1# Authentication — .NET SDK Quick Reference
2 
3> Condensed from **azure-identity-dotnet**. Full patterns (ASP.NET DI,
4> sovereign clouds, brokered auth, certificate credentials)
5> in the **azure-identity-dotnet** plugin skill if installed.
6 
7## Install
8dotnet add package Azure.Identity
9 
10## Quick Start
11> **Auth:** `DefaultAzureCredential` is for local development. See [auth-best-practices.md](../auth-best-practices.md) for production patterns.
12 
13```csharp
14using Azure.Identity;
15var credential = new DefaultAzureCredential();
16```
17 
18## Best Practices
19- Use DefaultAzureCredential for **local development only**. In production, use deterministic credentials (ManagedIdentityCredential) — see [auth-best-practices.md](../auth-best-practices.md)
20- Reuse credential instances — single instance shared across clients
21- Configure retry policies for credential operations
22- Enable logging with AzureEventSourceListener for debugging auth issues
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