462ddce5b2
This removes a bunch of weird code around the counter overflow check in concatKDF and makes it actually work for different hash output sizes. The overflow check worked as follows: concatKDF applies the hash function N times, where N is roundup(kdLen, hashsize) / hashsize. N should not overflow 32 bits because that would lead to a repetition in the KDF output. A couple issues with the overflow check: - It used the hash.BlockSize, which is wrong because the block size is about the input of the hash function. Luckily, all standard hash functions have a block size that's greater than the output size, so concatKDF didn't crash, it just generated too much key material. - The check used big.Int to compare against 2^32-1. - The calculation could still overflow before reaching the check. The new code in concatKDF doesn't check for overflow. Instead, there is a new check on ECIESParams which ensures that params.KeyLen is < 512. This removes any possibility of overflow. There are a couple of miscellaneous improvements bundled in with this change: - The key buffer is pre-allocated instead of appending the hash output to an initially empty slice. - The code that uses concatKDF to derive keys is now shared between Encrypt and Decrypt. - There was a redundant invocation of IsOnCurve in Decrypt. This is now removed because elliptic.Unmarshal already checks whether the input is a valid curve point since Go 1.5. Co-authored-by: Felix Lange <fjl@twurst.com>
431 lines
12 KiB
Go
431 lines
12 KiB
Go
// Copyright (c) 2013 Kyle Isom <kyle@tyrfingr.is>
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// Copyright (c) 2012 The Go Authors. All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived from
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// this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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package ecies
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import (
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"bytes"
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"crypto/elliptic"
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"crypto/rand"
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"crypto/sha256"
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"encoding/hex"
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"fmt"
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"math/big"
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"testing"
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"github.com/ethereum/go-ethereum/crypto"
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)
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func TestKDF(t *testing.T) {
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tests := []struct {
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length int
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output []byte
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}{
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{6, decode("858b192fa2ed")},
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{32, decode("858b192fa2ed4395e2bf88dd8d5770d67dc284ee539f12da8bceaa45d06ebae0")},
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{48, decode("858b192fa2ed4395e2bf88dd8d5770d67dc284ee539f12da8bceaa45d06ebae0700f1ab918a5f0413b8140f9940d6955")},
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{64, decode("858b192fa2ed4395e2bf88dd8d5770d67dc284ee539f12da8bceaa45d06ebae0700f1ab918a5f0413b8140f9940d6955f3467fd6672cce1024c5b1effccc0f61")},
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}
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for _, test := range tests {
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h := sha256.New()
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k := concatKDF(h, []byte("input"), nil, test.length)
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if !bytes.Equal(k, test.output) {
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t.Fatalf("KDF: generated key %x does not match expected output %x", k, test.output)
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}
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}
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}
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var ErrBadSharedKeys = fmt.Errorf("ecies: shared keys don't match")
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// cmpParams compares a set of ECIES parameters. We assume, as per the
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// docs, that AES is the only supported symmetric encryption algorithm.
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func cmpParams(p1, p2 *ECIESParams) bool {
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return p1.hashAlgo == p2.hashAlgo &&
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p1.KeyLen == p2.KeyLen &&
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p1.BlockSize == p2.BlockSize
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}
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// Validate the ECDH component.
