john

john is a skill for Claude Code, Codex from killvxk/malskills-zh. It costs 67 tokens per session (474 once invoked), scanned A, original, no licence file.

A CPU-based offline password-hashing recovery tool that supports many hash formats, wordlists, transformation rules, and gradually increasing brute-force attempts. A hash is a one-way representation commonly used to store passwords.

In plain words
What is it for?
It is for authorised password recovery, security testing, and auditing of password hashes using dictionaries, rules, or incremental guessing.
Why use it?
It helps test or recover passwords when a GPU is unavailable by trying organised candidate passwords locally.

Skill for Claude CodeCodex

Part of the malskills-zh plugin — 56 skills shipped together

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/killvxk/malskills-zh/john
Any agent
npx skills add killvxk/malskills-zh --skill john
Clone the repo
git clone --depth 1 https://github.com/killvxk/malskills-zh

Made for: Claude Code, Codex.

Or install malskills-zh, the plugin that ships this one along with the rest of its 56 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for john

README.md
[![agentmods](https://agentmods.dev/badge/skills/killvxk/malskills-zh/john.svg)](https://agentmods.dev/skills/killvxk/malskills-zh/john)
Your own site
<a href="https://agentmods.dev/skills/killvxk/malskills-zh/john"><img src="https://agentmods.dev/badge/skills/killvxk/malskills-zh/john.svg" alt="Measured on agentmods" height="20"></a>
Per session 67 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 474 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin unknown No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00067 $0.00474
Opus 5 $0.00034 $0.00237
Sonnet 5 $0.00013 $0.00095
Haiku 4.5 $0.00007 $0.00047

Measured 4d ago against content hash 58f0a588fafd, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

john scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/john/SKILL.md · 65 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 4d ago First seen · 65 lines · 67 tokens per session scan A 58f0a588fafd

Subscribe to this mod's changes

john is a skill published in the GitHub repository killvxk/malskills-zh (6 stars, last pushed 5mo ago), with no licence file. It adds 67 tokens to every session and 474 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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