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sidh: updates (#31)

pull/32/head
Henry Case 4 years ago
committed by GitHub
parent
f5a7daf2bb
commit
bc32024729
No known key found for this signature in database GPG Key ID: 4AEE18F83AFDEB23
10 changed files with 90 additions and 663 deletions
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  1. +5
    -11
      Makefile
  2. +1
    -0
      dh/sidh/internal/doc.go
  3. +1
    -1
      dh/sidh/internal/p434/arith_amd64_test.go
  4. +1
    -0
      dh/sidh/internal/p434/doc.go
  5. +16
    -10
      dh/sidh/sidh_test.go
  6. +3
    -3
      dh/sidh/sike.go
  7. +61
    -39
      dh/sidh/sike_test.go
  8. +2
    -4
      go.mod
  9. +0
    -217
      kem/sike/sike.go
  10. +0
    -378
      kem/sike/sike_test.go

+ 5
- 11
Makefile View File

@@ -29,15 +29,9 @@ ifeq ($(DBG),1)
OPTS_ENV+= GOTRACEBACK=crash # enable core dumps
endif

test:
test:
$(OPTS_ENV) $(GO) test $(OPTS) $(TEST_PATH)

test_csidh: clean make_dirs $(addprefix prep-,$(TARGETS))
cd $(GOPATH_LOCAL); $(OPTS_ENV) GOPATH=$(GOPATH_LOCAL) go test $(OPTS) github.com/henrydcase/nobs/dh/csidh

test_csidh_bin: clean make_dirs $(addprefix prep-,$(TARGETS))
cd $(GOPATH_LOCAL); $(OPTS_ENV) GOPATH=$(GOPATH_LOCAL) go test -c $(OPTS) github.com/henrydcase/nobs/dh/csidh

cover:
$(GO) test \
-coverprofile=coverage.txt -covermode=atomic $(OPTS) $(TEST_PATH)
@@ -45,10 +39,6 @@ cover:
bench:
$(GO) test $(BENCH_OPTS) $(TEST_PATH)

bench_csidh: clean $(addprefix prep-,$(TARGETS))
cd $(GOPATH_LOCAL); GOCACHE=$(GOCACHE) GOPATH=$(GOPATH_LOCAL) $(GO) test \
$(BENCH_OPTS) github.com/henrydcase/nobs/dh/csidh
clean:
rm -rf $(VENDOR_DIR)
rm -rf coverage.txt
@@ -58,6 +48,10 @@ vendor-sidh-for-tls: clean
rsync -a . $(VENDOR_DIR)/github_com/henrydcase/nobs/ --exclude=$(VENDOR_DIR) --exclude=.git --exclude=.travis.yml --exclude=README.md
find $(VENDOR_DIR) -type f -print0 -name "*.go" | xargs -0 sed -i 's/github\.com/github_com/g'

gen: clean
$(GO) generate -v ./...
$(GO) mod tidy

pprof-cpu:
$(GO) tool pprof cpu.out



+ 1
- 0
dh/sidh/internal/doc.go View File

@@ -0,0 +1 @@
package sidh

+ 1
- 1
dh/sidh/internal/p434/arith_amd64_test.go View File

@@ -10,7 +10,7 @@ import (
"testing"
"testing/quick"

"github.com/henrydcase/nobs/sidh/internal/common"
"github.com/henrydcase/nobs/dh/sidh/internal/common"
"golang.org/x/sys/cpu"
)



+ 1
- 0
dh/sidh/internal/p434/doc.go View File

@@ -0,0 +1 @@
package p434

+ 16
- 10
dh/sidh/sidh_test.go View File

@@ -9,7 +9,6 @@ import (
"testing"

"github.com/henrydcase/nobs/dh/sidh/internal/common"
. "github.com/henrydcase/nobs/internal/test"
)

/* -------------------------------------------------------------------------
@@ -24,6 +23,13 @@ type sidhVec struct {
PrB string
}

func checkErr(t testing.TB, err error, msg string) {
t.Helper()
if err != nil {
t.Error(msg)
}
}

var tdataSidh = map[uint8]sidhVec{
Fp434: {
id: Fp434,
@@ -203,9 +209,9 @@ func testRoundtrip(t *testing.T, v sidhVec) {

// Generate private keys
err = prvA.Generate(rand.Reader)
CheckNoErr(t, err, "key generation failed")
checkErr(t, err, "key generation failed")
err = prvB.Generate(rand.Reader)
CheckNoErr(t, err, "key generation failed")
checkErr(t, err, "key generation failed")

// Generate public keys
prvA.GeneratePublicKey(pubA)
@@ -241,11 +247,11 @@ func testKeyAgreement(t *testing.T, v sidhVec) {

// Negative case
dec, err := hex.DecodeString(v.PkA)
CheckNoErr(t, err, "decoding failed")
checkErr(t, err, "decoding failed")

dec[0] = ^dec[0]
err = alicePublic.Import(dec)
CheckNoErr(t, err, "import failed")
checkErr(t, err, "import failed")

bobPrivate.DeriveSecret(s1, alicePublic)
alicePrivate.DeriveSecret(s2, bobPublic)
@@ -261,16 +267,16 @@ func testImportExport(t *testing.T, v sidhVec) {

