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package group
import (
"bytes"
"crypto/rand"
"encoding/hex"
"testing"
)
// https://tools.ietf.org/html/draft-irtf-cfrg-ristretto255-decaf448-00#appendix-A.1
func TestGeneratorMultiples(t *testing.T) {
encVec := []string{
"0000000000000000000000000000000000000000000000000000000000000000",
"e2f2ae0a6abc4e71a884a961c500515f58e30b6aa582dd8db6a65945e08d2d76",
"6a493210f7499cd17fecb510ae0cea23a110e8d5b901f8acadd3095c73a3b919",
"94741f5d5d52755ece4f23f044ee27d5d1ea1e2bd196b462166b16152a9d0259",
"da80862773358b466ffadfe0b3293ab3d9fd53c5ea6c955358f568322daf6a57",
"e882b131016b52c1d3337080187cf768423efccbb517bb495ab812c4160ff44e",
"f64746d3c92b13050ed8d80236a7f0007c3b3f962f5ba793d19a601ebb1df403",
"44f53520926ec81fbd5a387845beb7df85a96a24ece18738bdcfa6a7822a176d",
"903293d8f2287ebe10e2374dc1a53e0bc887e592699f02d077d5263cdd55601c",
"02622ace8f7303a31cafc63f8fc48fdc16e1c8c8d234b2f0d6685282a9076031",
"20706fd788b2720a1ed2a5dad4952b01f413bcf0e7564de8cdc816689e2db95f",
"bce83f8ba5dd2fa572864c24ba1810f9522bc6004afe95877ac73241cafdab42",
"e4549ee16b9aa03099ca208c67adafcafa4c3f3e4e5303de6026e3ca8ff84460",
"aa52e000df2e16f55fb1032fc33bc42742dad6bd5a8fc0be0167436c5948501f",
"46376b80f409b29dc2b5f6f0c52591990896e5716f41477cd30085ab7f10301e",
"e0c418f7c8d9c4cdd7395b93ea124f3ad99021bb681dfc3302a9d99a2e53e64e",
}
g := Ristretto255
base := g.NewElement()
encBase, err := hex.DecodeString(encVec[0])
if err != nil {
t.Fatal("DecodeString")
}
err = base.UnmarshalBinary(encBase)
if err != nil {
t.Fatal("UnmarshalBinary")
}
if !base.IsIdentity() {
t.Fatal("Base element is not identity")
}
for i := 1; i < len(encVec); i++ {
base.Add(base, g.Generator())
baseEnc, err := base.MarshalBinary()
if err != nil {
t.Fatalf("MarshalBinary %d", i)
}
if hex.EncodeToString(baseEnc) != encVec[i] {
t.Fatalf("Multiple %d mismatch", i)
}
}
}
// https://tools.ietf.org/html/draft-irtf-cfrg-ristretto255-decaf448-00#appendix-A.2
func TestInvalidEncodings(t *testing.T) {
encVec := []string{
// Non-canonical field encodings.
"00ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
"ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff7f",
// The internal ristretto255 implementation ignores the MSB, so the following two encodings fail.
// "f3ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff7f",
// "edffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff7f",
// Negative field elements.
"0100000000000000000000000000000000000000000000000000000000000000",
"01ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff7f",
"ed57ffd8c914fb201471d1c3d245ce3c746fcbe63a3679d51b6a516ebebe0e20",
"c34c4e1826e5d403b78e246e88aa051c36ccf0aafebffe137d148a2bf9104562",
"c940e5a4404157cfb1628b108db051a8d439e1a421394ec4ebccb9ec92a8ac78",
"47cfc5497c53dc8e61c91d17fd626ffb1c49e2bca94eed052281b510b1117a24",
"f1c6165d33367351b0da8f6e4511010c68174a03b6581212c71c0e1d026c3c72",
"87260f7a2f12495118360f02c26a470f450dadf34a413d21042b43b9d93e1309",
// Non-square x^2.
"26948d35ca62e643e26a83177332e6b6afeb9d08e4268b650f1f5bbd8d81d371",
"4eac077a713c57b4f4397629a4145982c661f48044dd3f96427d40b147d9742f",
"de6a7b00deadc788eb6b6c8d20c0ae96c2f2019078fa604fee5b87d6e989ad7b",
"bcab477be20861e01e4a0e295284146a510150d9817763caf1a6f4b422d67042",
"2a292df7e32cababbd9de088d1d1abec9fc0440f637ed2fba145094dc14bea08",
"f4a9e534fc0d216c44b218fa0c42d99635a0127ee2e53c712f70609649fdff22",
"8268436f8c4126196cf64b3c7ddbda90746a378625f9813dd9b8457077256731",
"2810e5cbc2cc4d4eece54f61c6f69758e289aa7ab440b3cbeaa21995c2f4232b",
// Negative xy value.
"3eb858e78f5a7254d8c9731174a94f76755fd3941c0ac93735c07ba14579630e",
"a45fdc55c76448c049a1ab33f17023edfb2be3581e9c7aade8a6125215e04220",
"d483fe813c6ba647ebbfd3ec41adca1c6130c2beeee9d9bf065c8d151c5f396e",
"8a2e1d30050198c65a54483123960ccc38aef6848e1ec8f5f780e8523769ba32",
"32888462f8b486c68ad7dd9610be5192bbeaf3b443951ac1a8118419d9fa097b",
"227142501b9d4355ccba290404bde41575b037693cef1f438c47f8fbf35d1165",
"5c37cc491da847cfeb9281d407efc41e15144c876e0170b499a96a22ed31e01e",
"445425117cb8c90edcbc7c1cc0e74f747f2c1efa5630a967c64f287792a48a4b",
// s = -1, which causes y = 0.
"ecffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff7f",
}
for i, enc := range encVec {
raw, err := hex.DecodeString(enc)
if err != nil {
t.Fatal("DecodeString")
}
err = Ristretto255.NewElement().UnmarshalBinary(raw)
if err == nil {
t.Fatalf("Decode succeeded for vector %d: %v", i, enc)
}
}
}
func TestRistrettoElGamal(t *testing.T) {
g := Ristretto255
pk := g.NewElement()
sk := g.RandomScalar(rand.Reader)
pk.MulGen(sk)
// El'Gamal encrypt a random element p into a ciphertext-pair (c1,c2)
p := g.RandomElement(rand.Reader)
r := g.RandomScalar(rand.Reader)
c2 := g.NewElement()
c1 := g.NewElement()
c2.MulGen(r)
c1.Mul(pk, r)
c1.Add(c1, p)
// Decrypt (c1,c2) back to p
b := g.NewElement()
p2 := g.NewElement()
b.Mul(c2, sk)
p2.Add(c1, b.Neg(b))
if !p.IsEqual(p2) {
t.Fatal("Encryption/decryption failed")
}
pEnc, err := p.MarshalBinary()
if err != nil {
t.Fatal("MarshalBinary")
}
p2Enc, err := p2.MarshalBinary()
if err != nil {
t.Fatal("MarshalBinary")
}
if !bytes.Equal(pEnc, p2Enc) {
t.Fatal("Unequal encodings")
}
}
|
