How I built tamper-proof audit trails for AI decisions in .NET

A developer has released AiTrace.NET, an open-source .NET library that creates tamper-proof audit trails for AI decisions by hashing each record and chaining it to the previous one. The library, available as a NuGet package, targets teams in regulated industries needing cryptographic proof of AI outputs. Future Pro features include RSA-SHA256 signatures and compliance reports.

Every time your app calls an LLM, a question hangs in the air: if something goes wrong, can you prove exactly what happened? Not a log file. Not a database record someone could edit. Actual cryptographic proof. That is the problem I built AiTrace.NET to solve. The problem with regular logging Application logs are great until they become evidence. A log file can be edited, deleted, or backdated. When a client disputes an AI-generated output, a timestamp in a database means nothing without proof of integrity. What AiTrace does differently Each decision record gets SHA-256 hashed. The hash of the previous record is embedded in the next one, creating a chain. Break the chain by modifying or removing any record, and verification fails immediately. js // 1. Register in ASP.NET Core builder.Services.AddAiTrace o = { o.StoreContent = true; o.BasicRedaction = true; } ; // 2. Inject and log a decision public class DecisionService IAuditStore store { public async Task LogAsync { await store.LogDecisionAsync new AiDecision { Prompt = "Summarize the contract.", Output = "The contract covers...", Model = "gpt-4o", UserId = "user-42" } ; } } One NuGet package. No external service. No database required. Records are plain JSON files in a local folder you control. dotnet add package AiTrace --prerelease Who this is for Any .NET team using LLMs in a context where auditability matters: legal tech, fintech, healthcare, insurance, or any regulated space where "the AI said so" is not an acceptable answer. What is next The Pro tier adds RSA-SHA256 signatures per record, compliance reports, and sealed evidence bundles ready for legal review. The core package is MIT, open source, and free forever. GitHub: https://github.com/aitrace-dotnet/AiTrace.NET https://github.com/aitrace-dotnet/AiTrace.NET NuGet: https://www.nuget.org/packages/AiTrace/0.1.0-preview.10 https://www.nuget.org/packages/AiTrace/0.1.0-preview.10 Docs: https://aitrace-dotnet.github.io/AiTrace.NET/ https://aitrace-dotnet.github.io/AiTrace.NET/