// Import keys
aHex, err := hex.DecodeString(v.PkA)
CheckNoErr(t, err, "invalid hex-number provided")
checkErr(t, err, "invalid hex-number provided")

err = a.Import(aHex)
CheckNoErr(t, err, "import failed")
checkErr(t, err, "import failed")

bHex, err := hex.DecodeString(v.PkB)
CheckNoErr(t, err, "invalid hex-number provided")
checkErr(t, err, "invalid hex-number provided")

err = b.Import(bHex)
CheckNoErr(t, err, "import failed")
checkErr(t, err, "import failed")

aBytes := make([]byte, a.Size())
bBytes := make([]byte, b.Size())
@@ -313,7 +319,7 @@ func testPrivateKeyBelowMax(t *testing.T, vec sidhVec) {
// Do same test 1000 times
for i := 0; i < 1000; i++ {
err := prv.Generate(rand.Reader)
CheckNoErr(t, err, "Private key generation")
checkErr(t, err, "Private key generation")

// Convert to big-endian, as that's what expected by (*Int)SetBytes()
prv.Export(secretBytes)


+ 3
- 3
dh/sidh/sike.go View File

@@ -6,7 +6,7 @@ import (
"io"

"github.com/henrydcase/nobs/dh/sidh/internal/common"
"github.com/henrydcase/nobs/internal/shake"
"github.com/henrydcase/nobs/hash/sha3"
)

// SIKE KEM interface.
@@ -16,7 +16,7 @@ type KEM struct {
msg []byte
secretBytes []byte
params *common.SidhParams
shake shake.Shake
shake sha3.ShakeHash
}

// NewSike434 instantiates SIKE/p434 KEM.
@@ -47,7 +47,7 @@ func (c *KEM) Allocate(id uint8, rng io.Reader) {
c.params = common.Params(id)
c.msg = make([]byte, c.params.MsgLen)
c.secretBytes = make([]byte, c.params.A.SecretByteLen)
c.shake = shake.NewShake256()
c.shake = sha3.NewShake256()
c.allocated = true
}



+ 61
- 39
dh/sidh/sike_test.go View File

@@ -5,6 +5,7 @@ import (
"bytes"
"crypto/rand"
"encoding/hex"
"errors"
"fmt"
"io"
"os"
@@ -12,7 +13,6 @@ import (
"testing"

"github.com/henrydcase/nobs/dh/sidh/internal/common"
. "github.com/henrydcase/nobs/internal/test"
)

type sikeVec struct {
@@ -24,6 +24,25 @@ type sikeVec struct {
PrB string
}

func Ok(t testing.TB, err error, msg string) {
t.Helper()
if err != nil {
t.Error(msg)
}
}

// testPanic returns true if call to function 'f' caused panic.
func testPanic(f func()) error {
var hasPanicked = errors.New("no panic detected")
defer func() {
if r := recover(); r != nil {
hasPanicked = nil
}
}()
f()
return hasPanicked
}

var tdataSike = map[uint8]sikeVec{
Fp434: {
Fp434, "P-434", NewSike434(rand.Reader),
@@ -99,17 +118,17 @@ func testPKERoundTrip(t *testing.T, v sikeVec) {
pkB := NewPublicKey(params.ID, KeyVariantSike)
skB := NewPrivateKey(params.ID, KeyVariantSike)
pkHex, err := hex.DecodeString(v.PkB)
CheckNoErr(t, err, "Test vector wrong")
Ok(t, err, "Test vector wrong")
skHex, err := hex.DecodeString(v.PrB)
CheckNoErr(t, err, "Test vector wrong")
Ok(t, err, "Test vector wrong")
err = pkB.Import(pkHex)
CheckNoErr(t, err, "Public key import failed")
Ok(t, err, "Public key import failed")
err = skB.Import(skHex)
CheckNoErr(t, err, "Private key import failed")
Ok(t, err, "Private key import failed")
err = v.kem.encrypt(ct, rand.Reader, pkB, msg[:])
CheckNoErr(t, err, "PKE roundtrip - encryption failed")
Ok(t, err, "PKE roundtrip - encryption failed")
ptLen, err := v.kem.decrypt(pt[:], skB, ct)
CheckNoErr(t, err, "PKE roundtrip - decription failed")
Ok(t, err, "PKE roundtrip - decription failed")

if !bytes.Equal(pt[:ptLen], msg[:]) {
t.Errorf("Decryption failed \n got : %X\n exp : %X", pt[:ptLen], msg)
@@ -132,13 +151,13 @@ func testPKEKeyGeneration(t *testing.T, v sikeVec) {
}

err = sk.Generate(rand.Reader)
CheckNoErr(t, err, "PKE key generation")
Ok(t, err, "PKE key generation")
sk.GeneratePublicKey(pk)

err = v.kem.encrypt(ct, rand.Reader, pk, msg[:])
CheckNoErr(t, err, "PKE encryption")
Ok(t, err, "PKE encryption")
ptLen, err := v.kem.decrypt(pt[:], sk, ct)
CheckNoErr(t, err, "PKE key decryption")
Ok(t, err, "PKE key decryption")

if !bytes.Equal(pt[:ptLen], msg[:]) {
t.Fatalf("Decryption failed \n got : %X\n exp : %X", pt, msg)
@@ -154,12 +173,15 @@ func testNegativePKE(t *testing.T, v sikeVec) {