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func TestSharedKey(t *testing.T) {
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prv1, err := GenerateKey(rand.Reader, DefaultCurve, nil)
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if err != nil {
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t.Fatal(err)
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}
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skLen := MaxSharedKeyLength(&prv1.PublicKey) / 2
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prv2, err := GenerateKey(rand.Reader, DefaultCurve, nil)
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if err != nil {
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t.Fatal(err)
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}
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sk1, err := prv1.GenerateShared(&prv2.PublicKey, skLen, skLen)
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if err != nil {
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t.Fatal(err)
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}
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sk2, err := prv2.GenerateShared(&prv1.PublicKey, skLen, skLen)
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if err != nil {
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t.Fatal(err)
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}
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if !bytes.Equal(sk1, sk2) {
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t.Fatal(ErrBadSharedKeys)
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}
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}
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func TestSharedKeyPadding(t *testing.T) {
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// sanity checks
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prv0 := hexKey("1adf5c18167d96a1f9a0b1ef63be8aa27eaf6032c233b2b38f7850cf5b859fd9")
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prv1 := hexKey("0097a076fc7fcd9208240668e31c9abee952cbb6e375d1b8febc7499d6e16f1a")
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x0, _ := new(big.Int).SetString("1a8ed022ff7aec59dc1b440446bdda5ff6bcb3509a8b109077282b361efffbd8", 16)
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x1, _ := new(big.Int).SetString("6ab3ac374251f638d0abb3ef596d1dc67955b507c104e5f2009724812dc027b8", 16)
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y0, _ := new(big.Int).SetString("e040bd480b1deccc3bc40bd5b1fdcb7bfd352500b477cb9471366dbd4493f923", 16)
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y1, _ := new(big.Int).SetString("8ad915f2b503a8be6facab6588731fefeb584fd2dfa9a77a5e0bba1ec439e4fa", 16)
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if prv0.PublicKey.X.Cmp(x0) != 0 {
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t.Errorf("mismatched prv0.X:\nhave: %x\nwant: %x\n", prv0.PublicKey.X.Bytes(), x0.Bytes())
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}
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if prv0.PublicKey.Y.Cmp(y0) != 0 {
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t.Errorf("mismatched prv0.Y:\nhave: %x\nwant: %x\n", prv0.PublicKey.Y.Bytes(), y0.Bytes())
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}
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if prv1.PublicKey.X.Cmp(x1) != 0 {
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t.Errorf("mismatched prv1.X:\nhave: %x\nwant: %x\n", prv1.PublicKey.X.Bytes(), x1.Bytes())
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}
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if prv1.PublicKey.Y.Cmp(y1) != 0 {
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t.Errorf("mismatched prv1.Y:\nhave: %x\nwant: %x\n", prv1.PublicKey.Y.Bytes(), y1.Bytes())
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}
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// test shared secret generation
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sk1, err := prv0.GenerateShared(&prv1.PublicKey, 16, 16)
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if err != nil {
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t.Log(err.Error())
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}
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sk2, err := prv1.GenerateShared(&prv0.PublicKey, 16, 16)
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if err != nil {
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t.Fatal(err.Error())
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}
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if !bytes.Equal(sk1, sk2) {
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t.Fatal(ErrBadSharedKeys.Error())
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}
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}
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// Verify that the key generation code fails when too much key data is
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// requested.
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func TestTooBigSharedKey(t *testing.T) {
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prv1, err := GenerateKey(rand.Reader, DefaultCurve, nil)
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if err != nil {
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t.Fatal(err)
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}
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prv2, err := GenerateKey(rand.Reader, DefaultCurve, nil)
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if err != nil {
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t.Fatal(err)
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}
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_, err = prv1.GenerateShared(&prv2.PublicKey, 32, 32)
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if err != ErrSharedKeyTooBig {
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t.Fatal("ecdh: shared key should be too large for curve")
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}
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_, err = prv2.GenerateShared(&prv1.PublicKey, 32, 32)
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if err != ErrSharedKeyTooBig {
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t.Fatal("ecdh: shared key should be too large for curve")
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}
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}
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// Benchmark the generation of P256 keys.
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func BenchmarkGenerateKeyP256(b *testing.B) {
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for i := 0; i < b.N; i++ {
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if _, err := GenerateKey(rand.Reader, elliptic.P256(), nil); err != nil {
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b.Fatal(err)
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}
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}
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}
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// Benchmark the generation of P256 shared keys.
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func BenchmarkGenSharedKeyP256(b *testing.B) {
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prv, err := GenerateKey(rand.Reader, elliptic.P256(), nil)
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if err != nil {
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b.Fatal(err)
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}
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b.ResetTimer()
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for i := 0; i < b.N; i++ {
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_, err := prv.GenerateShared(&prv.PublicKey, 16, 16)
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if err != nil {
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b.Fatal(err)
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}
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}
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}
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// Benchmark the generation of S256 shared keys.
