Add Blake2b intrinsics POC

[TimothyMakkison]

Adapted @saucecontrol's Blake2Fast intrinsics code to work with the Konscious.Security.Cryptography library and thought it would work here.

The benchmark measured a 6x-13x speed up without additional memory usage. Blake2s or Blake2xs would probably experience similar benefits.

Non intrinsics

Method	Size	Mean	Error	StdDev	Median	Gen0	Allocated
GetHash	3	2.270 μs	0.0804 μs	0.2372 μs	2.337 μs	0.1106	176 B
GetHash	100	2.082 μs	0.0241 μs	0.0214 μs	2.083 μs	0.1106	176 B
GetHash	1000	15.085 μs	0.8234 μs	2.4279 μs	15.903 μs	0.0916	176 B
GetHash	10000	155.035 μs	2.8955 μs	4.1527 μs	155.360 μs	-	176 B

Intrinsics

Method	Size	Mean	Error	StdDev	Median	Gen0	Allocated
GetHash	3	356.7 ns	11.23 ns	33.12 ns	367.6 ns	0.1121	176 B
GetHash	100	341.0 ns	6.96 ns	20.09 ns	343.6 ns	0.1121	176 B
GetHash	1000	1,439.0 ns	27.08 ns	22.61 ns	1,434.5 ns	0.1106	176 B
GetHash	10000	12,796.6 ns	259.71 ns	765.76 ns	13,144.9 ns	0.1068	176 B

Note that I'm new to intrinsics and CompilerServices.Unsafe, this shouldn't be considered complete or safe. Do you have a CI pipeline for testing intrinsic code?

[peterdettman]

Great numbers, but suggest the following changes:

• Move all intrinsics code to a separate file (Blake2b_X86).
• Put intrinsics code under "#if NETCOREAPP3_0_OR_GREATER", which AFAIK is the correct minimal version.
• Add a licensing comment if the code is a substantial copy of either of the mentioned projects.
• Add IsSupported method to the new class and use that from Blake2bDigest
• Extract round function into a method (AggressiveInlining is still fine)
• Probably can replace most of the Unsafe methods with MemoryMarshal methods

At least add the license comment, the rest I can take care of if necessary.

[TimothyMakkison]

• Move all intrinsics code to a separate file (Blake2b_X86).
• Put intrinsics code under "#if NETCOREAPP3_0_OR_GREATER", which AFAIK is the correct minimal version.
• Add a licensing comment if the code is a substantial copy of either of the mentioned projects.
• Add IsSupported method to the new class and use that from Blake2bDigest
• Extract round function into a method (AggressiveInlining is still fine)
• Probably can replace most of the Unsafe methods with MemoryMarshal methods

Added Blake2s_X86.

Blake2s

Non intrinsics

Method	Size	Mean	Error	StdDev	Median	Gen0	Allocated
GetHash	3	1.872 μs	0.0935 μs	0.2758 μs	1.987 μs	0.1450	232 B
GetHash	100	3.686 μs	0.0737 μs	0.1523 μs	3.720 μs	0.1450	232 B
GetHash	1000	28.101 μs	0.5315 μs	1.0857 μs	28.234 μs	0.1221	232 B
GetHash	10000	204.365 μs	9.7001 μs	28.6010 μs	200.846 μs	-	232 B

Intrinsics

Method	Size	Mean	Error	StdDev	Gen0	Allocated
GetHash	3	347.4 ns	13.51 ns	39.85 ns	0.1478	232 B
GetHash	100	501.3 ns	12.88 ns	37.99 ns	0.1478	232 B
GetHash	1000	2,545.4 ns	38.75 ns	34.35 ns	0.1450	232 B
GetHash	10000	23,501.2 ns	465.85 ns	653.06 ns	0.1221	232 B

Blake2xs

Non intrinsics

Method	Size	Mean	Error	StdDev	Gen0	Allocated
GetHash	3	2.306 μs	0.0315 μs	0.0295 μs	0.5684	896 B
GetHash	100	3.201 μs	0.0413 μs	0.0366 μs	0.5684	896 B
GetHash	1000	15.635 μs	0.1960 μs	0.1834 μs	0.5493	896 B
GetHash	10000	135.593 μs	1.6090 μs	1.5051 μs	0.4883	896 B

Intrinsics

Method	Size	Mean	Error	StdDev	Median	Gen0	Allocated
GetHash	3	1.072 μs	0.0193 μs	0.0198 μs	1.070 μs	0.5703	896 B
GetHash	100	1.091 μs	0.0307 μs	0.0906 μs	1.109 μs	0.5703	896 B
GetHash	1000	2.858 μs	0.1685 μs	0.4969 μs	3.035 μs	0.5684	896 B
GetHash	10000	16.398 μs	0.1364 μs	0.1675 μs	16.444 μs	0.5493	896 B

There was no overlap between Blake2b and Blake2s so I deleted VectorExtensions and inlined the methods.

Suggestions

Add a length check to DoFinal to ensure that output spans and arrays are long enough.

There are several repeat implementations of Store128, Load128, Store128_UInt32, perhaps a shared helper method would help.

[peterdettman]

Note that intrinsics aren't available for NETSTANDARD2_1_OR_GREATER, so those directives should be removed (just NETCOREAPP3_0_OR_GREATER).

I'd still like methods on the _X86 classes, e.g.:
public static bool IsSupported => Avx2.IsSupported && BitConverter.IsLittleEndian;

although ideally BitConverter.IsLittleEndian isn't a requirement and only affects Load/Store (this could fall out later when I factor out all the load/store methods and support bigendian).

Also if all the rounds have the same structure (or a small set thereof), please factor out a method for 1 round (using ref parameters where each round applies to different parts of the state).

I've added length checks that you suggested also (this mirror can take a few days to be updated though).

[TimothyMakkison]

• Note that intrinsics aren't available for NETSTANDARD2_1_OR_GREATER, so those directives should be removed (just NETCOREAPP3_0_OR_GREATER).
• I'd still like methods on the _X86 classes, e.g.:

public static bool IsSupported => Avx2.IsSupported && BitConverter.IsLittleEndian;

Also if all the rounds have the same structure (or a small set thereof), please factor out a method for 1 round (using ref parameters where each round applies to different parts of the state).

I've created a Round function containing the diagonalization and G calls, The remaining logic is loading the b0-b4 values, as far as I can tell this can't be fruther simplified as each round is subtly different.

I've added length checks that you suggested also (this mirror can take a few days to be updated though).

Thanks, it was driving me nuts when debugging the benchmarks

Should I update the xml documentation? It looks like the docs haven't been updated since being converted from java. Are you okay with using <inheritdoc />?

/// <inheritdoc />
public void Update(byte b)
{

[TimothyMakkison]

I've converted the javadocs to xml form. I've used <inheritdoc /> where possible and added summaries when the existing javadoc differed from the IDigest description.

Nitpick: I've noticed that a couple of functions such as Update(byte b) have different parameter names to the interface IDigest Update(byte input). I haven't altered the names as this would be a breaking change, but it might be worth updating them to match the interface.

[peterdettman]

Is this ready for review/merge?

[TimothyMakkison]

I'll hold off for and convert this to a draft. Want to double check I haven't added a regression for .Net 3