// Generate key
err = sk.Generate(rand.Reader)
CheckNoErr(t, err, "key generation")
Ok(t, err, "key generation")
sk.GeneratePublicKey(pk)

// bytelen(msg) - 1
err = v.kem.encrypt(ct, rand.Reader, pk, msg[:v.kem.params.KemSize+8-1])
CheckIsErr(t, err, "PKE encryption doesn't fail")
if err == nil {
t.Error(msg)
}

for _, v := range ct {
if v != 0 {
t.Fatal("Returned ciphertext must be not changed")
@@ -178,16 +200,16 @@ func testKEMRoundTrip(t *testing.T, pkB, skB []byte, v sikeVec) {
var ssBsz = v.kem.SharedSecretSize()

err = pk.Import(pkB)
CheckNoErr(t, err, "Public key import failed")
Ok(t, err, "Public key import failed")
err = sk.Import(skB)
CheckNoErr(t, err, "Private key import failed")
Ok(t, err, "Private key import failed")

v.kem.Reset()
err = v.kem.Encapsulate(ct, ssE[:], pk)
CheckNoErr(t, err, "Encapsulation failed")
Ok(t, err, "Encapsulation failed")
v.kem.Reset()
err = v.kem.Decapsulate(ssD[:ssBsz], sk, pk, ct)
CheckNoErr(t, err, "Decapsulation failed")
Ok(t, err, "Decapsulation failed")

if !bytes.Equal(ssE[:v.kem.SharedSecretSize()], ssD[:v.kem.SharedSecretSize()]) {
t.Errorf("Shared secrets from decapsulation and encapsulation differ [%s]", v.name)
@@ -201,16 +223,16 @@ func testKEMKeyGeneration(t *testing.T, v sikeVec) {

sk := NewPrivateKey(v.id, KeyVariantSike)
pk := NewPublicKey(v.id, KeyVariantSike)
CheckNoErr(t, sk.Generate(rand.Reader), "error: key generation")
Ok(t, sk.Generate(rand.Reader), "error: key generation")
sk.GeneratePublicKey(pk)

// calculated shared secret
v.kem.Reset()
err := v.kem.Encapsulate(ct, ssE[:], pk)
CheckNoErr(t, err, "encapsulation failed")
Ok(t, err, "encapsulation failed")
v.kem.Reset()
err = v.kem.Decapsulate(ssD[:v.kem.SharedSecretSize()], sk, pk, ct)
CheckNoErr(t, err, "decapsulation failed")
Ok(t, err, "decapsulation failed")

if !bytes.Equal(ssE[:], ssD[:]) {
t.Fatalf("KEM failed \n encapsulated: %X\n decapsulated: %X", ssD[:], ssE[:])
@@ -226,33 +248,33 @@ func testNegativeKEM(t *testing.T, v sikeVec) {

sk := NewPrivateKey(v.id, KeyVariantSike)
pk := NewPublicKey(v.id, KeyVariantSike)
CheckNoErr(t, sk.Generate(rand.Reader), "error: key generation")
Ok(t, sk.Generate(rand.Reader), "error: key generation")
sk.GeneratePublicKey(pk)

v.kem.Reset()
err := v.kem.Encapsulate(ct, ssE[:], pk)
CheckNoErr(t, err, "pre-requisite for a test failed")
Ok(t, err, "pre-requisite for a test failed")

// Try decapsulate too small ciphertext
v.kem.Reset()
CheckNoErr(
Ok(
t,
CheckPanic(func() { _ = v.kem.Decapsulate(ssTmp[:ssBsz], sk, pk, ct[:len(ct)-2]) }),
testPanic(func() { _ = v.kem.Decapsulate(ssTmp[:ssBsz], sk, pk, ct[:len(ct)-2]) }),
"Decapsulation must panic if ciphertext is too small")

ctTmp := make([]byte, len(ct)+1)
// Try decapsulate too big ciphertext
v.kem.Reset()
CheckNoErr(
Ok(
t,
CheckPanic(func() { _ = v.kem.Decapsulate(ssTmp[:ssBsz], sk, pk, ctTmp) }),
testPanic(func() { _ = v.kem.Decapsulate(ssTmp[:ssBsz], sk, pk, ctTmp) }),
"Decapsulation must panic if ciphertext is too big")