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func BenchmarkGenSharedKeyS256(b *testing.B) {
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prv, err := GenerateKey(rand.Reader, crypto.S256(), nil)
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if err != nil {
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b.Fatal(err)
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}
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b.ResetTimer()
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for i := 0; i < b.N; i++ {
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_, err := prv.GenerateShared(&prv.PublicKey, 16, 16)
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if err != nil {
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b.Fatal(err)
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}
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}
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}
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// Verify that an encrypted message can be successfully decrypted.
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func TestEncryptDecrypt(t *testing.T) {
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prv1, err := GenerateKey(rand.Reader, DefaultCurve, nil)
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if err != nil {
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t.Fatal(err)
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}
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prv2, err := GenerateKey(rand.Reader, DefaultCurve, nil)
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if err != nil {
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t.Fatal(err)
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}
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message := []byte("Hello, world.")
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ct, err := Encrypt(rand.Reader, &prv2.PublicKey, message, nil, nil)
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if err != nil {
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t.Fatal(err)
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}
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pt, err := prv2.Decrypt(ct, nil, nil)
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if err != nil {
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t.Fatal(err)
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}
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if !bytes.Equal(pt, message) {
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t.Fatal("ecies: plaintext doesn't match message")
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}
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_, err = prv1.Decrypt(ct, nil, nil)
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if err == nil {
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t.Fatal("ecies: encryption should not have succeeded")
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}
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}
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func TestDecryptShared2(t *testing.T) {
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prv, err := GenerateKey(rand.Reader, DefaultCurve, nil)
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if err != nil {
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t.Fatal(err)
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}
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message := []byte("Hello, world.")
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shared2 := []byte("shared data 2")
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ct, err := Encrypt(rand.Reader, &prv.PublicKey, message, nil, shared2)
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if err != nil {
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t.Fatal(err)
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}
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// Check that decrypting with correct shared data works.
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pt, err := prv.Decrypt(ct, nil, shared2)
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if err != nil {
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t.Fatal(err)
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}
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if !bytes.Equal(pt, message) {
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t.Fatal("ecies: plaintext doesn't match message")
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}
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// Decrypting without shared data or incorrect shared data fails.
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if _, err = prv.Decrypt(ct, nil, nil); err == nil {
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t.Fatal("ecies: decrypting without shared data didn't fail")
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}
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if _, err = prv.Decrypt(ct, nil, []byte("garbage")); err == nil {
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t.Fatal("ecies: decrypting with incorrect shared data didn't fail")
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}
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}
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type testCase struct {
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Curve elliptic.Curve
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Name string
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Expected *ECIESParams
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}
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var testCases = []testCase{
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{
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Curve: elliptic.P256(),
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Name: "P256",
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Expected: ECIES_AES128_SHA256,
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},
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{
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Curve: elliptic.P384(),
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Name: "P384",
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Expected: ECIES_AES256_SHA384,
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},
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{
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Curve: elliptic.P521(),
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Name: "P521",
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Expected: ECIES_AES256_SHA512,
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},
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}
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// Test parameter selection for each curve, and that P224 fails automatic
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// parameter selection (see README for a discussion of P224). Ensures that
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// selecting a set of parameters automatically for the given curve works.
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func TestParamSelection(t *testing.T) {
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for _, c := range testCases {
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testParamSelection(t, c)
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}
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}
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func testParamSelection(t *testing.T, c testCase) {
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params := ParamsFromCurve(c.Curve)
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if params == nil {
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t.Fatal("ParamsFromCurve returned nil")
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} else if params != nil && !cmpParams(params, c.Expected) {
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t.Fatalf("ecies: parameters should be invalid (%s)\n", c.Name)
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}
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prv1, err := GenerateKey(rand.Reader, DefaultCurve, nil)
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if err != nil {
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t.Fatalf("%s (%s)\n", err.Error(), c.Name)
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}
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prv2, err := GenerateKey(rand.Reader, DefaultCurve, nil)
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if err != nil {
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t.Fatalf("%s (%s)\n", err.Error(), c.Name)
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}
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message := []byte("Hello, world.")
