internal/wycheproof: update TestEcdsa to use ecdsa.VerifyASN1

Change-Id: Ibd6ce156550615cb85c06e734641c34fca0cfcd0
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/220697
Run-TryBot: Katie Hockman <katie@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Filippo Valsorda <filippo@golang.org>

internal/wycheproof/ecdsa_compat_test.go

@@ -1,10 +1,12 @@
-// Copyright 2019 The Go Authors. All rights reserved.
+// Copyright 2020 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Package ecdsa provides an internal version of ecdsa.Verify
-// that is used for the Wycheproof tests.
-package ecdsa
+// +build !go1.15
+
+// ecdsa.VerifyASN1 was added in Go 1.15.
+
+package wycheproof
 
 import (
 	"crypto/ecdsa"
@@ -14,9 +16,7 @@ import (
 	"golang.org/x/crypto/cryptobyte/asn1"
 )
 
-// VerifyASN1 verifies the ASN1 encoded signature, sig, of hash using the
-// public key, pub. Its return value records whether the signature is valid.
-func VerifyASN1(pub *ecdsa.PublicKey, hash, sig []byte) bool {
+func verifyASN1(pub *ecdsa.PublicKey, hash, sig []byte) bool {
 	var (
 		r, s  = &big.Int{}, &big.Int{}
 		inner cryptobyte.String

internal/wycheproof/ecdsa_go115_test.go

@@ -0,0 +1,15 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build go1.15
+
+package wycheproof
+
+import (
+	"crypto/ecdsa"
+)
+
+func verifyASN1(pub *ecdsa.PublicKey, hash, sig []byte) bool {
+	return ecdsa.VerifyASN1(pub, hash, sig)
+}

internal/wycheproof/ecdsa_test.go

@@ -7,8 +7,6 @@ package wycheproof
 import (
 	"crypto/ecdsa"
 	"testing"
-
-	wecdsa "golang.org/x/crypto/internal/wycheproof/internal/ecdsa"
 )
 
 func TestEcdsa(t *testing.T) {
@@ -157,7 +155,7 @@ func TestEcdsa(t *testing.T) {
 			h.Reset()
 			h.Write(decodeHex(sig.Msg))
 			hashed := h.Sum(nil)
-			got := wecdsa.VerifyASN1(pub, hashed, decodeHex(sig.Sig))
+			got := verifyASN1(pub, hashed, decodeHex(sig.Sig))
 			if want := shouldPass(sig.Result, sig.Flags, flagsShouldPass); got != want {
 				t.Errorf("tcid: %d, type: %s, comment: %q, wanted success: %t", sig.TcId, sig.Result, sig.Comment, want)
 			}