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Merge pull request #166 from dorssel/pbkdf2
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Add PBKDF2-AES-CMAC-PRF-128
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@dorssel
dorssel authored Jan 17, 2025
2 parents 1b2db27 + 4e5fb85 commit c9aa527
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Showing 11 changed files with 835 additions and 33 deletions.
4 changes: 3 additions & 1 deletion .github/linters/vs-spell-exclusion.txt
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Original file line number Diff line number Diff line change
@@ -1,13 +1,15 @@
accum
bitand
Cmac
CMAC
Codecov
Decryptor
Dorssel
dotnet
Encryptor
inliner
Intelli
Mbed
netstandard
NIST
PBKDF
xorend
321 changes: 314 additions & 7 deletions AesExtra/AesCmacPrf128.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,9 @@
//
// SPDX-License-Identifier: MIT

using System.Security.Cryptography;
using System.Text;

namespace Dorssel.Security.Cryptography;

/// <summary>
Expand All @@ -15,6 +18,46 @@ namespace Dorssel.Security.Cryptography;
public static class AesCmacPrf128
{
const int BLOCKSIZE = 16; // bytes
readonly static byte[] BlockOfZeros = new byte[BLOCKSIZE];

static AesCmac UncheckedCreateKeyedPrf(byte[] key)
{
var prf = new AesCmac();
if (key.Length != BLOCKSIZE)
{
using var blockSizedKey = new SecureByteArray(BLOCKSIZE);
prf.Key = BlockOfZeros;
prf.UncheckedHashCore(key);
prf.UncheckedHashFinal(blockSizedKey);
prf.Initialize();
prf.Key = blockSizedKey;
}
else
{
prf.Key = key;
}
return prf;
}

static AesCmac UncheckedCreateKeyedPrf(ReadOnlySpan<byte> key)
{
var prf = new AesCmac();
if (key.Length != BLOCKSIZE)
{
using var blockSizedKey = new SecureByteArray(BLOCKSIZE);
prf.Key = BlockOfZeros;
prf.UncheckedHashCore(key);
prf.UncheckedHashFinal(blockSizedKey);
prf.Initialize();
prf.Key = blockSizedKey;
}
else
{
using var blockSizedKey = new SecureByteArray(key);
prf.Key = blockSizedKey;
}
return prf;
}

/// <summary>
/// TODO
Expand All @@ -34,8 +77,10 @@ public static byte[] DeriveKey(byte[] inputKey, byte[] message)
throw new ArgumentNullException(nameof(inputKey));
}

using var cmac = UncheckedCreateKeyedPrf(inputKey);
var destination = new byte[BLOCKSIZE];
DeriveKey(inputKey, message, destination);
cmac.UncheckedHashCore(message);
cmac.UncheckedHashFinal(destination);
return destination;
}

Expand All @@ -54,15 +99,277 @@ public static int DeriveKey(ReadOnlySpan<byte> inputKey, ReadOnlySpan<byte> mess
throw new ArgumentException("Destination is too short.");
}

if (inputKey.Length == BLOCKSIZE)
using var cmac = UncheckedCreateKeyedPrf(inputKey);
cmac.UncheckedHashCore(message);
cmac.UncheckedHashFinal(destination);
return BLOCKSIZE;
}

static void UncheckedPbkdf2(AesCmac cmac, ReadOnlySpan<byte> salt, Span<byte> destination, int iterations)
{
// i
Span<byte> INT_i = [0, 0, 0, 1];

Span<byte> U = stackalloc byte[BLOCKSIZE];
Span<byte> F = stackalloc byte[BLOCKSIZE];

