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AI Primer

constant-time-testing

trailofbitsby trailofbits5 months ago7.2k

Measures timing side channels in cryptographic implementations by running them, using dudect for statistical analysis and Timecop over Valgrind for dynamic tracing. Covers the formal, symbolic, dynamic, and statistical tool categories and how to read a result. Use when testing whether a running implementation is constant-time, measuring timing variance on a compiled binary, or investigating a suspected timing attack. Not for statically inspecting compiler output — the constant-time-analysis plugin covers that.

Install

npx skills add https://github.com/trailofbits/skills --skill constant-time-testing
Show step-by-step
  1. 1

    Open your terminal

    • Mac: Press ⌘ Space, type "Terminal", press Enter
    • Windows: Press Win R, type "cmd", press Enter
  2. 2

    Paste the command above and press Enter

    Use the Copy command button, then paste in your terminal (Mac: ⌘V, Windows: Ctrl V).

  3. 3

    Restart Claude Code

    Close and reopen Claude Code, or start a new session, so it picks up the new skill.

Where it lives
~/.claude/skills/trailofbits--skills--plugins--testing-handbook-skills--skills--constant-time-testing/
├── SKILL.md
└── ... (skill resource files)
View on GitHub

Always review skill code before installing. Third-party skills may contain scripts that run on your machine.

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