Can one compute TupleHash (SHA-3 derived function) in .NET using just .NET API?

[Carti-it]

Hi everyone,

I know that one can compute TupleHash (see) using the BouncyCastle:

<PackageVersion Include="BouncyCastle.Cryptography" Version="2.6.2 " />

and then doing something like this:

using Org.BouncyCastle.Crypto.Digests;

// ...

var tupleHash = new TupleHash(bitLength: 128, S: Customization);
tupleHash.BlockUpdate(something);

var digestSize = tupleHash.GetDigestSize();
var hash = new byte[digestSize];
tupleHash.DoFinal(hash, 0);

I wonder if one can compute the hash using just .NET API (without relying¹ on BouncyCastle.Cryptography).

Thank you

Footnotes

1. No, there is nothing wrong with the library. ↩

[teo-tsirpanis]

Implementing TupleHash using BCL APIs is not currently possible, because it requires cSHAKE, which is not available.

Supporting cSHAKE in .NET would require platform support in at least two of Windows, OpenSSL, Apple, or Android crypto APIs. It is available on Windows, but not yet on other platforms (see openssl/openssl#28358).

[teo-tsirpanis]

On second look, OpenSSL did add support for cSHAKE in version 4, due to be released in April, which allows TupleHash APIs to be added to .NET.

Opened a proposal in #125890.