// i from 1 to l
while (destination.Length > 0)
{
return AesCmac.HashData(inputKey, message, destination);
// j = 1
// U_1 = PRF (P, S || INT (i))
cmac.Initialize();
cmac.UncheckedHashCore(salt);
cmac.UncheckedHashCore(INT_i);
cmac.UncheckedHashFinal(U);
// F (P, S, c, i) = U_1 \xor U_2 \xor ... \xor U_c
U.CopyTo(F);
// j from 2 to c
for (var j = 2; j <= iterations; j++)
{
// U = PRF (P, U_{j-1})
cmac.Initialize();
cmac.UncheckedHashCore(U);
cmac.UncheckedHashFinal(U);
// F (P, S, c, i) = U_1 \xor U_2 \xor ... \xor U_c
F.xor_InPlace(U);
}
if (destination.Length < BLOCKSIZE)
{
break;
}
// DK = T_1 || T_2 || ... || T_l<0..r-1>
// where T_i = F (P, S, c, i)
F.CopyTo(destination);
destination = destination[BLOCKSIZE..];
INT_i.BigEndianIncrement();
}
else
// T_l<0..r-1>, if r != 0, where T_l = F (P, S, c, l)
F[..destination.Length].CopyTo(destination);

CryptographicOperations.ZeroMemory(U);
CryptographicOperations.ZeroMemory(F);
}

/// <summary>
/// TODO
/// </summary>
/// <param name="password">TODO</param>
/// <param name="salt">TODO</param>
/// <param name="iterations">TODO</param>
/// <param name="outputLength">TODO</param>
/// <returns>TODO</returns>
/// <exception cref="ArgumentNullException">TODO</exception>
/// <exception cref="ArgumentOutOfRangeException">TODO</exception>
public static byte[] Pbkdf2(byte[] password, byte[] salt, int iterations, int outputLength)
{
if (password == null)
{
throw new ArgumentNullException(nameof(password));
}
if (salt == null)
{
throw new ArgumentNullException(nameof(password));
}
if (iterations <= 0)
{
throw new ArgumentOutOfRangeException(nameof(iterations));
}
if (outputLength < 0)
{
throw new ArgumentOutOfRangeException(nameof(outputLength));
}

if (outputLength == 0)
{
return [];
}

var destination = new byte[outputLength];
using var cmac = UncheckedCreateKeyedPrf(password);
UncheckedPbkdf2(cmac, salt, destination, iterations);
return destination;
}

/// <summary>
/// TODO
/// </summary>
/// <param name="password">TODO</param>
/// <param name="salt">TODO</param>
/// <param name="iterations">TODO</param>
/// <param name="outputLength">TODO</param>
/// <returns>TODO</returns>
/// <exception cref="ArgumentOutOfRangeException">TODO</exception>
public static byte[] Pbkdf2(ReadOnlySpan<byte> password, ReadOnlySpan<byte> salt, int iterations, int outputLength)
{
if (iterations <= 0)
{
throw new ArgumentOutOfRangeException(nameof(iterations));
}
if (outputLength < 0)
{
throw new ArgumentOutOfRangeException(nameof(outputLength));
}

if (outputLength == 0)
{
return [];
}

var destination = new byte[outputLength];
using var cmac = UncheckedCreateKeyedPrf(password);
UncheckedPbkdf2(cmac, salt, destination, iterations);
return destination;
}

/// <summary>
/// TODO
/// </summary>
/// <param name="password">TODO</param>
/// <param name="salt">TODO</param>
/// <param name="destination">TODO</param>
/// <param name="iterations">TODO</param>
/// <exception cref="ArgumentOutOfRangeException">TODO</exception>
public static void Pbkdf2(ReadOnlySpan<byte> password, ReadOnlySpan<byte> salt, Span<byte> destination, int iterations)
{
if (iterations <= 0)
{
throw new ArgumentOutOfRangeException(nameof(iterations));
}

if (destination.Length == 0)
{
return;
}

using var cmac = UncheckedCreateKeyedPrf(password);
UncheckedPbkdf2(cmac, salt, destination, iterations);
}

static SecureByteArray PasswordAsBytes(string password)
{
var encoding = new UTF8Encoding(false, true);
var byteCount = encoding.GetByteCount(password);
var secureByteArray = new SecureByteArray(byteCount);
_ = encoding.GetBytes(password, 0, password.Length, secureByteArray, 0);
return secureByteArray;
}

static SecureByteArray PasswordAsBytes(ReadOnlySpan<char> password)
{
var encoding = new UTF8Encoding(false, true);
var passwordAsChars = password.ToArray();
try
{
var byteCount = encoding.GetByteCount(passwordAsChars);
var secureByteArray = new SecureByteArray(byteCount);
_ = encoding.GetBytes(passwordAsChars, 0, password.Length, secureByteArray, 0);
return secureByteArray;
}
finally
{
for (var i = 0; i < passwordAsChars.Length; i++)
{
passwordAsChars[i] = '\0';
}
}
}

