From 231ede17347a6994f74b1586ce3a2b063abc24fd Mon Sep 17 00:00:00 2001 From: Russ Magee Date: Wed, 10 Oct 2018 21:12:38 -0700 Subject: [PATCH] KYBER768 KEM works. :O --- hkexnet/hkexchan.go | 15 +++---- hkexnet/hkexnet.go | 104 +++++++++++++++++++++++++++++++++++++++----- hkexsh/hkexsh.go | 8 ++-- 3 files changed, 105 insertions(+), 22 deletions(-) diff --git a/hkexnet/hkexchan.go b/hkexnet/hkexchan.go index b475562..543e86e 100644 --- a/hkexnet/hkexchan.go +++ b/hkexnet/hkexchan.go @@ -19,7 +19,6 @@ import ( "fmt" "hash" "log" - "math/big" "golang.org/x/crypto/blowfish" "golang.org/x/crypto/twofish" @@ -33,7 +32,7 @@ import ( /* Support functionality to set up encryption after a channel has been negotiated via hkexnet.go */ -func (hc Conn) getStream(keymat *big.Int) (rc cipher.Stream, mc hash.Hash, err error) { +func (hc Conn) getStream(keymat []byte) (rc cipher.Stream, mc hash.Hash, err error) { var key []byte var block cipher.Block var iv []byte @@ -44,23 +43,23 @@ func (hc Conn) getStream(keymat *big.Int) (rc cipher.Stream, mc hash.Hash, err e // is >= 2*cipher.BlockSize (enough for both key and iv) switch copts { case CAlgAES256: - key = keymat.Bytes()[0:aes.BlockSize] + key = keymat[0:aes.BlockSize] block, err = aes.NewCipher(key) ivlen = aes.BlockSize - iv = keymat.Bytes()[aes.BlockSize : aes.BlockSize+ivlen] + iv = keymat[aes.BlockSize : aes.BlockSize+ivlen] rc = cipher.NewOFB(block, iv) log.Printf("[cipher AES_256 (%d)]\n", copts) break case CAlgTwofish128: - key = keymat.Bytes()[0:twofish.BlockSize] + key = keymat[0:twofish.BlockSize] block, err = twofish.NewCipher(key) ivlen = twofish.BlockSize - iv = keymat.Bytes()[twofish.BlockSize : twofish.BlockSize+ivlen] + iv = keymat[twofish.BlockSize : twofish.BlockSize+ivlen] rc = cipher.NewOFB(block, iv) log.Printf("[cipher TWOFISH_128 (%d)]\n", copts) break case CAlgBlowfish64: - key = keymat.Bytes()[0:blowfish.BlockSize] + key = keymat[0:blowfish.BlockSize] block, err = blowfish.NewCipher(key) ivlen = blowfish.BlockSize // N.b. Bounds enforcement of differing cipher algorithms @@ -72,7 +71,7 @@ func (hc Conn) getStream(keymat *big.Int) (rc cipher.Stream, mc hash.Hash, err e // // I assume the other two check bounds and only // copy what's needed whereas blowfish does no such check. - iv = keymat.Bytes()[blowfish.BlockSize : blowfish.BlockSize+ivlen] + iv = keymat[blowfish.BlockSize : blowfish.BlockSize+ivlen] rc = cipher.NewOFB(block, iv) log.Printf("[cipher BLOWFISH_64 (%d)]\n", copts) break diff --git a/hkexnet/hkexnet.go b/hkexnet/hkexnet.go index 545e2b7..12742b2 100644 --- a/hkexnet/hkexnet.go +++ b/hkexnet/hkexnet.go @@ -46,6 +46,7 @@ import ( "time" "blitter.com/go/hkexsh/herradurakex" + kyber "git.schwanenlied.me/yawning/kyber.git" ) /*---------------------------------------------------------------------*/ @@ -171,12 +172,14 @@ func _new(kexAlg KEXAlg, conn *net.Conn) (hc *Conn, e error) { // Set up KEx/KEM-specifics switch hc.kex { case KEX_HERRADURA: - default: - return hc, HKExAcceptSetup(hc.c, hc) + return hc, nil //HKExAcceptSetup(hc.c, hc) log.Printf("[KEx alg %d accepted]\n", kexAlg) case KEX_KYBER768: - fmt.Println("KYBER768: TODO") - return nil, errors.New("KEx Setup failed") + return hc, nil //Kyber768AcceptSetup(hc.c, hc) + log.Printf("[KEx alg %d accepted]\n", kexAlg) + default: + return hc, nil //HKExAcceptSetup(hc.c, hc) + log.Printf("[KEx alg %d accepted]\n", kexAlg) } return } @@ -222,8 +225,53 @@ func (hc *Conn) applyConnExtensions(extensions ...string) { } } +// randReader wraps rand.Read() in a struct that implements io.Reader +// for use by the Kyber KEM methods. +type randReader struct { +} + +func (r randReader) Read(b []byte) (n int, e error) { + n, e = rand.Read(b) + return +} + func Kyber768DialSetup(c net.Conn, hc *Conn) (err error) { - return errors.New("NOT IMPLEMENTED") + //h := hkex.New(0, 0) + // Send hkexnet.Conn parameters to remote side + + // Alice, step 1: Generate a key pair. + r := new(randReader) + alicePublicKey, alicePrivateKey, err := kyber.Kyber768.GenerateKeyPair(r) + if err != nil { + panic(err) + } + + // Alice, step 2: Send the public key to Bob + fmt.Fprintf(c, "0x%x\n%08x:%08x\n", alicePublicKey.Bytes(), + hc.cipheropts, hc.opts) + + // [Bob, step 1-3], from which we read cipher text + b := big.NewInt(0) + _, err = fmt.Fscanln(c, b) + if err != nil { + return err + } + log.Printf("[Got server ciphertext:0x%x]\n", b.Bytes()) + + // Read cipheropts, session opts + _, err = fmt.Fscanf(c, "%08x:%08x\n", + &hc.cipheropts, &hc.opts) + if err != nil { + return err + } + + // Alice, step 3: Decrypt the KEM cipher text. + aliceSharedSecret := alicePrivateKey.KEMDecrypt(b.Bytes()) + + log.Printf("[Derived sharedSecret:0x%x]\n", aliceSharedSecret) + hc.r, hc.rm, err = hc.getStream(aliceSharedSecret) + hc.w, hc.wm, err = hc.getStream(aliceSharedSecret) + return } func HKExDialSetup(c net.Conn, hc *Conn) (err error) { @@ -251,13 +299,47 @@ func HKExDialSetup(c net.Conn, hc *Conn) (err error) { h.ComputeFA() log.Printf("**(c)** FA:%s\n", h.FA()) - hc.r, hc.rm, err = hc.getStream(h.FA()) - hc.w, hc.wm, err = hc.getStream(h.FA()) + hc.r, hc.rm, err = hc.getStream(h.FA().Bytes()) + hc.w, hc.wm, err = hc.getStream(h.FA().Bytes()) return } func Kyber768AcceptSetup(c *net.Conn, hc *Conn) (err error) { - return errors.New("NOT IMPLEMENTED") + //h := hkex.New(0, 0) + // Bob, step 1: Deserialize Alice's public key from the binary encoding. + alicePublicKey := big.NewInt(0) + _, err = fmt.Fscanln(*c, alicePublicKey) + log.Printf("[Got client pubKey:0x%x\n]", alicePublicKey) + if err != nil { + return err + } + _, err = fmt.Fscanf(*c, "%08x:%08x\n", + &hc.cipheropts, &hc.opts) + log.Printf("[Got cipheropts, opts:%v, %v]", hc.cipheropts, hc.opts) + if err != nil { + return err + } + + peerPublicKey, err := kyber.Kyber768.PublicKeyFromBytes(alicePublicKey.Bytes()) + if err != nil { + panic(err) + } + + // Bob, step 2: Generate the KEM cipher text and shared secret. + r := new(randReader) + cipherText, bobSharedSecret, err := peerPublicKey.KEMEncrypt(r) + if err != nil { + panic(err) + } + + // Bob, step 3: Send the cipher text to Alice (Not shown). + fmt.Fprintf(*c, "0x%x\n%08x:%08x\n", cipherText, + hc.cipheropts, hc.opts) + + log.Printf("[Derived sharedSecret:0x%x]\n", bobSharedSecret) + hc.r, hc.rm, err = hc.getStream(bobSharedSecret) + hc.w, hc.wm, err = hc.getStream(bobSharedSecret) + return } func HKExAcceptSetup(c *net.Conn, hc *Conn) (err error) { @@ -286,8 +368,8 @@ func HKExAcceptSetup(c *net.Conn, hc *Conn) (err error) { fmt.Fprintf(*c, "0x%s\n%08x:%08x\n", h.D().Text(16), hc.cipheropts, hc.opts) - hc.r, hc.rm, err = hc.getStream(h.FA()) - hc.w, hc.wm, err = hc.getStream(h.FA()) + hc.r, hc.rm, err = hc.getStream(h.FA().Bytes()) + hc.w, hc.wm, err = hc.getStream(h.FA().Bytes()) return } @@ -306,7 +388,7 @@ func Dial(protocol string, ipport string, extensions ...string) (hc Conn, err er if err != nil { return Conn{}, err } - + // Init hkexnet.Conn hc over net.Conn c ret, err := _new(getkexalgnum(extensions...), &c) if err != nil { diff --git a/hkexsh/hkexsh.go b/hkexsh/hkexsh.go index af1e1c3..173a097 100755 --- a/hkexsh/hkexsh.go +++ b/hkexsh/hkexsh.go @@ -351,8 +351,9 @@ func main() { var gopt bool //login via password, asking server to generate authToken var dbg bool var shellMode bool // if true act as shell, else file copier - var cAlg string - var hAlg string + var cAlg string //cipher alg + var hAlg string //hmac alg + var kAlg string //KEX/KEM alg var server string var port uint var cmdStr string @@ -373,6 +374,7 @@ func main() { flag.BoolVar(&dbg, "d", false, "debug logging") flag.StringVar(&cAlg, "c", "C_AES_256", "`cipher` [\"C_AES_256\" | \"C_TWOFISH_128\" | \"C_BLOWFISH_64\"]") flag.StringVar(&hAlg, "m", "H_SHA256", "`hmac` [\"H_SHA256\"]") + flag.StringVar(&kAlg, "k", "KEX_HERRADURA", "`kex` [\"KEX_HERRADURA\" | \"KEX_KYBER768\"]") flag.UintVar(&port, "p", 2000, "`port`") //flag.StringVar(&authCookie, "a", "", "auth cookie") flag.BoolVar(&chaffEnabled, "e", true, "enabled chaff pkts (default true)") @@ -543,7 +545,7 @@ func main() { } } - conn, err := hkexnet.Dial("tcp", server, "KEX_HERRADURA", cAlg, hAlg) + conn, err := hkexnet.Dial("tcp", server, cAlg, hAlg, kAlg) if err != nil { fmt.Println(err) panic(err)