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ct, err := Encrypt(rand.Reader, &prv2.PublicKey, message, nil, nil)
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if err != nil {
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t.Fatalf("%s (%s)\n", err.Error(), c.Name)
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}
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pt, err := prv2.Decrypt(ct, nil, nil)
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if err != nil {
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t.Fatalf("%s (%s)\n", err.Error(), c.Name)
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}
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if !bytes.Equal(pt, message) {
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t.Fatalf("ecies: plaintext doesn't match message (%s)\n", c.Name)
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}
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_, err = prv1.Decrypt(ct, nil, nil)
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if err == nil {
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t.Fatalf("ecies: encryption should not have succeeded (%s)\n", c.Name)
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}
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}
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// Ensure that the basic public key validation in the decryption operation
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// works.
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func TestBasicKeyValidation(t *testing.T) {
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badBytes := []byte{0, 1, 5, 6, 7, 8, 9}
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prv, err := GenerateKey(rand.Reader, DefaultCurve, nil)
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if err != nil {
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t.Fatal(err)
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}
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message := []byte("Hello, world.")
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ct, err := Encrypt(rand.Reader, &prv.PublicKey, message, nil, nil)
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if err != nil {
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t.Fatal(err)
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}
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for _, b := range badBytes {
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ct[0] = b
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_, err := prv.Decrypt(ct, nil, nil)
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if err != ErrInvalidPublicKey {
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t.Fatal("ecies: validated an invalid key")
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}
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}
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}
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func TestBox(t *testing.T) {
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prv1 := hexKey("4b50fa71f5c3eeb8fdc452224b2395af2fcc3d125e06c32c82e048c0559db03f")
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prv2 := hexKey("d0b043b4c5d657670778242d82d68a29d25d7d711127d17b8e299f156dad361a")
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pub2 := &prv2.PublicKey
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message := []byte("Hello, world.")
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ct, err := Encrypt(rand.Reader, pub2, message, nil, nil)
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if err != nil {
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t.Fatal(err)
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}
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pt, err := prv2.Decrypt(ct, nil, nil)
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if err != nil {
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t.Fatal(err)
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}
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if !bytes.Equal(pt, message) {
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t.Fatal("ecies: plaintext doesn't match message")
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}
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if _, err = prv1.Decrypt(ct, nil, nil); err == nil {
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t.Fatal("ecies: encryption should not have succeeded")
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}
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}
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// Verify GenerateShared against static values - useful when
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// debugging changes in underlying libs
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func TestSharedKeyStatic(t *testing.T) {
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prv1 := hexKey("7ebbc6a8358bc76dd73ebc557056702c8cfc34e5cfcd90eb83af0347575fd2ad")
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prv2 := hexKey("6a3d6396903245bba5837752b9e0348874e72db0c4e11e9c485a81b4ea4353b9")
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skLen := MaxSharedKeyLength(&prv1.PublicKey) / 2
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sk1, err := prv1.GenerateShared(&prv2.PublicKey, skLen, skLen)
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if err != nil {
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t.Fatal(err)
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}
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sk2, err := prv2.GenerateShared(&prv1.PublicKey, skLen, skLen)
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if err != nil {
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t.Fatal(err)
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}
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if !bytes.Equal(sk1, sk2) {
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t.Fatal(ErrBadSharedKeys)
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}
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sk := decode("167ccc13ac5e8a26b131c3446030c60fbfac6aa8e31149d0869f93626a4cdf62")
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if !bytes.Equal(sk1, sk) {
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t.Fatalf("shared secret mismatch: want: %x have: %x", sk, sk1)
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}
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}
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func hexKey(prv string) *PrivateKey {
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key, err := crypto.HexToECDSA(prv)
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if err != nil {
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panic(err)
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}
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return ImportECDSA(key)
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}
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func decode(s string) []byte {
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bytes, err := hex.DecodeString(s)
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if err != nil {
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panic(err)
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}
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return bytes
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}
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