Add test for encryption and VSS #3
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| func TestEncryptedDeal_Serialization(t *testing.T) { | ||
| nbV3 := 3 | ||
| nbV4 := 7 | ||
| nbVerifiers := nbV3 + nbV4 | ||
| threshold := pedersenv3.MinimumT(nbVerifiers) | ||
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| // Generate all the public/secret keys | ||
| _, publicKeys := genPubSecKeys(nbV3, nbV4) | ||
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| var dealer VersionlessDealer | ||
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| // Create the dealer | ||
| dealer, _, err := genDealerV3(publicKeys, threshold) | ||
| require.NoError(t, err) | ||
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| // 1. dispatch deal | ||
| deals, err := dealer.(*DealerV3).EncryptedDeals() | ||
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| // Encode the deals to bytes | ||
| dealsBytes := make([][]byte, len(deals)) | ||
| for i, deal := range deals { | ||
| dealBytes, err := protobuf.Encode(deal) | ||
| require.NoError(t, err) | ||
| dealsBytes[i] = dealBytes | ||
| } | ||
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| // Decode the deals to V3 | ||
| for i, deal := range dealsBytes { | ||
| dealV3 := &pedersenv3.EncryptedDeal{} | ||
| err := protobuf.Decode(deal, dealV3) | ||
| require.NoError(t, err) | ||
| dealOg := deals[i] | ||
| require.Equal(t, dealOg.DHKey, dealV3.DHKey) | ||
| require.Equal(t, dealOg.Nonce, dealV3.Nonce) | ||
| require.Equal(t, dealOg.Cipher, dealV3.Cipher) | ||
| require.Equal(t, dealOg.Signature, dealV3.Signature) | ||
| } | ||
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| // Decode the deals to V4 | ||
| for i, deal := range dealsBytes { | ||
| dealV4 := &pedersenv4.EncryptedDeal{} | ||
| err := protobuf.Decode(deal, dealV4) | ||
| require.NoError(t, err) | ||
| dealOg := deals[i] | ||
| require.Equal(t, dealOg.DHKey, dealV4.DHKey) | ||
| require.Equal(t, dealOg.Cipher, dealV4.Cipher) | ||
| require.Equal(t, dealOg.Signature, dealV4.Signature) | ||
| } | ||
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| } |
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This test does not pass because EncryptedDeal struct is not compatible between version 3 and 4 of Kyber:
Version 3:
type EncryptedDeal struct {
DHKey []byte
Signature []byte
Nonce []byte
Cipher []byte
}
Version 4:
type EncryptedDeal struct {
DHKey []byte
Signature []byte
Cipher []byte
}
Thus, when decoding from V3 to V4, the Nonce from V3 is interpreted as the cipher in V4. Conversly, the Cipher in V4 is interpreted as the Nonce in V3 when encoding/decoding the other way around
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One simple fix from V3 to V4 is to re-order Nonce and Cipher in the V3 struct
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But, there also is a more subtil difference which is that the PriSharestruct in V3 contains an index field int and in V4 uint32. This is a problem because the way Kyber's protobuf is designed, all int field are encoded using zigzag (i.e. PriShare field is encoded, then it's index, say 3, is encoded as
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We can't really modify V3, not without breaking the API promise. How come the nonce is gone?
Worst case we can have a placeholder array that is explicitly ignored.
Regarding the int / uint32 this is a known issue that we need to address. I have a few ideas, let's talk about it either this Friday or next week.
Add cross-versions test:
encrypt_test.govss_test.go