// Change ciphertext
ct[0] = ct[0] - 1
v.kem.Reset()
err = v.kem.Decapsulate(ssD[:ssBsz], sk, pk, ct)
CheckNoErr(t, err, "decapsulation returns error when invalid ciphertext provided")
Ok(t, err, "decapsulation returns error when invalid ciphertext provided")

if bytes.Equal(ssE[:], ssD[:]) {
// no idea how this could ever happen, but it would be very bad
@@ -263,16 +285,16 @@ func testNegativeKEM(t *testing.T, v sikeVec) {
pkSidh := NewPublicKey(v.id, KeyVariantSidhB)
prSidh := NewPrivateKey(v.id, KeyVariantSidhB)
v.kem.Reset()
CheckNoErr(
Ok(
t,
CheckPanic(func() { _ = v.kem.Encapsulate(ct, ssE[:], pkSidh) }),
testPanic(func() { _ = v.kem.Encapsulate(ct, ssE[:], pkSidh) }),
"encapsulation accepts SIDH public key")

// Try decapsulating with SIDH key
v.kem.Reset()
CheckNoErr(
Ok(
t,
CheckPanic(func() { _ = v.kem.Decapsulate(ssD[:ssBsz], prSidh, pk, ct) }),
testPanic(func() { _ = v.kem.Decapsulate(ssD[:ssBsz], prSidh, pk, ct) }),
"encapsulation accepts SIDH public key")
}

@@ -287,18 +309,18 @@ func testNegativeKEMSameWrongResult(t *testing.T, v sikeVec) {

sk := NewPrivateKey(v.id, KeyVariantSike)
pk := NewPublicKey(v.id, KeyVariantSike)
CheckNoErr(t, sk.Generate(rand.Reader), "error: key generation")
Ok(t, sk.Generate(rand.Reader), "error: key generation")
sk.GeneratePublicKey(pk)

v.kem.Reset()
err := v.kem.Encapsulate(ct, ssE[:], pk)
CheckNoErr(t, err, "pre-requisite for a test failed")
Ok(t, err, "pre-requisite for a test failed")

// make ciphertext wrong
ct[0] = ct[0] - 1
v.kem.Reset()
err = v.kem.Decapsulate(ssD1[:ssBsz], sk, pk, ct)
CheckNoErr(t, err, "pre-requisite for a test failed")
Ok(t, err, "pre-requisite for a test failed")

// change secret keysecond decapsulation must be done with same, but imported private key
var expSk [common.MaxSikePrivateKeyBsz]byte
@@ -306,12 +328,12 @@ func testNegativeKEMSameWrongResult(t *testing.T, v sikeVec) {

// create new private key
sk = NewPrivateKey(v.id, KeyVariantSike)
CheckNoErr(t, sk.Import(expSk[:sk.Size()]), "import failed")
Ok(t, sk.Import(expSk[:sk.Size()]), "import failed")

// try decapsulating again.
v.kem.Reset()
err = v.kem.Decapsulate(ssD2[:ssBsz], sk, pk, ct)
CheckNoErr(t, err, "pre-requisite for a test failed")
Ok(t, err, "pre-requisite for a test failed")

// ssD1 must be same as ssD2
if !bytes.Equal(ssD1[:], ssD2[:]) {
@@ -335,7 +357,7 @@ func testKAT(t *testing.T, v sikeVec) {
}

err := v.kem.Decapsulate(ssGot, prvKey, pubKey, ct)
CheckNoErr(t, err, "sike test: can't perform degcapsulation KAT")
Ok(t, err, "sike test: can't perform degcapsulation KAT")
if !bytes.Equal(ssGot, ssExpected) {
t.Fatalf("KAT decapsulation failed\n")
}
@@ -365,7 +387,7 @@ func testKAT(t *testing.T, v sikeVec) {
var prvKey = NewPrivateKey(v.id, KeyVariantSike)
var pubKey = NewPublicKey(v.id, KeyVariantSike)
var pubKeyBytes = make([]byte, pubKey.Size())
CheckNoErr(t, prvKey.Import(sk), "Can't load KAT")
Ok(t, prvKey.Import(sk), "Can't load KAT")

// Generate public key
prvKey.GeneratePublicKey(pubKey)
@@ -439,9 +461,9 @@ func TestKEMRoundTrip(t *testing.T) {
for _, val := range tdataSike {
// fmt.Printf("\tTesting: %s\n", val.name)
pk, err := hex.DecodeString(val.PkB)
CheckNoErr(t, err, "public key B not a number")
Ok(t, err, "public key B not a number")
sk, err := hex.DecodeString(val.PrB)
CheckNoErr(t, err, "private key B not a number")
Ok(t, err, "private key B not a number")
testKEMRoundTrip(t, pk, sk, val)
}
}


+ 2
- 4
go.mod View File

@@ -1,7 +1,5 @@
module github.com/henrydcase/nobs

go 1.14
go 1.12

require (
golang.org/x/sys v0.0.0-20191120155948-bd437916bb0e
)
require golang.org/x/sys v0.0.0-20191120155948-bd437916bb0e

