mirror of
https://github.com/cbeuw/Cloak.git
synced 2024-11-11 13:11:03 +00:00
50 lines
1.7 KiB
Go
50 lines
1.7 KiB
Go
package client
|
|
|
|
import (
|
|
"encoding/binary"
|
|
"github.com/cbeuw/Cloak/internal/ecdh"
|
|
"github.com/cbeuw/Cloak/internal/util"
|
|
"io"
|
|
"sync/atomic"
|
|
)
|
|
|
|
const (
|
|
UNORDERED_FLAG = 0x01 // 0000 0001
|
|
)
|
|
|
|
type authenticationPayload struct {
|
|
randPubKey [32]byte
|
|
ciphertextWithTag [64]byte
|
|
}
|
|
|
|
// makeAuthenticationPayload generates the ephemeral key pair, calculates the shared secret, and then compose and
|
|
// encrypt the authenticationPayload
|
|
func makeAuthenticationPayload(sta *State, randReader io.Reader) (ret authenticationPayload, sharedSecret []byte) {
|
|
/*
|
|
Authentication data:
|
|
+----------+----------------+---------------------+-------------+--------------+--------+------------+
|
|
| _UID_ | _Proxy Method_ | _Encryption Method_ | _Timestamp_ | _Session Id_ | _Flag_ | _reserved_ |
|
|
+----------+----------------+---------------------+-------------+--------------+--------+------------+
|
|
| 16 bytes | 12 bytes | 1 byte | 8 bytes | 4 bytes | 1 byte | 6 bytes |
|
|
+----------+----------------+---------------------+-------------+--------------+--------+------------+
|
|
*/
|
|
ephPv, ephPub, _ := ecdh.GenerateKey(randReader)
|
|
copy(ret.randPubKey[:], ecdh.Marshal(ephPub))
|
|
|
|
plaintext := make([]byte, 48)
|
|
copy(plaintext, sta.UID)
|
|
copy(plaintext[16:28], sta.ProxyMethod)
|
|
plaintext[28] = sta.EncryptionMethod
|
|
binary.BigEndian.PutUint64(plaintext[29:37], uint64(sta.Now().Unix()))
|
|
binary.BigEndian.PutUint32(plaintext[37:41], atomic.LoadUint32(&sta.SessionID))
|
|
|
|
if sta.Unordered {
|
|
plaintext[41] |= UNORDERED_FLAG
|
|
}
|
|
|
|
sharedSecret = ecdh.GenerateSharedSecret(ephPv, sta.staticPub)
|
|
ciphertextWithTag, _ := util.AESGCMEncrypt(ret.randPubKey[:12], sharedSecret, plaintext)
|
|
copy(ret.ciphertextWithTag[:], ciphertextWithTag[:])
|
|
return
|
|
}
|