public override KdfParameters GetDefaultParameters()
{
KdfParameters p = base.GetDefaultParameters();
p.SetUInt32(ParamVersion, MaxVersion);
p.SetUInt64(ParamIterations, DefaultIterations);
p.SetUInt64(ParamMemory, DefaultMemory);
p.SetUInt32(ParamParallelism, DefaultParallelism);
return(p);
}
public override KdfParameters GetDefaultParameters()
{
KdfParameters p = base.GetDefaultParameters();
p.SetUInt64(ParamRounds, PwDefs.DefaultKeyEncryptionRounds);
return(p);
}
protected void MaximizeParamUInt64(KdfParameters p, string strName,
ulong uMin, ulong uMax, uint uMilliseconds, bool bInterpSearch)
{
if (p == null)
{
Debug.Assert(false); return;
}
if (string.IsNullOrEmpty(strName))
{
Debug.Assert(false); return;
}
if (uMin > uMax)
{
Debug.Assert(false); return;
}
if (uMax > (ulong.MaxValue >> 1))
{
Debug.Assert(false);
uMax = ulong.MaxValue >> 1;
if (uMin > uMax)
{
p.SetUInt64(strName, uMin); return;
}
}
byte[] pbMsg = new byte[32];
for (int i = 0; i < pbMsg.Length; ++i)
{
pbMsg[i] = (byte)i;
}
ulong uLow = uMin;
ulong uHigh = uMin + 1UL;
long tLow = 0;
long tHigh = 0;
long tTarget = (long)uMilliseconds;
// Determine range
while (uHigh <= uMax)
{
p.SetUInt64(strName, uHigh);
// GC.Collect();
Stopwatch sw = Stopwatch.StartNew();
Transform(pbMsg, p);
sw.Stop();
tHigh = sw.ElapsedMilliseconds;
if (tHigh > tTarget)
{
break;
}
uLow = uHigh;
tLow = tHigh;
uHigh <<= 1;
}
if (uHigh > uMax)
{
uHigh = uMax; tHigh = 0;
}
if (uLow > uHigh)
{
uLow = uHigh; // Skips to end
}
// Find optimal number of iterations
while ((uHigh - uLow) >= 2UL)
{
ulong u = (uHigh + uLow) >> 1; // Binary search
// Interpolation search, if possible
if (bInterpSearch && (tLow > 0) && (tHigh > tTarget) &&
(tLow <= tTarget))
{
u = uLow + (((uHigh - uLow) * (ulong)(tTarget - tLow)) /
(ulong)(tHigh - tLow));
if ((u >= uLow) && (u <= uHigh))
{
u = Math.Max(u, uLow + 1UL);
u = Math.Min(u, uHigh - 1UL);
}
else
{
Debug.Assert(false);
u = (uHigh + uLow) >> 1;
}
}
p.SetUInt64(strName, u);
// GC.Collect();
Stopwatch sw = Stopwatch.StartNew();
Transform(pbMsg, p);
sw.Stop();
long t = sw.ElapsedMilliseconds;
if (t == tTarget)
{
uLow = u; break;
}
else if (t > tTarget)
{
uHigh = u; tHigh = t;
}
else
{
uLow = u; tLow = t;
}
}
p.SetUInt64(strName, uLow);
}
public override KdfParameters GetBestParameters(uint uMilliseconds)
{
KdfParameters p = GetDefaultParameters();
ulong uRounds;
#if !ModernKeePassLib
// Try native method
if (NativeLib.TransformKeyBenchmark256(uMilliseconds, out uRounds))
{
p.SetUInt64(ParamRounds, uRounds);
return(p);
}
#endif
if (TransformKeyBenchmarkGCrypt(uMilliseconds, out uRounds))
{
p.SetUInt64(ParamRounds, uRounds);
return(p);
}
byte[] pbKey = new byte[32];
byte[] pbNewKey = new byte[32];
for (int i = 0; i < pbKey.Length; ++i)
{
pbKey[i] = (byte)i;
pbNewKey[i] = (byte)i;
}
#if ModernKeePassLib || KeePassUAP
KeyParameter kp = new KeyParameter(pbKey);
AesEngine aes = new AesEngine();
aes.Init(true, kp);
#else
byte[] pbIV = new byte[16];
using (SymmetricAlgorithm a = CryptoUtil.CreateAes())
{
if (a.BlockSize != 128) // AES block size
{
Debug.Assert(false);
a.BlockSize = 128;
}
a.KeySize = 256;
a.Mode = CipherMode.ECB;
using (ICryptoTransform t = a.CreateEncryptor(pbKey, pbIV))
{
// !t.CanReuseTransform -- doesn't work with Mono
if ((t == null) || (t.InputBlockSize != 16) ||
(t.OutputBlockSize != 16))
{
Debug.Assert(false);
p.SetUInt64(ParamRounds, PwDefs.DefaultKeyEncryptionRounds);
return(p);
}
#endif
uRounds = 0;
int tStart = Environment.TickCount;
while (true)
{
for (ulong j = 0; j < BenchStep; ++j)
{
#if ModernKeePassLib || KeePassUAP
aes.ProcessBlock(pbNewKey, 0, pbNewKey, 0);
aes.ProcessBlock(pbNewKey, 16, pbNewKey, 16);
#else
t.TransformBlock(pbNewKey, 0, 16, pbNewKey, 0);
t.TransformBlock(pbNewKey, 16, 16, pbNewKey, 16);
#endif
}
uRounds += BenchStep;
if (uRounds < BenchStep) // Overflow check
{
uRounds = ulong.MaxValue;
break;
}
uint tElapsed = (uint)(Environment.TickCount - tStart);
if (tElapsed > uMilliseconds)
{
break;
}
}
p.SetUInt64(ParamRounds, uRounds);
#if ModernKeePassLib || KeePassUAP
aes.Reset();
#else
}
}
#endif
return(p);
}
