cryptographic-failures

cryptographic-failures is a skill for Claude Code, Codex from scholarly360/owasp-top10-web-skills. It costs 125 tokens per session (2,476 once invoked), scanned A, original, MIT.

A Python security-audit guide for cryptographic failures in FastAPI and Flask applications. Cryptography protects data and secrets, and this guide covers mistakes in password hashing, randomness, encryption, JWTs, hardcoded keys, and TLS certificates.

In plain words
What is it for?
Use it to review password storage, random-value generation, secret handling, JWT settings, encryption modes, and SSL/TLS verification.
Why use it?
It helps find weak or misused security protections that can expose passwords, secrets, or network traffic. It also identifies common unsafe Python patterns and suggests safer alternatives.

Skill for Claude CodeCodex

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

Good fit Use it to review password storage, random-value generation, secret handling, JWT settings, encryption modes, and SSL/TLS verification.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/scholarly360/owasp-top10-web-skills/cryptographic-failures
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 scholarly360/owasp-top10-web-skills --skill cryptographic-failures
Clone the repo
git clone --depth 1 https://github.com/scholarly360/owasp-top10-web-skills

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 cryptographic-failures

README.md
[![agentmods](https://agentmods.dev/badge/skills/scholarly360/owasp-top10-web-skills/cryptographic-failures/github.svg)](https://agentmods.dev/skills/scholarly360/owasp-top10-web-skills/cryptographic-failures)
Your own site
<a href="https://agentmods.dev/skills/scholarly360/owasp-top10-web-skills/cryptographic-failures"><img src="https://agentmods.dev/badge/skills/scholarly360/owasp-top10-web-skills/cryptographic-failures/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 cryptographic-failures

Your own site · 80×15
<a href="https://agentmods.dev/skills/scholarly360/owasp-top10-web-skills/cryptographic-failures"><img src="https://agentmods.dev/badge/skills/scholarly360/owasp-top10-web-skills/cryptographic-failures.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 125 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,476 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.
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 $0.00125 $0.02476
Opus 5 $0.00063 $0.01238
Sonnet 5 $0.00025 $0.00495
Haiku 4.5 $0.00013 $0.00248

Measured 11d ago against content hash 9a9fbe61074b, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

cryptographic-failures 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 11d 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.

requests.get(url, verify=False)
skills/cryptographic-failures/SKILL.md · 267 lines

How it starts

The opening of the file, as written. The whole thing — 267 lines — stays where its author put it; the contents beside it link to each section on GitHub.

A04:2025 — Cryptographic Failures

OWASP Rank: #4 (dropped from #2 due to improved TLS adoption) Incidence: 3.80% of applications, 1.6M+ occurrences, 32 CWEs

Cryptographic Failures cover the absence, misuse, or weakness of cryptography protecting data at rest and in transit. In Python, there is a distinctive set of pitfalls that differ from Java/.NET.


What This Skill Covers

Area Key Risk Python-Specific Pitfall
Password hashing Weak/missing algorithm Using hashlib.md5/sha1 instead of bcrypt/Argon2
Randomness Predictable values import random instead of import secrets
Hardcoded keys Key leakage SECRET_KEY = "..." literals in source
TLS/SSL Cert bypass verify=False in requests/httpx
JWT secrets Key strength/algorithm Weak secret, missing algo pinning
Symmetric encryption Deprecated modes ECB mode, no authenticated encryption

Step-by-Step Audit Workflow

1. Static Scan with Bandit

Run Bandit — the primary Python SAST tool for catching crypto issues automatically:

pip install bandit
bandit -r . -t B303,B304,B305,B306,B311,B324,B501,B502,B503,B504,B505,B506 -f json -o bandit_crypto.json

Key Bandit test IDs for cryptographic failures:

Bandit ID What It Catches Severity
B303 MD5/SHA1 usage Medium
B304/B305 Weak cipher modes (ECB, DES) High
B311 random module in security context Low
B324 Hashlib use of weak hash Medium
B501 verify=False in SSL context High
B502/B503/B504 Insecure SSL/TLS versions Medium–High
B105/B106 Hardcoded password/secret Medium

2. Manual Code Pattern Review

Work through these patterns in priority order:

🔴 CRITICAL — Password Hashing
# BAD — MD5/SHA1 for passwords: CWE-328, CWE-759, CWE-916
hashlib.md5(password.encode()).hexdigest()
hashlib.sha1(password.encode()).hexdigest()
hashlib.sha256(password.encode()).hexdigest()  # also bad — no salt, no stretching

# GOOD — use passlib with bcrypt or argon2
from passlib.context import CryptContext
pwd_context = CryptContext(schemes=["argon2"], deprecated="auto")
# OR
pwd_context = CryptContext(schemes=["bcrypt"], bcrypt__rounds=12, deprecated="auto")
hashed = pwd_context.hash(plain_password)

Read the full file on GitHub · 267 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 11d ago First seen · 267 lines · 125 tokens per session scan A 9a9fbe61074b

Subscribe to this mod's changes

cryptographic-failures is a skill published in the GitHub repository scholarly360/owasp-top10-web-skills (22 stars, last pushed 5mo ago), licensed MIT. It adds 125 tokens to every session and 2,476 once invoked, about $0.0006 per session on Opus 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.

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