feat(testutil): key generation should support both ed25519 and secp256k1.

[Unique-Divine]

Context

All of our key generation util functions in x/common/testutil are generated from ed25519. I found out when trying to import one of these accounts to the validator node's clientCtx.Keyring that support was never added on the binary for ed25519 keys.

• Background
• Reproducibility
• Desired Solution

Background

It seems the feature was de-prioritized and never implemented according to the comments in the SDK repo:

zmanian: "Disagree on Prelaunch. All fundraiser keys are secp keys. No one can even really use a new keypair until transfers are enabled."

ValarDragon: "That sounds good to me! This is definitely something that will be easier to support later. (Doesn't even involve changing the version) I think I'll just close this, and we can look into ed25519 again post launch / after hd derivation is suitably standardized."

• keys: Should support ed25519 cosmos/cosmos-sdk#1861
• Create ed25519 proto compatible with ADR-28 cosmos/cosmos-sdk#9227

Reproducibility

This was some of the code I wrote that made the error apparent:

import (
  // ...
  "github.com/cosmos/cosmos-sdk/crypto"
  cryptotypes "github.com/cosmos/cosmos-sdk/crypto/types"
)

type Account struct {
	privKey    cryptotypes.PrivKey
	addr       sdk.AccAddress
	passphrase string
}

func (s *IntegrationSuite) AddRootToKeyring(root Account) {
	s.T().Log("add the x/sudo root account to the clientCtx.Keyring")
	// Encrypt the x/sudo root account's private key to get its "armor"
	passphrase := root.passphrase
	privKey := root.privKey
	armor := crypto.EncryptArmorPrivKey(privKey, passphrase, privKey.Type())
	// Import this account to the keyring
	val := s.network.Validators[0]
	s.NoError(
		val.ClientCtx.Keyring.ImportPrivKey("root", armor, passphrase),
	)
}

The root account was created using the PrivKeyAddresPairs function. The semantically relevant part of that function is:

func PrivKeyAddressPairs(n int) (keys []cryptotypes.PrivKey, addrs []sdk.AccAddress) {
    // ... {
    keys[i] = ed25519.GenPrivKeyFromSecret(secret)
    addrs[i] = sdk.AccAddress(keys[i].PubKey().Address())
  }
  return
}

I executed a transaction with the root as the sender and got the following output.

{
  "height": "0",
  "txhash": "58DBC804E118DC1D4BED13708BD2F3A15B41A61FF1828A40442DDA0BD1513DCA",
  "codespace": "sdk",
  "code": 8,
  "data": "",
  "raw_log": "ED25519 public keys are unsupported: invalid pubkey",
  "logs": [],
  "info": "",
  "gas_wanted": "200000",
  "gas_used": "53347",
  "tx": null,
  "timestamp": "",
  "events": []
}

Desired Solution

Both the testutil.AccAddress and testutil.PrivKeyAddressPairs functions in x/common/testutil should generate keys with secp256k1 instead of ed25519. We can replace or rename the current versions of these functions.