/// <summary>
/// TODO
/// </summary>
/// <param name="password">TODO</param>
/// <param name="salt">TODO</param>
/// <param name="iterations">TODO</param>
/// <param name="outputLength">TODO</param>
/// <returns>TODO</returns>
/// <exception cref="ArgumentNullException">TODO</exception>
/// <exception cref="ArgumentOutOfRangeException">TODO</exception>
public static byte[] Pbkdf2(string password, byte[] salt, int iterations, int outputLength)
{
if (password == null)
{
throw new ArgumentNullException(nameof(password));
}
using var passwordAsBytes = PasswordAsBytes(password);
if (salt == null)
{
throw new ArgumentNullException(nameof(password));
}
if (iterations <= 0)
{
throw new ArgumentOutOfRangeException(nameof(iterations));
}
if (outputLength < 0)
{
throw new ArgumentOutOfRangeException(nameof(outputLength));
}

if (outputLength == 0)
{
using var K = new SecureByteArray(BLOCKSIZE);
_ = AesCmac.HashData(new byte[BLOCKSIZE], inputKey, K);
return AesCmac.HashData(K, message, destination);
return [];
}

var destination = new byte[outputLength];
using var cmac = UncheckedCreateKeyedPrf(passwordAsBytes);
UncheckedPbkdf2(cmac, salt, destination, iterations);
return destination;
}

/// <summary>
/// TODO
/// </summary>
/// <param name="password">TODO</param>
/// <param name="salt">TODO</param>
/// <param name="iterations">TODO</param>
/// <param name="outputLength">TODO</param>
/// <returns>TODO</returns>
/// <exception cref="ArgumentOutOfRangeException">TODO</exception>
public static byte[] Pbkdf2(ReadOnlySpan<char> password, ReadOnlySpan<byte> salt, int iterations, int outputLength)
{
using var passwordAsBytes = PasswordAsBytes(password);
if (iterations <= 0)
{
throw new ArgumentOutOfRangeException(nameof(iterations));
}
if (outputLength < 0)
{
throw new ArgumentOutOfRangeException(nameof(outputLength));
}

if (outputLength == 0)
{
return [];
}

var destination = new byte[outputLength];
using var cmac = UncheckedCreateKeyedPrf(passwordAsBytes);
UncheckedPbkdf2(cmac, salt, destination, iterations);
return destination;
}

/// <summary>
/// TODO
/// </summary>
/// <param name="password">TODO</param>
/// <param name="salt">TODO</param>
/// <param name="destination">TODO</param>
/// <param name="iterations">TODO</param>
/// <exception cref="ArgumentOutOfRangeException">TODO</exception>
public static void Pbkdf2(ReadOnlySpan<char> password, ReadOnlySpan<byte> salt, Span<byte> destination, int iterations)
{
using var passwordAsBytes = PasswordAsBytes(password);
if (iterations <= 0)
{
throw new ArgumentOutOfRangeException(nameof(iterations));
}

if (destination.Length == 0)
{
return;
}

using var cmac = UncheckedCreateKeyedPrf(passwordAsBytes);
UncheckedPbkdf2(cmac, salt, destination, iterations);
}
}
9 changes: 1 addition & 8 deletions AesExtra/AesCtrTransform.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -86,14 +86,7 @@ void UncheckedTransformSingleBlock(ReadOnlySpan<byte> inputBlock, Span<byte> des
destination[i] = (byte)(inputBlock[i] ^ XorBlock[i]);
}

// Increment counter
for (var i = Counter.Length - 1; i >= 0; --i)
{
if (unchecked(++Counter[i]) != 0)
{
break;
}
}
Counter.AsSpan().BigEndianIncrement();
}

internal void UncheckedTransform(ReadOnlySpan<byte> input, Span<byte> destination)
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