Function deriveSKey

pkg/crypto/key_derivation.go:24–33

deriveSKey derives a session key

(key types.AES128Key, t byte, jn types.JoinNonce, joinEUI types.EUI64, dn types.DevNonce)

// deriveSKey derives a session key
func deriveSKey(key types.AES128Key, t byte, jn types.JoinNonce, joinEUI types.EUI64, dn types.DevNonce) (derived types.AES128Key) {
	buf := make([]byte, 16)
	buf[0] = t
	copy(buf[1:4], reverse(jn[:]))
	copy(buf[4:12], reverse(joinEUI[:]))
	copy(buf[12:14], reverse(dn[:]))
	block, _ := aes.NewCipher(key[:])
	block.Encrypt(derived[:], buf)
	return
}

// deriveLegacySKey derives a session key
func deriveLegacySKey(key types.AES128Key, t byte, jn types.JoinNonce, nid types.NetID, dn types.DevNonce) (derived types.AES128Key) {