// Copyright 2020 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
////////////////////////////////////////////////////////////////////////////////

package subtle_test

import (
	"bytes"
	"crypto/ecdsa"
	"crypto/elliptic"
	"crypto/x509"
	"encoding/hex"
	"errors"
	"fmt"
	"math/big"
	"strings"
	"testing"

	"github.com/google/tink/go/hybrid/subtle"
	"github.com/google/tink/go/testutil"
)

// The tests are from
// http://google.github.io/end-to-end/api/source/src/javascript/crypto/e2e/ecc/ecdh_testdata.js.src.html.
type testEC1 struct {
	elliptic.Curve
	pubX, pubY string
}

type testEC2 struct {
	elliptic.Curve
	pointFormat string
	encoded     string
	X, Y        string
}

var (
	tEC1 = []testEC1{
		{
			elliptic.P256(),
			"700c48f77f56584c5cc632ca65640db91b6bacce3a4df6b42ce7cc838833d287",
			"db71e509e3fd9b060ddb20ba5c51dcc5948d46fbf640dfe0441782cab85fa4ac",
		},
		{
			elliptic.P256(),
			"809f04289c64348c01515eb03d5ce7ac1a8cb9498f5caa50197e58d43a86a7ae",
			"b29d84e811197f25eba8f5194092cb6ff440e26d4421011372461f579271cda3",
		},
		{
			elliptic.P256(),
			"df3989b9fa55495719b3cf46dccd28b5153f7808191dd518eff0c3cff2b705ed",
			"422294ff46003429d739a33206c8752552c8ba54a270defc06e221e0feaf6ac4",
		},
		{
			elliptic.P256(),
			"356c5a444c049a52fee0adeb7e5d82ae5aa83030bfff31bbf8ce2096cf161c4b",
			"57d128de8b2a57a094d1a001e572173f96e8866ae352bf29cddaf92fc85b2f92",
		},
		{
			elliptic.P384(),
			"a7c76b970c3b5fe8b05d2838ae04ab47697b9eaf52e764592efda27fe7513272" +
				"734466b400091adbf2d68c58e0c50066",
			"ac68f19f2e1cb879aed43a9969b91a0839c4c38a49749b661efedf243451915e" +
				"d0905a32b060992b468c64766fc8437a",
		},
		{
			elliptic.P384(),
			"30f43fcf2b6b00de53f624f1543090681839717d53c7c955d1d69efaf0349b736" +
				"3acb447240101cbb3af6641ce4b88e0",
			"25e46c0c54f0162a77efcc27b6ea792002ae2ba82714299c860857a68153ab62e" +
				"525ec0530d81b5aa15897981e858757",
		},
		{
			elliptic.P521(),
			"000000685a48e86c79f0f0875f7bc18d25eb5fc8c0b07e5da4f4370f3a9490340" +
				"854334b1e1b87fa395464c60626124a4e70d0f785601d37c09870ebf176666877a2" +
				"046d",
			"000001ba52c56fc8776d9e8f5db4f0cc27636d0b741bbe05400697942e80b7398" +
				"84a83bde99e0f6716939e632bc8986fa18dccd443a348b6c3e522497955a4f3c302" +
				"f676",
		},
		{
			elliptic.P521(),
			"000001df277c152108349bc34d539ee0cf06b24f5d3500677b4445453ccc21409" +
				"453aafb8a72a0be9ebe54d12270aa51b3ab7f316aa5e74a951c5e53f74cd95fc29a" +
				"ee7a",
			"0000013d52f33a9f3c14384d1587fa8abe7aed74bc33749ad9c570b471776422c" +
				"7d4505d9b0a96b3bfac041e4c6a6990ae7f700e5b4a6640229112deafa0cd8bb0d0" +
				"89b0",
		},
		{
			elliptic.P521(),
			"00000092db3142564d27a5f0006f819908fba1b85038a5bc2509906a497daac67" +
				"fd7aee0fc2daba4e4334eeaef0e0019204b471cd88024f82115d8149cc0cf4f7ce1" +
				"a4d5",
			"0000016bad0623f517b158d9881841d2571efbad63f85cbe2e581960c5d670601" +
				"a6760272675a548996217e4ab2b8ebce31d71fca63fcc3c08e91c1d8edd91cf6fe8" +
				"45f8",
		},
		{
			elliptic.P521(),
			"0000004f38816681771289ce0cb83a5e29a1ab06fc91f786994b23708ff08a08a" +
				"0f675b809ae99e9f9967eb1a49f196057d69e50d6dedb4dd2d9a81c02bdcc8f7f51" +
				"8460",
			"0000009efb244c8b91087de1eed766500f0e81530752d469256ef79f6b965d8a2" +
				"232a0c2dbc4e8e1d09214bab38485be6e357c4200d073b52f04e4a16fc6f5247187" +
				"aecb",
		},
		{
			elliptic.P521(),
			"000001a32099b02c0bd85371f60b0dd20890e6c7af048c8179890fda308b359db" +
				"bc2b7a832bb8c6526c4af99a7ea3f0b3cb96ae1eb7684132795c478ad6f962e4a6f" +
				"446d",
			"0000017627357b39e9d7632a1370b3e93c1afb5c851b910eb4ead0c9d387df67c" +
				"de85003e0e427552f1cd09059aad0262e235cce5fba8cedc4fdc1463da76dcd4b6d" +
				"1a46",
		},
	}
	tEC2 = []testEC2{
		// NIST_P256
		{
			elliptic.P256(),
			"UNCOMPRESSED",
			"04" +
				"b0cfc7bc02fc980d858077552947ffb449b10df8949dee4e56fe21e016dcb25a" +
				"1886ccdca5487a6772f9401888203f90587cc00a730e2b83d5c6f89b3b568df7",
