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Snake&Apple II—Code Signing

Karol Mazurek

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How the Code Signing works & how to read the Code Signature on macOS.

INTRO

Welcome to another article in the series on macOS security internals!

This article provides in-depth information about the Code Signature format and introduces how the Code Signing works. You will learn here:

  • How to determine if a file has a valid Signature
  • Where the entitlements and requirements are stored
  • Low-level format of all Code Signature elements
  • The concept of ad hoc signing and public key cryptography
  • ASN.1 format and much more…

Additionally, this article will explain how to extract important information from Code Signature in human-readable form using Python and other tools.

Please note that some topics have been intentionally omitted and will be addressed in future articles. However, leave a comment if you have any questions or need clarification about anything written here while reading. I guarantee a response and will use your feedback for future articles.

The Snake&Apple II. Code Signing repository contains all of the code used.

Code Signing

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