/// <summary>
/// Gets the secondary hash algorithm used for pool mixing, serving roughly analogous
/// to key whitening.
/// </summary>
/// <returns>A hash algorithm suitable for the current platform serving as the
/// secondary hash algorithm for pool mixing, or null if no secondary hash
/// algorithm can be used (e.g. due to FIPS algorithm restrictions)</returns>
/// <remarks>The instance returned need not be freed as it is cached.</remarks>
private static HashAlgorithm GetSecondaryHash()
{
if (HasSecondaryHashAlgorithm)
{
return(SecondaryHashAlgorithmCache);
}
HashFactoryDelegate[] priorityList = new HashFactoryDelegate[] {
delegate() { return(new RIPEMD160Managed()); }
};
foreach (HashFactoryDelegate func in priorityList)
{
try
{
SecondaryHashAlgorithmCache = func();
break;
}
catch (PlatformNotSupportedException)
{
}
catch (InvalidOperationException)
{
}
}
HasSecondaryHashAlgorithm = true;
return(SecondaryHashAlgorithmCache);
}
/// <summary>
/// Gets the primary hash algorithm used for pool mixing.
/// </summary>
/// <returns>A hash algorithm suitable for the current platform serving as the
/// primary hash algorithm for pool mixing.</returns>
/// <remarks>The instance returned need not be freed as it is cached.</remarks>
private static HashAlgorithm GetPrimaryHash()
{
if (PrimaryHashAlgorithmCache != null)
{
return(PrimaryHashAlgorithmCache);
}
HashFactoryDelegate[] priorityList = new HashFactoryDelegate[] {
delegate() { return(new SHA512Cng()); },
delegate() { return(new SHA512CryptoServiceProvider()); },
delegate() { return(new SHA512Managed()); },
delegate() { return(new SHA256Cng()); },
delegate() { return(new SHA256CryptoServiceProvider()); },
delegate() { return(new SHA256Managed()); },
delegate() { return(new SHA1Cng()); },
delegate() { return(new SHA1CryptoServiceProvider()); },
delegate() { return(new SHA1Managed()); }
};
foreach (HashFactoryDelegate func in priorityList)
{
try
{
return(PrimaryHashAlgorithmCache = func());
}
catch (PlatformNotSupportedException)
{
}
catch (InvalidOperationException)
{
}
}
throw new InvalidOperationException(S._("No suitable hash algorithms were found " +
"on this computer."));
}