			"79974177209371530366349631093481213364328002500948308276357601809416549347930",
			"11093679777528052772423074391650378811758820120351664471899251711300542565879",
		},
		{
			elliptic.P256(),
			"DO_NOT_USE_CRUNCHY_UNCOMPRESSED",
			"b0cfc7bc02fc980d858077552947ffb449b10df8949dee4e56fe21e016dcb25a" +
				"1886ccdca5487a6772f9401888203f90587cc00a730e2b83d5c6f89b3b568df7",
			"79974177209371530366349631093481213364328002500948308276357601809416549347930",
			"11093679777528052772423074391650378811758820120351664471899251711300542565879",
		},
		{
			elliptic.P256(),
			"COMPRESSED",
			"03b0cfc7bc02fc980d858077552947ffb449b10df8949dee4e56fe21e016dcb25a",
			"79974177209371530366349631093481213364328002500948308276357601809416549347930",
			"11093679777528052772423074391650378811758820120351664471899251711300542565879",
		},
		// Exceptional point: x==0
		{
			elliptic.P256(),
			"UNCOMPRESSED",
			"04" +
				"0000000000000000000000000000000000000000000000000000000000000000" +
				"66485c780e2f83d72433bd5d84a06bb6541c2af31dae871728bf856a174f93f4",
			"0",
			"46263761741508638697010950048709651021688891777877937875096931459006746039284",
		},
		{
			elliptic.P256(),
			"DO_NOT_USE_CRUNCHY_UNCOMPRESSED",
			"0000000000000000000000000000000000000000000000000000000000000000" +
				"66485c780e2f83d72433bd5d84a06bb6541c2af31dae871728bf856a174f93f4",
			"0",
			"46263761741508638697010950048709651021688891777877937875096931459006746039284",
		},
		{
			elliptic.P256(),
			"COMPRESSED",
			"020000000000000000000000000000000000000000000000000000000000000000",
			"0",
			"46263761741508638697010950048709651021688891777877937875096931459006746039284",
		},
		// Exceptional point: x==-3
		{
			elliptic.P256(),
			"UNCOMPRESSED",
			"04" +
				"ffffffff00000001000000000000000000000000fffffffffffffffffffffffc" +
				"19719bebf6aea13f25c96dfd7c71f5225d4c8fc09eb5a0ab9f39e9178e55c121",
			"115792089210356248762697446949407573530086143415290314195533631308867097853948",
			"11508551065151498768481026661199445482476508121209842448718573150489103679777",
		},
		{
			elliptic.P256(),
			"DO_NOT_USE_CRUNCHY_UNCOMPRESSED",
			"ffffffff00000001000000000000000000000000fffffffffffffffffffffffc" +
				"19719bebf6aea13f25c96dfd7c71f5225d4c8fc09eb5a0ab9f39e9178e55c121",
			"115792089210356248762697446949407573530086143415290314195533631308867097853948",
			"11508551065151498768481026661199445482476508121209842448718573150489103679777",
		},
		{
			elliptic.P256(),
			"COMPRESSED",
			"03ffffffff00000001000000000000000000000000fffffffffffffffffffffffc",
			"115792089210356248762697446949407573530086143415290314195533631308867097853948",
			"11508551065151498768481026661199445482476508121209842448718573150489103679777",
		},
		// NIST_P384
		{
			elliptic.P384(),
			"UNCOMPRESSED",
			"04aa87ca22be8b05378eb1c71ef320ad746e1d3b628ba79b9859f741e082542a" +
				"385502f25dbf55296c3a545e3872760ab73617de4a96262c6f5d9e98bf9292dc" +
				"29f8f41dbd289a147ce9da3113b5f0b8c00a60b1ce1d7e819d7a431d7c90ea0e" +
				"5f",
			"2624703509579968926862315674456698189185292349110921338781561590" +
				"0925518854738050089022388053975719786650872476732087",
			"8325710961489029985546751289520108179287853048861315594709205902" +
				"480503199884419224438643760392947333078086511627871",
		},
		{
			elliptic.P384(),
			"COMPRESSED",
			"03aa87ca22be8b05378eb1c71ef320ad746e1d3b628ba79b9859f741e082542a" +
				"385502f25dbf55296c3a545e3872760ab7",
			"2624703509579968926862315674456698189185292349110921338781561590" +
				"0925518854738050089022388053975719786650872476732087",
			"8325710961489029985546751289520108179287853048861315594709205902" +
				"480503199884419224438643760392947333078086511627871",
		},
		// x = 0
		{
			elliptic.P384(),
			"UNCOMPRESSED",
			"0400000000000000000000000000000000000000000000000000000000000000" +
