# Code signing

Canonical page: /glossary/code-signing

API keys & secrets glossary, macOS Keychain & security. Code Signing: How macOS Verifies an App's Identity

**Short answer:** Code signing is the process of attaching a cryptographic signature to an app, tied to a developer's Apple Developer ID, so macOS can verify the app has not been altered since it was signed and can confirm who built it.

## Why it matters

Code signing is also how the Keychain decides which apps are allowed to access a given entry without prompting every time, since access rules can be tied to a signed app's identity rather than just its name.

## In Claude Keychain

Claude Keychain is signed with a real Apple Developer ID, which is part of what lets it request Keychain access like any other legitimate Mac app, rather than triggering the warnings unsigned software gets.

## Common questions

**Is a signed app automatically safe?**

Signing verifies identity and integrity, not intent, so it confirms who built the app, not that the app is trustworthy.

**What happens if a signed app is modified after signing?**

macOS detects the mismatch and will refuse to run it or will warn you, depending on the type of change.

## Related

[Notarization (macOS)](/glossary/notarization), [App Sandbox](/glossary/app-sandbox), [Entitlements (macOS)](/glossary/entitlements)