move EthAddressFromPubKey to chain/types/ethtypes.

lib/sigs/delegated/eth.go

@@ -1,26 +0,0 @@
-package delegated
-
-import (
-	"fmt"
-
-	"golang.org/x/crypto/sha3"
-)
-
-// EthAddressFromPubKey returns the Ethereum address corresponding to an
-// uncompressed secp256k1 public key.
-//
-// TODO move somewhere else, this likely doesn't belong here.
-func EthAddressFromPubKey(pubk []byte) ([]byte, error) {
-	// if we get an uncompressed public key (that's what we get from the library,
-	// but putting this check here for defensiveness), strip the prefix
-	if pubk[0] != 0x04 {
-		return nil, fmt.Errorf("expected first byte of secp256k1 to be 0x04 (uncompressed)")
-	}
-	pubk = pubk[1:]
-
-	// Calculate the Ethereum address based on the keccak hash of the pubkey.
-	hasher := sha3.NewLegacyKeccak256()
-	hasher.Write(pubk)
-	ethAddr := hasher.Sum(nil)[12:]
-	return ethAddr, nil
-}