				"00000000000000000000000000000000003cf99ef04f51a5ea630ba3f9f960dd" +
				"593a14c9be39fd2bd215d3b4b08aaaf86bbf927f2c46e52ab06fb742b8850e52" +
				"1e",
			"0",
			"9384923975005507693384933751151973636103286582194273515051780595" +
				"652610803541482195894618304099771370981414591681054",
		},
		{
			elliptic.P384(),
			"COMPRESSED",
			"0200000000000000000000000000000000000000000000000000000000000000" +
				"0000000000000000000000000000000000",
			"0",
			"9384923975005507693384933751151973636103286582194273515051780595" +
				"652610803541482195894618304099771370981414591681054",
		},
		// x = 2
		{
			elliptic.P384(),
			"UNCOMPRESSED",
			"0400000000000000000000000000000000000000000000000000000000000000" +
				"0000000000000000000000000000000002732152442fb6ee5c3e6ce1d920c059" +
				"bc623563814d79042b903ce60f1d4487fccd450a86da03f3e6ed525d02017bfd" +
				"b3",
			"2",
			"1772015366480916228638409476801818679957736647795608728422858375" +
				"4887974043472116432532980617621641492831213601947059",
		},
		{
			elliptic.P384(),
			"COMPRESSED",
			"0300000000000000000000000000000000000000000000000000000000000000" +
				"0000000000000000000000000000000002",
			"2",
			"1772015366480916228638409476801818679957736647795608728422858375" +
				"4887974043472116432532980617621641492831213601947059",
		},
		// x = -3
		{
			elliptic.P384(),
			"UNCOMPRESSED",
			"04ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff" +
				"feffffffff0000000000000000fffffffc2de9de09a95b74e6b2c430363e1afb" +
				"8dff7164987a8cfe0a0d5139250ac02f797f81092a9bdc0e09b574a8f43bf80c" +
				"17",
			"3940200619639447921227904010014361380507973927046544666794829340" +
				"4245721771496870329047266088258938001861606973112316",
			"7066741234775658874139271223692271325950306561732202191471600407" +
				"582071247913794644254895122656050391930754095909911",
		},
		{
			elliptic.P384(),
			"COMPRESSED",
			"03ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff" +
				"feffffffff0000000000000000fffffffc",
			"3940200619639447921227904010014361380507973927046544666794829340" +
				"4245721771496870329047266088258938001861606973112316",
			"7066741234775658874139271223692271325950306561732202191471600407" +
				"582071247913794644254895122656050391930754095909911",
		},
		// NIST_P521
		{
			elliptic.P521(),
			"UNCOMPRESSED",
			"0400c6858e06b70404e9cd9e3ecb662395b4429c648139053fb521f828af606b" +
				"4d3dbaa14b5e77efe75928fe1dc127a2ffa8de3348b3c1856a429bf97e7e31c2" +
				"e5bd66011839296a789a3bc0045c8a5fb42c7d1bd998f54449579b446817afbd" +
				"17273e662c97ee72995ef42640c550b9013fad0761353c7086a272c24088be94" +
				"769fd16650",
			"2661740802050217063228768716723360960729859168756973147706671368" +
				"4188029449964278084915450806277719023520942412250655586621571135" +
				"45570916814161637315895999846",
			"3757180025770020463545507224491183603594455134769762486694567779" +
				"6155444774405563166912344050129455395621444445372894285225856667" +
				"29196580810124344277578376784",
		},
		{
			elliptic.P521(),
			"COMPRESSED",
			"0200c6858e06b70404e9cd9e3ecb662395b4429c648139053fb521f828af606b" +
				"4d3dbaa14b5e77efe75928fe1dc127a2ffa8de3348b3c1856a429bf97e7e31c2" +
				"e5bd66",
			"2661740802050217063228768716723360960729859168756973147706671368" +
				"4188029449964278084915450806277719023520942412250655586621571135" +
				"45570916814161637315895999846",
			"3757180025770020463545507224491183603594455134769762486694567779" +
				"6155444774405563166912344050129455395621444445372894285225856667" +
				"29196580810124344277578376784",
		},
		// x = 0
		{
			elliptic.P521(),
			"UNCOMPRESSED",
			"0400000000000000000000000000000000000000000000000000000000000000" +
				"0000000000000000000000000000000000000000000000000000000000000000" +
				"00000000d20ec9fea6b577c10d26ca1bb446f40b299e648b1ad508aad068896f" +