+ 0
- 217
kem/sike/sike.go View File

@@ -1,217 +0,0 @@
// [SIKE] http://www.sike.org/files/SIDH-spec.pdf
// [REF] https://github.com/Microsoft/PQCrypto-SIDH
package sike

import (
"crypto/subtle"
"errors"
"io"
// TODO: Use implementation from xcrypto, once PR below merged
// https://go-review.googlesource.com/c/crypto/+/111281/
. "github.com/henrydcase/nobs/dh/sidh"
cshake "github.com/henrydcase/nobs/hash/sha3"
)

// Constants used for cSHAKE customization
// Those values are different than in [SIKE] - they are encoded on 16bits. This is
// done in order for implementation to be compatible with [REF] and test vectors.
var G = []byte{0x00, 0x00}
var H = []byte{0x01, 0x00}
var F = []byte{0x02, 0x00}

// Generates cShake-256 sum
func cshakeSum(out, in, S []byte) {
h := cshake.NewCShake256(nil, S)
h.Write(in)
h.Read(out)
}

func encrypt(skA *PrivateKey, pkA, pkB *PublicKey, ptext []byte) ([]byte, error) {
var n [40]byte // n can is max 320-bit (see 1.4 of [SIKE])
var ptextLen = len(ptext)

if pkB.Variant() != KeyVariant_SIKE {
return nil, errors.New("wrong key type")
}

j, err := DeriveSecret(skA, pkB)
if err != nil {
return nil, err
}

cshakeSum(n[:ptextLen], j, F)
for i, _ := range ptext {
n[i] ^= ptext[i]
}

ret := make([]byte, pkA.Size()+ptextLen)
copy(ret, pkA.Export())
copy(ret[pkA.Size():], n[:ptextLen])
return ret, nil
}

// -----------------------------------------------------------------------------
// PKE interface
//

// Uses SIKE public key to encrypt plaintext. Requires cryptographically secure PRNG
// Returns ciphertext in case encryption succeeds. Returns error in case PRNG fails
// or wrongly formated input was provided.
func Encrypt(rng io.Reader, pub *PublicKey, ptext []byte) ([]byte, error) {
var params = pub.Params()
var ptextLen = uint(len(ptext))
// c1 must be security level + 64 bits (see [SIKE] 1.4 and 4.3.3)
if ptextLen != (params.KemSize + 8) {
return nil, errors.New("Unsupported message length")
}

skA := NewPrivateKey(params.Id, KeyVariant_SIDH_A)
err := skA.Generate(rng)
if err != nil {
return nil, err
}

pkA := skA.GeneratePublicKey()
return encrypt(skA, pkA, pub, ptext)
}

// Uses SIKE private key to decrypt ciphertext. Returns plaintext in case
// decryption succeeds or error in case unexptected input was provided.
// Constant time
func Decrypt(prv *PrivateKey, ctext []byte) ([]byte, error) {
var params = prv.Params()
var n [40]byte // n can is max 320-bit (see 1.4 of [SIKE])
var c1_len int
var pk_len = params.PublicKeySize

if prv.Variant() != KeyVariant_SIKE {
return nil, errors.New("wrong key type")
}

// ctext is a concatenation of (pubkey_A || c1=ciphertext)
// it must be security level + 64 bits (see [SIKE] 1.4 and 4.3.3)
c1_len = len(ctext) - pk_len
if c1_len != (int(params.KemSize) + 8) {
return nil, errors.New("wrong size of cipher text")
}

c0 := NewPublicKey(params.Id, KeyVariant_SIDH_A)
err := c0.Import(ctext[:pk_len])
if err != nil {
return nil, err
}
j, err := DeriveSecret(prv, c0)
if err != nil {
return nil, err
}

cshakeSum(n[:c1_len], j, F)
for i, _ := range n[:c1_len] {
n[i] ^= ctext[pk_len+i]
}

return n[:c1_len], nil
}

// -----------------------------------------------------------------------------
// KEM interface
//

// Encapsulation receives the public key and generates SIKE ciphertext and shared secret.
// The generated ciphertext is used for authentication.
// The rng must be cryptographically secure PRNG.
// Error is returned in case PRNG fails or wrongly formated input was provided.
func Encapsulate(rng io.Reader, pub *PublicKey) (ctext []byte, secret []byte, err error) {
var params = pub.Params()
// Buffer for random, secret message
var ptext = make([]byte, params.MsgLen)
// r = G(ptext||pub)
var r = make([]byte, params.A.SecretByteLen)
// Resulting shared secret
secret = make([]byte, params.KemSize)

// Generate ephemeral value
_, err = io.ReadFull(rng, ptext)
if err != nil {
return nil, nil, err
}

h := cshake.NewCShake256(nil, G)
h.Write(ptext)
h.Write(pub.Export())
h.Read(r)

// cSHAKE256 implementation is byte oriented. Ensure bitlength is not bigger then to 2^e2-1
r[len(r)-1] &= (1 << (params.A.SecretBitLen % 8)) - 1

