: %w", err)
}
return secret, nil
}