				"ee3f8e614bc63054d5772bf01a65d412e0bcaa8e965d2f5d332d7f39f846d440" +
				"ae001f4f87",
			"0",
			"2816414230262626695230339754503506208598534788872316917808418392" +
				"0894686826982898181454171638541149642517061885689521392260532032" +
				"30035588176689756661142736775",
		},
		{
			elliptic.P521(),
			"COMPRESSED",
			"0300000000000000000000000000000000000000000000000000000000000000" +
				"0000000000000000000000000000000000000000000000000000000000000000" +
				"000000",
			"0",
			"2816414230262626695230339754503506208598534788872316917808418392" +
				"0894686826982898181454171638541149642517061885689521392260532032" +
				"30035588176689756661142736775",
		},
		// x = 1
		{
			elliptic.P521(),
			"UNCOMPRESSED",
			"0400000000000000000000000000000000000000000000000000000000000000" +
				"0000000000000000000000000000000000000000000000000000000000000000" +
				"0000010010e59be93c4f269c0269c79e2afd65d6aeaa9b701eacc194fb3ee03d" +
				"f47849bf550ec636ebee0ddd4a16f1cd9406605af38f584567770e3f272d688c" +
				"832e843564",
			"1",
			"2265505274322546447629271557184988697103589068170534253193208655" +
				"0778100463909972583865730916407864371153050622267306901033104806" +
				"9570407113457901669103973732",
		},
		{
			elliptic.P521(),
			"COMPRESSED",
			"0200000000000000000000000000000000000000000000000000000000000000" +
				"0000000000000000000000000000000000000000000000000000000000000000" +
				"000001",
			"1",
			"2265505274322546447629271557184988697103589068170534253193208655" +
				"0778100463909972583865730916407864371153050622267306901033104806" +
				"9570407113457901669103973732",
		},
		// x = 2
		{
			elliptic.P521(),
			"UNCOMPRESSED",
			"0400000000000000000000000000000000000000000000000000000000000000" +
				"0000000000000000000000000000000000000000000000000000000000000000" +
				"00000200d9254fdf800496acb33790b103c5ee9fac12832fe546c632225b0f7f" +
				"ce3da4574b1a879b623d722fa8fc34d5fc2a8731aad691a9a8bb8b554c95a051" +
				"d6aa505acf",
			"2",
			"2911448509017565583245824537994174021964465504209366849707937264" +
				"0417919148200722009442607963590225526059407040161685364728526719" +
				"10134103604091376779754756815",
		},
		{
			elliptic.P521(),
			"COMPRESSED",
			"0300000000000000000000000000000000000000000000000000000000000000" +
				"0000000000000000000000000000000000000000000000000000000000000000" +
				"000002",
			"2",
			"2911448509017565583245824537994174021964465504209366849707937264" +
				"0417919148200722009442607963590225526059407040161685364728526719" +
				"10134103604091376779754756815",
		},
		// x = -2
		{
			elliptic.P521(),
			"UNCOMPRESSED",
			"0401ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff" +
				"ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff" +
				"fffffd0010e59be93c4f269c0269c79e2afd65d6aeaa9b701eacc194fb3ee03d" +
				"f47849bf550ec636ebee0ddd4a16f1cd9406605af38f584567770e3f272d688c" +
				"832e843564",
			"6864797660130609714981900799081393217269435300143305409394463459" +
				"1855431833976560521225596406614545549772963113914808580371219879" +
				"99716643812574028291115057149",
			"2265505274322546447629271557184988697103589068170534253193208655" +
				"0778100463909972583865730916407864371153050622267306901033104806" +
				"9570407113457901669103973732",
		},
		{
			elliptic.P521(),
			"COMPRESSED",
			"0201ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff" +
				"ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff" +
				"fffffd",
			"6864797660130609714981900799081393217269435300143305409394463459" +
				"1855431833976560521225596406614545549772963113914808580371219879" +
				"99716643812574028291115057149",
			"2265505274322546447629271557184988697103589068170534253193208655" +
				"0778100463909972583865730916407864371153050622267306901033104806" +
				"9570407113457901669103973732",
		},
	}
)