// (c0 || c1) = Enc(pkA, ptext; r)
skA := NewPrivateKey(params.Id, KeyVariant_SIDH_A)
err = skA.Import(r)
if err != nil {
return nil, nil, err
}

pkA := skA.GeneratePublicKey()
ctext, err = encrypt(skA, pkA, pub, ptext)
if err != nil {
return nil, nil, err
}

// K = H(ptext||(c0||c1))
h = cshake.NewCShake256(nil, H)
h.Write(ptext)
h.Write(ctext)
h.Read(secret)

return ctext, secret, nil
}

// Decapsulate given the keypair and ciphertext as inputs, Decapsulate outputs a shared
// secret if plaintext verifies correctly, otherwise function outputs random value.
// Decapsulation may fail in case input is wrongly formated.
// Constant time for properly initialized input.
func Decapsulate(prv *PrivateKey, pub *PublicKey, ctext []byte) ([]byte, error) {
var params = pub.Params()
var r = make([]byte, params.A.SecretByteLen)
// Resulting shared secret
var secret = make([]byte, params.KemSize)
var skA = NewPrivateKey(params.Id, KeyVariant_SIDH_A)

m, err := Decrypt(prv, ctext)
if err != nil {
return nil, err
}

// r' = G(m'||pub)
h := cshake.NewCShake256(nil, G)
h.Write(m)
h.Write(pub.Export())
h.Read(r)

// cSHAKE256 implementation is byte oriented: Ensure bitlength is not bigger than 2^e2-1
r[len(r)-1] &= (1 << (params.A.SecretBitLen % 8)) - 1

// Never fails
skA.Import(r)

// Never fails
pkA := skA.GeneratePublicKey()
c0 := pkA.Export()

h = cshake.NewCShake256(nil, H)
if subtle.ConstantTimeCompare(c0, ctext[:len(c0)]) == 1 {
h.Write(m)
} else {
// S is chosen at random when generating a key and unknown to other party. It
// may seem weird, but it's correct. It is important that S is unpredictable
// to other party. Without this check, it is possible to recover a secret, by
// providing series of invalid ciphertexts. It is also important that in case
//
// See more details in "On the security of supersingular isogeny cryptosystems"
// (S. Galbraith, et al., 2016, ePrint #859).
h.Write(prv.S)
}
h.Write(ctext)
h.Read(secret)
return secret, nil
}

+ 0
- 378
kem/sike/sike_test.go View File

@@ -1,378 +0,0 @@
package sike

import (
"testing"

"bufio"
"bytes"
"encoding/hex"
"io"
"os"
"strings"

"fmt"

rand "crypto/rand"
. "github.com/henrydcase/nobs/dh/sidh"
)

const (
Pk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
PrB = "00010203040506070809000102030405060708090001020304050607080901028626ED79D451140800E03B59B956F8210E556067407D13DC90FA9E8B872BFB8FAB0A7289852106E40538D3575C500201"
)

var params = Params(FP_751)

type MultiIdTestingFunc func(*testing.T, uint8)

func Do(f MultiIdTestingFunc, t *testing.T) {
for id, val := range tdata {
params = Params(id)
fmt.Printf("\tTesting: %s\n", val.name)
f(t, id)
}
}

var tdata = map[uint8]struct {
name string
KatFile string
PkB string
PrB string
}{
FP_503: {
"P-503",
"../../etc/PQCkemKAT_434.rsp",
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
"9BC5315580207C6C16DCF3A30C48DAF278DE12E8C27DF6735A4D0A8A41C4F666854E9B13673071CEB2FD61DEF9A850C211E7C50071B1DD0D"},
FP_751: {
"P-751",
"../../etc/PQCkemKAT_644.rsp",
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
"00010203040506070809000102030405060708090001020304050607080901028626ED79D451140800E03B59B956F8210E556067407D13DC90FA9E8B872BFB8FAB0A7289852106E40538D3575C500201"},
}

// Fail if err !=nil. Display msg as an error message
func checkErr(t testing.TB, err error, msg string) {
if err != nil {
t.Errorf("%s [%s]", msg, err)
}
}

// Encrypt, Decrypt, check if input/output plaintext is the same
func testPKERoundTrip(t *testing.T, id uint8) {
// Message to be encrypted
var params = Params(id)
var msg = make([]byte, params.MsgLen)
for i, _ := range msg {
msg[i] = byte(i)
}

// Import keys
pkB := NewPublicKey(params.Id, KeyVariant_SIKE)
skB := NewPrivateKey(params.Id, KeyVariant_SIKE)
pk_hex, err := hex.DecodeString(tdata[id].PkB)
if err != nil {
t.Fatal(err)
}
sk_hex, err := hex.DecodeString(tdata[id].PrB)
if err != nil {
t.Fatal(err)
}
if pkB.Import(pk_hex) != nil || skB.Import(sk_hex) != nil {
t.Error("Import")
}

ct, err := Encrypt(rand.Reader, pkB, msg[:])
if err != nil {
t.Fatal(err)
}
pt, err := Decrypt(skB, ct)
if err != nil {
t.Fatal(err)
}
if !bytes.Equal(pt[:], msg[:]) {
t.Errorf("Decryption failed \n got : %X\n exp : %X", pt, msg)
}
}

