Move ./lib/runtime/sig_verifier.go to ./lib/crypto package

[EclesioMeloJunior]

Issue summary

• The file ./lib/runtime/sig_verifier.go placed at the runtime package does not depend on runtime stuff, and it just acts like a worker that verifies batch signatures in a concurrently way.
• We need to move the file to ./lib/crypto package as make more sense to that file be there.

Other information and links

• N/A

[kevinliao852]

Can I take this

[EclesioMeloJunior]

Can I take this

Go for it!

[kevinliao852]

@EclesioMeloJunior
Hi, I found that if I move sig_verifier.go to ./lib/crypto directory, it would have an importing cycle issue. I think it is because there are two packages, ed25519 and ed25519, which are the dependencies of sig_verifier.go.
Do you have any suggestions for dealing with it?

[EclesioMeloJunior]

@kevinliao852, sorry for the delay!
ok, yeah, there is one way to avoid the cycle importing.
I would suggest doing:

1. Create a new type called SigVerifyFunc of func(pubkey, sig, msg []byte) (bool, error)

type SigVerifyFunc func(pubkey, sig, msg []byte) (bool, error)

2. Change the Signature field KeyTypeID crypto.KeyType to VerifyFunc SigVerifyFunc
3. For each lib/crypto/ed25519, lib/crypto/sr25519, lib/crypto/secp256k1 package create a function called BatchSignVerify that satisfy the signature of the type SigVerifyFunc we created in step 1. In other words each of these function will do what has been done in the Signature.verify() method

// lib/crypto/secp256k1
func BatchSignVerify(pubkey, sig, msg []byte) (bool, error) {
	result := secp256k1.VerifySignature(pubkey, msg, sig)
	return result, nil
}

// lib/crypto/sr25519
func BatchSignVerify(pubkey, sig, msg []byte) (bool, error) {
	pubKey, err := NewPublicKey(pubkey)
	if err != nil {
		return false, fmt.Errorf("failed to fetch sr25519 public key: %s", err)
	}

	return pubKey.Verify(msg, sig)
}

// lib/crypto/ed25519
...

4. Remove the Signature.verify() method and in the Signature.Start() instead of call sig.verify you will call:

ok, err := sign.VerifyFunc(sign.PubKey, sign.Sign, sign.Msg)
if err != nil || !ok {
	log.Error("[ext_crypto_start_batch_verify_version_1]", "error", err)
	sv.Invalid()
	return
}

5. Just adjust the lib/runtime/wasmer/imports.go to

// instead of use the `crypto.Secp256k1Type`
signature := runtime.Signature{
	PubKey:    pub.Encode(),
	Sign:      signature,
	Msg:       hash[:],
	KeyTypeID: crypto.Secp256k1Type,
}

// use the `secp256k1.BatchSignVerify`
signature := crytpo.Signature{
	PubKey:    pub.Encode(),
	Sign:      signature,
	Msg:       hash[:],
	VerifyFunc: secp256k1.BatchSignVerify,
}

this way you can move the batch signature verification to lib/crypto package without the cycle issue.
If you need more help don't hesitate to reach me out on gossamer discord