offensive-crypto-attacks

offensive-crypto-attacks is a skill for Claude Code, Codex from SnailSploit/Claude-Red. It costs 261 tokens per session (4,862 once invoked), scanned A, original, MIT.

A guide to finding and exploiting weaknesses in how applications use encryption, signed tokens, and hashes. It focuses on implementation mistakes rather than breaking the underlying mathematics.

In plain words
What is it for?
Use it to inspect cookies, tokens, API parameters, stored credentials, and signed URLs; identify the cryptographic design involved; test the weakness; and document its cause and fix.
Why use it?
It helps uncover flaws such as revealing whether encrypted data has valid padding, predictable encrypted blocks, weak message checks, or guessable random values.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to inspect cookies, tokens, API parameters, stored credentials, and signed URLs; identify the cryptographic design involved; test the weakness; and document its cause and fix.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/snailsploit/claude-red/offensive-crypto-attacks
About the project

claude-red is a library of structured skills that give Claude specialized offensive-security methods for areas such as web vulnerabilities, shellcode, exploit development, and identity systems. It is intended for authorized red-team work, bug-bounty triage, security research, CTF preparation, and operator training. Its catalogue contains the project's skills for loading these security specializations into Claude.

SnailSploit/Claude-Red · 7,620 stars · on GitHub

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.

Any agent
npx skills add SnailSploit/Claude-Red --skill offensive-crypto-attacks
Clone the repo
git clone --depth 1 https://github.com/SnailSploit/Claude-Red

Made for: Claude Code, Codex.

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 offensive-crypto-attacks

README.md
[![agentmods](https://agentmods.dev/badge/skills/snailsploit/claude-red/offensive-crypto-attacks/github.svg)](https://agentmods.dev/skills/snailsploit/claude-red/offensive-crypto-attacks)
Your own site
<a href="https://agentmods.dev/skills/snailsploit/claude-red/offensive-crypto-attacks"><img src="https://agentmods.dev/badge/skills/snailsploit/claude-red/offensive-crypto-attacks/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for offensive-crypto-attacks

Your own site · 80×15
<a href="https://agentmods.dev/skills/snailsploit/claude-red/offensive-crypto-attacks"><img src="https://agentmods.dev/badge/skills/snailsploit/claude-red/offensive-crypto-attacks.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 261 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,862 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 $0.00261 $0.04862
Opus 5.5 $0.00104 $0.01945
Sonnet 5.5 $0.00052 $0.00972
Haiku 4.5 $0.00026 $0.00486

Measured 1mo ago against content hash 75d97b1fa754, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

offensive-crypto-attacks scanned grade A with 1 finding 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 1mo 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

resp = requests.get(url, params={"data": payload})
Skills/crypto/offensive-crypto-attacks/SKILL.md · 477 lines

How it starts

The opening of the file, as written. The whole thing — 477 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Cryptographic Implementation Attacks

You are performing offensive cryptographic analysis against target applications. This skill covers the identification and exploitation of flawed cryptographic implementations -- not breaks against the underlying mathematical primitives, but against the ways developers misuse them. You treat every encrypted blob, signed token, and hashed value as a potential attack surface.

Quick Workflow

  1. Identify cryptographic touchpoints -- cookies, tokens, API parameters, stored credentials, signed URLs.
  2. Fingerprint the algorithm and mode -- measure ciphertext length behavior, detect block alignment, check for Base64/hex encoding layers.
  3. Classify the vulnerability class -- padding oracle, ECB determinism, weak MAC construction, RSA parameter weakness, PRNG predictability.
  4. Select and configure the appropriate tool or custom script.
  5. Execute the attack, decrypt or forge the target value.
  6. Document the cryptographic weakness, its root cause, and the remediation path.

Padding Oracle Attacks

Padding oracle attacks exploit systems that reveal whether CBC-mode decrypted plaintext has valid PKCS7 padding. A single bit of information -- valid or invalid padding -- is sufficient to decrypt any ciphertext block or forge arbitrary plaintext without knowing the key.

Identify the oracle by submitting modified ciphertext and observing differential responses. The oracle can manifest as distinct HTTP status codes, different error messages, timing differences, or behavioral changes in application logic.

Use padbuster for automated exploitation against web applications:

# Decrypt an encrypted cookie value
# URL is the endpoint, EncryptedValue is the target, BlockSize is typically 8 or 16
padbuster http://target.com/app?token=EncryptedValue EncryptedValue 16 \
  -cookies "session=EncryptedValue" \
  -encoding 0 \
  -error "invalid"

# Forge a new plaintext value using the discovered oracle
padbuster http://target.com/app?token=EncryptedValue EncryptedValue 16 \
  -cookies "session=EncryptedValue" \
  -encoding 0 \
  -error "invalid" \
  -plaintext "admin=true;user=attacker"

Read the full file on GitHub · 477 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. 1mo ago First seen · 477 lines · 261 tokens per session scan A 75d97b1fa754

Subscribe to this mod's changes

offensive-crypto-attacks is a skill published in the GitHub repository SnailSploit/Claude-Red (7,620 stars, last pushed 8d ago), licensed MIT. It adds 261 tokens to every session and 4,862 once invoked, about $0.0010 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). 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

app-store-opportunity-research

Full-pipeline iOS App Store opportunity research. Discovers underserved niches, analyzes competitor gaps, estimates revenue, produces scored top-3 opportunity reports, and writes MVP PRDs — all through browser and web research. Use when the user wants to find profitable iOS app ideas, research App Store charts…

robertguss/claude-code-toolkit · 130 tokens

ghost-writer

Produce first drafts that match a writer's authentic voice using their Voice DNA Document. Consumes DNA documents from writing-dna-discovery skill. Generates 2 meaningfully different drafts with headlines, confidence assessment, decision notes, and DNA refinement suggestions. Collaborative partner that evaluates…

robertguss/claude-code-toolkit · 77 tokens

voice-capture

This skill should be used when extracting voice profiles from sample text, creating voice documentation, or matching a specific writing style. It applies when users provide sample text and want to capture the voice for future use.

robertguss/claude-code-toolkit · 45 tokens

writing-orchestration

This skill should be used when orchestrating complex writing workflows with multiple phases. It provides two-agent orchestration patterns, the two-gate content readiness assessment, 10 baseline writing strategies, 20+ situational strategies, and quality checkpoints. Inspired by the Spiral Writing System.

robertguss/claude-code-toolkit · 60 tokens

brainstorm

Collaborative brainstorming partner for multi-session ideation projects. Use when the user wants to brainstorm, ideate, explore ideas, or think through problems—whether for SaaS products, software tools, book ideas, newsletter content, business strategies, or any creative/analytical challenge. Handles session…

robertguss/claude-code-toolkit · 91 tokens

dhh-writing

This skill should be used when writing in the distinctive style of David Heinemeier Hansson (DHH). It applies when creating blog posts, technical articles, business content, manifestos, or any prose requiring a clear, punchy, opinionated style.

robertguss/claude-code-toolkit · 56 tokens