// Generate key and check if can encrypt
func testPKEKeyGeneration(t *testing.T, id uint8) {
// Message to be encrypted
var params = Params(id)
var msg = make([]byte, params.MsgLen)
var err error
for i, _ := range msg {
msg[i] = byte(i)
}

sk := NewPrivateKey(id, KeyVariant_SIKE)
err = sk.Generate(rand.Reader)
checkErr(t, err, "PEK key generation")
pk := sk.GeneratePublicKey()

// Try to encrypt
ct, err := Encrypt(rand.Reader, pk, msg[:])
checkErr(t, err, "PEK encryption")
pt, err := Decrypt(sk, ct)
checkErr(t, err, "PEK key decryption")

if !bytes.Equal(pt[:], msg[:]) {
t.Fatalf("Decryption failed \n got : %X\n exp : %X", pt, msg)
}
}

func testNegativePKE(t *testing.T, id uint8) {
var msg [40]byte
var err error
var params = Params(id)

// Generate key
sk := NewPrivateKey(params.Id, KeyVariant_SIKE)
err = sk.Generate(rand.Reader)
checkErr(t, err, "key generation")

pk := sk.GeneratePublicKey()

// bytelen(msg) - 1
ct, err := Encrypt(rand.Reader, pk, msg[:params.KemSize+8-1])
if err == nil {
t.Fatal("Error hasn't been returned")
}
if ct != nil {
t.Fatal("Ciphertext must be nil")
}

// KemSize - 1
pt, err := Decrypt(sk, msg[:params.KemSize+8-1])
if err == nil {
t.Fatal("Error hasn't been returned")
}
if pt != nil {
t.Fatal("Ciphertext must be nil")
}
}

func testKEMRoundTrip(t *testing.T, pkB, skB []byte, id uint8) {
// Import keys
pk := NewPublicKey(id, KeyVariant_SIKE)
sk := NewPrivateKey(id, KeyVariant_SIKE)
if pk.Import(pkB) != nil || sk.Import(skB) != nil {
t.Error("Import failed")
}

ct, ss_e, err := Encapsulate(rand.Reader, pk)
if err != nil {
t.Error("Encapsulate failed")
}

ss_d, err := Decapsulate(sk, pk, ct)
if err != nil {
t.Error("Decapsulate failed")
}
if !bytes.Equal(ss_e, ss_d) {
t.Error("Shared secrets from decapsulation and encapsulation differ")
}
}

func TestKEMRoundTrip(t *testing.T) {
for id, val := range tdata {
fmt.Printf("\tTesting: %s\n", val.name)
pk, err := hex.DecodeString(tdata[id].PkB)
checkErr(t, err, "public key B not a number")
sk, err := hex.DecodeString(tdata[id].PrB)
checkErr(t, err, "private key B not a number")
testKEMRoundTrip(t, pk, sk, id)
}
}

func testKEMKeyGeneration(t *testing.T, id uint8) {
// Generate key
sk := NewPrivateKey(id, KeyVariant_SIKE)
checkErr(t, sk.Generate(rand.Reader), "error: key generation")
pk := sk.GeneratePublicKey()

// calculated shared secret
ct, ss_e, err := Encapsulate(rand.Reader, pk)
checkErr(t, err, "encapsulation failed")
ss_d, err := Decapsulate(sk, pk, ct)
checkErr(t, err, "decapsulation failed")

if !bytes.Equal(ss_e, ss_d) {
t.Fatalf("KEM failed \n encapsulated: %X\n decapsulated: %X", ss_d, ss_e)
}
}

func testNegativeKEM(t *testing.T, id uint8) {
sk := NewPrivateKey(id, KeyVariant_SIKE)
checkErr(t, sk.Generate(rand.Reader), "error: key generation")
pk := sk.GeneratePublicKey()

ct, ss_e, err := Encapsulate(rand.Reader, pk)
checkErr(t, err, "pre-requisite for a test failed")

ct[0] = ct[0] - 1
ss_d, err := Decapsulate(sk, pk, ct)
checkErr(t, err, "decapsulation returns error when invalid ciphertext provided")

if bytes.Equal(ss_e, ss_d) {
// no idea how this could ever happen, but it would be very bad
t.Error("critical error")
}

// Try encapsulating with SIDH key
pkSidh := NewPublicKey(params.Id, KeyVariant_SIDH_B)
prSidh := NewPrivateKey(params.Id, KeyVariant_SIDH_B)
_, _, err = Encapsulate(rand.Reader, pkSidh)
if err == nil {
t.Error("encapsulation accepts SIDH public key")
}
// Try decapsulating with SIDH key
_, err = Decapsulate(prSidh, pk, ct)
if err == nil {
t.Error("decapsulation accepts SIDH private key key")
}
}