func TestPointOnCurve(t *testing.T) {
	for i := 0; i < len(tEC1); i++ {
		x, y, ye := new(big.Int), new(big.Int), new(big.Int)
		x.SetString(tEC1[i].pubX, 16)
		y.SetString(tEC1[i].pubY, 16)
		ye.Sub(y, big.NewInt(1))
		if !tEC1[i].Curve.IsOnCurve(x, y) {
			t.Fatalf("valid points not on curve for test case :%d", i)
		}
		if tEC1[i].Curve.IsOnCurve(x, ye) {
			t.Fatalf("invalid points is on curve for test case :%d", i)
		}
	}

}

func TestPointEncode(t *testing.T) {
	for i := 0; i < len(tEC2); i++ {
		x, y := new(big.Int), new(big.Int)
		x.SetString(tEC2[i].X, 10)
		y.SetString(tEC2[i].Y, 10)
		p := subtle.ECPoint{
			X: x,
			Y: y,
		}
		encodedpoint, err := subtle.PointEncode(tEC2[i].Curve, tEC2[i].pointFormat, p)
		if err != nil {
			t.Errorf("error in point encoding in test case %d : %v", i, err)
		}
		want, err := hex.DecodeString(tEC2[i].encoded)
		if err != nil {
			t.Errorf("error reading encoded point in test case %d", i)
		}
		if !bytes.Equal(encodedpoint, want) {
			t.Errorf("mismatch point encoding in test case %d", i)
		}
	}
}

func TestPointDecode(t *testing.T) {
	for i := 0; i < len(tEC2); i++ {
		x, y := new(big.Int), new(big.Int)
		x.SetString(tEC2[i].X, 10)
		y.SetString(tEC2[i].Y, 10)
		e, err := hex.DecodeString(tEC2[i].encoded)
		if err != nil {
			t.Errorf("error reading encoded point in test case %d", i)
		}
		pt, err := subtle.PointDecode(tEC2[i].Curve, tEC2[i].pointFormat, e)
		if err != nil {
			t.Errorf("error in point decoding in test case %d: %v", i, err)
		}
		spt := subtle.ECPoint{
			X: x,
			Y: y,
		}

		if pt.X.Cmp(spt.X) != 0 || pt.Y.Cmp(spt.Y) != 0 {
			t.Errorf("mismatch point decoding in test case %d", i)
		}
	}
}

func checkFlag(t *testing.T, flags []string, check []string) bool {
	t.Helper()
	for _, f := range flags {
		for _, c := range check {
			if strings.Compare(f, c) == 0 {
				return true
			}
		}
	}
	return false
}

