PostQuantum.SecretSharing.Extensions 2.2.0

.NET 8.0 This package targets .NET 8.0. The package is compatible with this framework or higher. 
dotnet add package PostQuantum.SecretSharing.Extensions --version 2.2.0
                    


                    

                
NuGet\Install-Package PostQuantum.SecretSharing.Extensions -Version 2.2.0
This command is intended to be used within the Package Manager Console in Visual Studio, as it uses the NuGet module's version of Install-Package. 
<PackageReference Include="PostQuantum.SecretSharing.Extensions" Version="2.2.0" />
For projects that support PackageReference, copy this XML node into the project file to reference the package. 
<PackageVersion Include="PostQuantum.SecretSharing.Extensions" Version="2.2.0" />
                    


                            Directory.Packages.props
                        

                    

                
<PackageReference Include="PostQuantum.SecretSharing.Extensions" />
                    


                            Project file
For projects that support Central Package Management (CPM), copy this XML node into the solution Directory.Packages.props file to version the package. 
paket add PostQuantum.SecretSharing.Extensions --version 2.2.0
                    


                    

                
#r "nuget: PostQuantum.SecretSharing.Extensions, 2.2.0"
#r directive can be used in F# Interactive and Polyglot Notebooks. Copy this into the interactive tool or source code of the script to reference the package. 
#:package PostQuantum.SecretSharing.Extensions@2.2.0
#:package directive can be used in C# file-based apps starting in .NET 10 preview 4. Copy this into a .cs file before any lines of code to reference the package. 
#addin nuget:?package=PostQuantum.SecretSharing.Extensions&version=2.2.0
                    


                            Install as a Cake Addin
                        

                    

                
#tool nuget:?package=PostQuantum.SecretSharing.Extensions&version=2.2.0
                    


                            Install as a Cake Tool

PostQuantum.SecretSharing.Extensions

Opt-in higher-level ceremony helpers for PostQuantum.SecretSharing. Like the core, this package has no third-party runtime dependency.

The first helper is distributed proactive secret sharing: re-randomize a K-of-N sharing so that shares from an earlier epoch become useless — without ever reconstructing the secret. This defeats a mobile adversary that compromises different trustees over time, and unlike the core's Refresh (which briefly reconstructs and re-splits), the secret is never formed in memory.

Re-randomize without reconstructing (co-located)

using PostQuantum.SecretSharing;
using PostQuantum.SecretSharing.Extensions;

SecretShare[] shares = ShamirSecretSharing.Split(secret, new SharePolicy(3, 5));

// New epoch: shares are re-randomized; the secret never appears in memory.
SecretShare[] refreshed = ProactiveRefresh.RefreshLocally(shares);

// Old shares no longer combine with new ones; any 3 refreshed shares still recover the secret.

Distributed protocol (multi-party, no trusted machine)

int[] parties = shares.Select(s => s.ShareIndex).ToArray();

// 1. Each party publishes a contribution (one sub-share per recipient) and delivers each
//    sub-share point-to-point — NOT broadcast.
IReadOnlyList<RefreshSubShare> mine = ProactiveRefresh.CreateContribution(
    contributorIndex: myIndex, threshold: 3, secretLength: secret.Length, recipientIndices: parties);

// 2. Each party applies the sub-shares addressed to it, yielding its refreshed share.
SecretShare refreshedMine = ProactiveRefresh.Apply(myShare, subSharesAddressedToMe);

The honest tradeoff

This is the honest-but-curious construction:

  • Secrecy is preserved against a minority adversary, and the secret is never reconstructed.
  • It does not prove a contributor used a zero constant term, so a malicious contributor could corrupt (never learn) the secret. Corruption is detected: the secret is unchanged, so the preserved check value fails at the next reconstruction — reject the round and keep the old shares.

Full design, protocol, and limitations: docs/PROACTIVE-REFRESH.md.

Documentation

Product Compatible and additional computed target framework versions.
.NET net8.0 is compatible.  net8.0-android was computed.  net8.0-browser was computed.  net8.0-ios was computed.  net8.0-maccatalyst was computed.  net8.0-macos was computed.  net8.0-tvos was computed.  net8.0-windows was computed.  net9.0 was computed.  net9.0-android was computed.  net9.0-browser was computed.  net9.0-ios was computed.  net9.0-maccatalyst was computed.  net9.0-macos was computed.  net9.0-tvos was computed.  net9.0-windows was computed.  net10.0 is compatible.  net10.0-android was computed.  net10.0-browser was computed.  net10.0-ios was computed.  net10.0-maccatalyst was computed.  net10.0-macos was computed.  net10.0-tvos was computed.  net10.0-windows was computed. 
Compatible target framework(s)
Included target framework(s) (in package)
Learn more about Target Frameworks and .NET Standard.

NuGet packages

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Version Downloads Last Updated
2.2.0 96 6/14/2026