// In case invalid ciphertext is provided, SIKE's decapsulation must
// return same (but unpredictable) result for a given key.
func testNegativeKEMSameWrongResult(t *testing.T, id uint8) {
sk := NewPrivateKey(id, KeyVariant_SIKE)
checkErr(t, sk.Generate(rand.Reader), "error: key generation")
pk := sk.GeneratePublicKey()

ct, encSs, err := Encapsulate(rand.Reader, pk)
checkErr(t, err, "pre-requisite for a test failed")

// make ciphertext wrong
ct[0] = ct[0] - 1
decSs1, err := Decapsulate(sk, pk, ct)
checkErr(t, err, "pre-requisite for a test failed")

// second decapsulation must be done with same, but imported private key
expSk := sk.Export()

// creat new private key
sk = NewPrivateKey(params.Id, KeyVariant_SIKE)
err = sk.Import(expSk)
checkErr(t, err, "import failed")

// try decapsulating again. ss2 must be same as ss1 and different than
// original plaintext
decSs2, err := Decapsulate(sk, pk, ct)
checkErr(t, err, "pre-requisite for a test failed")

if !bytes.Equal(decSs1, decSs2) {
t.Error("decapsulation is insecure")
}

if bytes.Equal(encSs, decSs1) || bytes.Equal(encSs, decSs2) {
// this test requires that decapsulation returns wrong result
t.Errorf("test implementation error")
}
}

func readAndCheckLine(r *bufio.Reader) []byte {
// Read next line from buffer
line, isPrefix, err := r.ReadLine()
if err != nil || isPrefix {
panic("Wrong format of input file")
}

// Function expects that line is in format "KEY = HEX_VALUE". Get
// value, which should be a hex string
hexst := strings.Split(string(line), "=")[1]
hexst = strings.TrimSpace(hexst)
// Convert value to byte string
ret, err := hex.DecodeString(hexst)
if err != nil {
panic("Wrong format of input file")
}
return ret
}

func testKeygen(pk, sk []byte) bool {
// Import provided private key
var prvKey = NewPrivateKey(params.Id, KeyVariant_SIKE)
if prvKey.Import(sk) != nil {
panic("sike test: can't load KAT")
}

// Generate public key
pubKey := prvKey.GeneratePublicKey()
return bytes.Equal(pubKey.Export(), pk)
}

func testDecapsulation(pk, sk, ct, ssExpected []byte) bool {
var pubKey = NewPublicKey(params.Id, KeyVariant_SIKE)
var prvKey = NewPrivateKey(params.Id, KeyVariant_SIKE)
if pubKey.Import(pk) != nil || prvKey.Import(sk) != nil {
panic("sike test: can't load KAT")
}

ssGot, err := Decapsulate(prvKey, pubKey, ct)
if err != nil {
panic("sike test: can't perform decapsulation KAT")
}

if err != nil {
return false
}
return bytes.Equal(ssGot, ssExpected)
}

func testSIKE_KAT(t *testing.T, id uint8) {
f, err := os.Open(tdata[id].KatFile)
if err != nil {
t.Fatal(err)
}

r := bufio.NewReader(f)
for {
line, isPrefix, err := r.ReadLine()
if err != nil || isPrefix {
if err == io.EOF {
break
} else {
t.Fatal(err)
}
}
if len(strings.TrimSpace(string(line))) == 0 || line[0] == '#' {
continue
}

// count
count := strings.Split(string(line), "=")[1]
// seed
_ = readAndCheckLine(r)
// pk
pk := readAndCheckLine(r)
// sk (secret key in test vector is concatenation of
// MSG + SECRET_BOB_KEY + PUBLIC_BOB_KEY. We use only MSG+SECRET_BOB_KEY
sk := readAndCheckLine(r)
sk = sk[:params.MsgLen+uint(params.B.SecretByteLen)]
// ct
ct := readAndCheckLine(r)
// ss
ss := readAndCheckLine(r)

if !testKeygen(pk, sk) {
t.Fatalf("KAT keygen form private failed at %s\n", count)
}

if !testDecapsulation(pk, sk, ct, ss) {
t.Fatalf("KAT decapsulation failed at %s\n", count)
}

// aditionally test roundtrip with a keypair
testKEMRoundTrip(t, pk, sk, id)
}
}

// Interface to "testing"
func TestPKEKeyGeneration(t *testing.T) { Do(testPKEKeyGeneration, t) }
func TestPKERoundTrip(t *testing.T) { Do(testPKERoundTrip, t) }
func TestNegativePKE(t *testing.T) { Do(testNegativePKE, t) }
func TestKEMKeyGeneration(t *testing.T) { Do(testKEMKeyGeneration, t) }
func TestNegativeKEM(t *testing.T) { Do(testNegativeKEM, t) }
func TestSIKE_KAT(t *testing.T) { Do(testSIKE_KAT, t) }
func TestNegativeKEMSameWrongResult(t *testing.T) { Do(testNegativeKEMSameWrongResult, t) }

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