// convertX509PublicKey converts an encoded public key to an ECPublicKey.
func convertX509PublicKey(t *testing.T, b []byte) (*subtle.ECPublicKey, error) {
	t.Helper()
	pkey, err := x509.ParsePKIXPublicKey(b)
	if err != nil {
		return nil, err
	}
	ecdsaP, ok := pkey.(*ecdsa.PublicKey)
	if !ok {
		return nil, errors.New("invalid elliptic curve key")
	}
	return &subtle.ECPublicKey{
		Curve: ecdsaP.Curve,
		Point: subtle.ECPoint{
			X: ecdsaP.X,
			Y: ecdsaP.Y,
		},
	}, nil
}

// convertPointPublicKey converts an EC point public key to an ECPublicKey.
func convertPointPublicKey(t *testing.T, pk []byte, curve elliptic.Curve, flags []string) (*subtle.ECPublicKey, error) {
	ptFormat := "UNCOMPRESSED"
	if checkFlag(t, flags, []string{"CompressedPoint"}) {
		ptFormat = "COMPRESSED"
	}
	pt, err := subtle.PointDecode(curve, ptFormat, pk)
	if err != nil {
		return nil, err
	}
	return &subtle.ECPublicKey{
		Curve: curve,
		Point: *pt,
	}, nil
}

func TestECWycheproofCases(t *testing.T) {
	testutil.SkipTestIfTestSrcDirIsNotSet(t)

	vectors := []string{
		"ecdh_test.json",
		"ecdh_secp224r1_ecpoint_test.json",
		"ecdh_secp256r1_ecpoint_test.json",
		"ecdh_secp384r1_ecpoint_test.json",
		"ecdh_secp521r1_ecpoint_test.json",
	}
	for _, v := range vectors {
		suite := new(ecdhSuite)
		if err := testutil.PopulateSuite(suite, v); err != nil {
			t.Fatalf("failed populating suite: %s", err)
		}
		for _, group := range suite.TestGroups {
			curve, err := subtle.GetCurve(group.Curve)
			if err != nil {
				t.Logf("unsupported curve: %s", group.Curve)
				continue
			}
			for _, test := range group.Tests {
				caseName := fmt.Sprintf("%s-%s:Case-%d", suite.Algorithm, group.Type, test.CaseID)
				t.Run(caseName, func(t *testing.T) {
					pvtKey := subtle.GetECPrivateKey(curve, test.Private)

					var pubKey *subtle.ECPublicKey
					var errPub error
					switch suite.Schema {
					case "ecdh_test_schema.json":
						pubKey, errPub = convertX509PublicKey(t, test.Public)
					case "ecdh_ecpoint_test_schema.json":
						pubKey, errPub = convertPointPublicKey(t, test.Public, curve, test.Flags)
					default:
						t.Logf("Unsupported schema: %q", suite.Schema)
						return
					}

					switch test.Result {
					case "valid":
						if errPub != nil {
							t.Fatalf("failed decoding public key: %s", errPub)
						}

						shared, err := subtle.ComputeSharedSecret(&pubKey.Point, pvtKey)
						if err != nil {
							t.Errorf("subtle.ComputeSharedSecret() failed: %s", err)
						}
						if !bytes.Equal(shared, test.Shared) {
							t.Error("valid test case, incorrect shared secret")
						}

					case "invalid":
						if errPub != nil {
							// Public key not decoded. OK for invalid test case.
							return
						}

						shared, err := subtle.ComputeSharedSecret(&pubKey.Point, pvtKey)
						if err != nil {
							// Shared secret was not computed. OK for invalid test case.
							return
						}
						validReason := checkFlag(t, test.Flags, []string{"WrongOrder", "WeakPublicKey", "UnnamedCurve"})
						if validReason && bytes.Equal(shared, test.Shared) {
							t.Log("accepted invalid parameters but shared secret is correct")
							return
						}
						t.Error("accepted invalid parameters")

					case "acceptable":
						if errPub != nil {
							// Public key not decoded. OK for acceptable test case.
							return
						}

						shared, err := subtle.ComputeSharedSecret(&pubKey.Point, pvtKey)
						if err != nil {
							// Shared secret was not computed. OK for acceptable test case.
							return
						}
						if !bytes.Equal(shared, test.Shared) {
							t.Error("acceptable test case, incorrect shared secret")
						}

					default:
						t.Errorf("unsupported test result: %q", test.Result)
					}
				})
			}
		}
	}
}