crypto

crypto is a skill for Claude Code, Codex from arbazkhan971/godmode. It costs 30 tokens per session (2,061 once invoked), scanned A, original, MIT.

Guidance for using cryptography to protect data and verify identity. It covers password hashing, encryption, digital signatures, key management, signed tokens, and secure network connections.

In plain words
What is it for?
Use it when handling personal, financial, or health data; storing passwords; setting up TLS; signing JWTs; managing keys; encrypting information; or creating digital signatures.
Why use it?
It helps avoid unsafe algorithms, weak password storage, exposed keys, and poorly configured HTTPS or token signing. It also connects cryptographic choices to the type of data being protected.

Skill for Claude CodeCodex

Part of the godmode plugin — 133 skills, 1 command, 9 agents, 3 MCP servers 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/arbazkhan971/godmode/crypto
Any agent
npx skills add arbazkhan971/godmode --skill crypto
Clone the repo
git clone --depth 1 https://github.com/arbazkhan971/godmode

Made for: Claude Code, Codex.

Or install godmode, the plugin that ships this one along with the rest of its 133 skills, 1 command, 9 agents, 3 MCP servers.

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 crypto

README.md
[![agentmods](https://agentmods.dev/badge/skills/arbazkhan971/godmode/crypto.svg)](https://agentmods.dev/skills/arbazkhan971/godmode/crypto)
Your own site
<a href="https://agentmods.dev/skills/arbazkhan971/godmode/crypto"><img src="https://agentmods.dev/badge/skills/arbazkhan971/godmode/crypto.svg" alt="Measured on agentmods" height="20"></a>
Per session 30 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,061 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original 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 5.1 $0.00030 $0.02061
Opus 5 $0.00015 $0.01030
Sonnet 5 $0.00006 $0.00412
Haiku 4.5 $0.00003 $0.00206

Measured 5d ago against content hash eeeaa27babba, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

crypto 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 5d 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/crypto/SKILL.md · 181 lines

How it starts

The opening of the file, as written. The whole thing — 181 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Crypto — Cryptography Implementation

Activate When

  • User invokes /godmode:crypto
  • User says "encryption", "hashing", "password storage", "bcrypt", "argon2"
  • User says "key management", "digital signature", "JWT signing"
  • User says "TLS setup", "HTTPS configuration", "certificate"
  • When code handles sensitive data (PII, financial, health records)

Workflow

Step 1: Requirements Assessment

Classify data: at rest (passwords, PII, financial, API keys), in transit (TLS, mTLS, DB connections), integrity (signatures, HMAC, checksums), compliance (PCI-DSS, HIPAA, GDPR, FIPS).

Step 2: Algorithm Selection

Password hashing: Argon2id (m=65536, t=3, p=4) primary. bcrypt (cost 12+) fallback. NEVER MD5, SHA1, SHA256, PBKDF2 (<100K iter).

Symmetric encryption: AES-256-GCM (AEAD, general). ChaCha20-Poly1305 (software-fast). NEVER ECB, DES, 3DES, RC4, AES-CBC without HMAC.

Asymmetric: X25519 (key exchange). RSA-OAEP 2048+ (encryption). NEVER PKCS1v1.5 or RSA <2048.

Signatures: Ed25519 (primary). RS256/ES256 (JWT). NEVER RSA PKCS1v1.5 sigs, DSA.

Hashing (non-password): SHA-256 (general). BLAKE3 (modern). HMAC-SHA-256 (keyed). NEVER MD5, SHA-1.

Key derivation: Argon2id (from password). HKDF-SHA-256 (from shared secret).

Random: CSPRNG only (crypto.randomBytes, secrets, crypto/rand). NEVER Math.random().

Step 3: Encryption at Rest

Use envelope encryption: unique DEK per record (AES-256-GCM) encrypted by KEK from KMS. Store encrypted data + encrypted DEK + IV + auth tag. Unique 96-bit IV per operation. Master key in KMS. Track key version.

Database: TDE (physical theft) + column encryption (SQLi) + connection TLS (network).

Step 4: TLS Hardening

  • TLS 1.2 minimum, 1.3 preferred. Disable SSLv2/v3, TLS 1.0/1.1.
  • AEAD ciphers only (GCM, ChaCha20-Poly1305). ECDHE required (forward secrecy).
  • ECDSA P-256 or RSA 2048+ certs. OCSP stapling. HSTS with preload.
  • Test: ssllabs.com/ssltest (target A+).

Step 5: Password Hashing

Argon2id with auto-generated salt, constant-time comparison. Hash never encrypt. No length limits (allow 128+). Check breach lists. No composition rules (NIST 800-63B). Min 8 chars. Upgrade old hashes on login. Rate limit auth. Never log passwords.

Read the full file on GitHub · 181 lines

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. 5d ago First seen · 181 lines · 30 tokens per session scan A eeeaa27babba

Subscribe to this mod's changes

crypto is a skill published in the GitHub repository arbazkhan971/godmode (26 stars, last pushed 8d ago), licensed MIT. It adds 30 tokens to every session and 2,061 once invoked, about $0.0002 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 2026-08-30.

Related

Other skills, from other repositories

jobs-to-be-done

Discover what customers truly need by analyzing the "job" they hire your product to do. Use when the user mentions "customer discovery", "why customers churn", "what job does this solve", "competing against luck", "product-market fit", "switching behavior", "milkshake moment", or "functional vs emotional jobs". Also…

wondelai/skills · 137 tokens

asc-subscription-localization

Bulk-localize subscription, subscription-group, and in-app purchase display names across App Store locales using asc, including API 4.4.1 version-scoped v2 resources. Use when filling or updating subscription/IAP names and descriptions without App Store Connect UI work.

rorkai/app-store-connect-cli-skills · 60 tokens

codex

Run benchmark-selected GPT-5.6 work through the Codex CLI.

notque/vexjoy-agent · 18 tokens

agent-code-generator

Generates Agent definitions (.md files) based on user intent and standard templates.

majiayu000/claude-skill-registry · 20 tokens

scienceworld-growth-focuser

Use when you have planted a seed or need to track a plant's growth stage (sprouting, flowering, reproduction). Applies the 'focus on' action to a specific plant or biological entity to signal intent and monitor its development. Trigger after planting or when you need to observe life cycle progression in the…

zjunlp/SkillNet · 71 tokens

iterate-pivot-decision

Documents a strategic pivot or persevere decision with the evidence, analysis, and rationale. Use when evaluating whether to change direction on a product, feature, or strategy based on market feedback.

product-on-purpose/pm-skills · 43 tokens