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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
using System.IO;
using Test.Cryptography;
using Xunit;
namespace System.Security.Cryptography.Hashing.Algorithms.Tests
{
public abstract class HmacTests
{
// RFC2202 defines the test vectors for HMACMD5 and HMACSHA1
// RFC4231 defines the test vectors for HMACSHA{224,256,384,512}
// They share the same datasets for cases 1-5, but cases 6 and 7 differ.
private readonly byte[][] _testKeys;
private readonly byte[][] _testData;
protected HmacTests(byte[][] testKeys, byte[][] testData)
{
_testKeys = testKeys;
_testData = testData;
}
protected abstract HMAC Create();
protected abstract HashAlgorithm CreateHashAlgorithm();
protected abstract int BlockSize { get; }
protected void VerifyHmac(
int testCaseId,
string digest,
int truncateSize = -1)
{
byte[] digestBytes = ByteUtils.HexToByteArray(digest);
byte[] computedDigest;
using (HMAC hmac = Create())
{
Assert.True(hmac.HashSize > 0);
byte[] key = (byte[])_testKeys[testCaseId].Clone();
hmac.Key = key;
// make sure the getter returns different objects each time
Assert.NotSame(key, hmac.Key);
Assert.NotSame(hmac.Key, hmac.Key);
// make sure the setter didn't cache the exact object we passed in
key[0] = (byte)(key[0] + 1);
Assert.NotEqual<byte>(key, hmac.Key);
computedDigest = hmac.ComputeHash(_testData[testCaseId]);
}
if (truncateSize != -1)
{
byte[] tmp = new byte[truncateSize];
Array.Copy(computedDigest, 0, tmp, 0, truncateSize);
computedDigest = tmp;
}
Assert.Equal(digestBytes, computedDigest);
}
protected void VerifyHmacRfc2104_2()
{
// Ensure that keys shorter than the threshold don't get altered.
using (HMAC hmac = Create())
{
byte[] key = new byte[BlockSize];
hmac.Key = key;
byte[] retrievedKey = hmac.Key;
Assert.Equal<byte>(key, retrievedKey);
}
// Ensure that keys longer than the threshold are adjusted via Rfc2104 Section 2.
using (HMAC hmac = Create())
{
byte[] overSizedKey = new byte[BlockSize + 1];
hmac.Key = overSizedKey;
byte[] actualKey = hmac.Key;
byte[] expectedKey = CreateHashAlgorithm().ComputeHash(overSizedKey);
Assert.Equal<byte>(expectedKey, actualKey);
// Also ensure that the hashing operation uses the adjusted key.
byte[] data = new byte[100];
hmac.Key = expectedKey;
byte[] expectedHash = hmac.ComputeHash(data);
hmac.Key = overSizedKey;
byte[] actualHash = hmac.ComputeHash(data);
Assert.Equal<byte>(expectedHash, actualHash);
}
}
[Fact]
public void InvalidInput_Null()
{
using (HMAC hash = Create())
{
Assert.Throws<ArgumentNullException>("buffer", () => hash.ComputeHash((byte[])null));
Assert.Throws<ArgumentNullException>("buffer", () => hash.ComputeHash(null, 0, 0));
Assert.Throws<NullReferenceException>(() => hash.ComputeHash((Stream)null));
}
}
[Fact]
public void InvalidInput_NegativeOffset()
{
using (HMAC hash = Create())
{
Assert.Throws<ArgumentOutOfRangeException>("offset", () => hash.ComputeHash(Array.Empty<byte>(), -1, 0));
}
}
[Fact]
public void InvalidInput_NegativeCount()
{
using (HMAC hash = Create())
{
Assert.Throws<ArgumentException>(null, () => hash.ComputeHash(Array.Empty<byte>(), 0, -1));
}
}
[Fact]
public void InvalidInput_TooBigOffset()
{
using (HMAC hash = Create())
{
Assert.Throws<ArgumentException>(null, () => hash.ComputeHash(Array.Empty<byte>(), 1, 0));
}
}
[Fact]
public void InvalidInput_TooBigCount()
{
byte[] nonEmpty = new byte[53];
using (HMAC hash = Create())
{
Assert.Throws<ArgumentException>(null, () => hash.ComputeHash(nonEmpty, 0, nonEmpty.Length + 1));
Assert.Throws<ArgumentException>(null, () => hash.ComputeHash(nonEmpty, 1, nonEmpty.Length));
Assert.Throws<ArgumentException>(null, () => hash.ComputeHash(nonEmpty, 2, nonEmpty.Length - 1));
Assert.Throws<ArgumentException>(null, () => hash.ComputeHash(Array.Empty<byte>(), 0, 1));
}
}
[Fact]
public void BoundaryCondition_Count0()
{
byte[] nonEmpty = new byte[53];
using (HMAC hash = Create())
{
byte[] emptyHash = hash.ComputeHash(Array.Empty<byte>());
byte[] shouldBeEmptyHash = hash.ComputeHash(nonEmpty, nonEmpty.Length, 0);
Assert.Equal(emptyHash, shouldBeEmptyHash);
shouldBeEmptyHash = hash.ComputeHash(nonEmpty, 0, 0);
Assert.Equal(emptyHash, shouldBeEmptyHash);
nonEmpty[0] = 0xFF;
nonEmpty[nonEmpty.Length - 1] = 0x77;
shouldBeEmptyHash = hash.ComputeHash(nonEmpty, nonEmpty.Length, 0);
Assert.Equal(emptyHash, shouldBeEmptyHash);
shouldBeEmptyHash = hash.ComputeHash(nonEmpty, 0, 0);
Assert.Equal(emptyHash, shouldBeEmptyHash);
}
}
[Fact]
public void OffsetAndCountRespected()
{
byte[] dataA = { 1, 1, 2, 3, 5, 8 };
byte[] dataB = { 0, 1, 1, 2, 3, 5, 8, 13 };
using (HMAC hash = Create())
{
byte[] baseline = hash.ComputeHash(dataA);
// Skip the 0 byte, and stop short of the 13.
byte[] offsetData = hash.ComputeHash(dataB, 1, dataA.Length);
Assert.Equal(baseline, offsetData);
}
}
}
}
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