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.
git clone --depth 1 https://github.com/j4flmao/agent-skillsWrote 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.
[](https://agentmods.dev/rules/j4flmao/agent-skills/crypto-deprecation)<a href="https://agentmods.dev/rules/j4flmao/agent-skills/crypto-deprecation"><img src="https://agentmods.dev/badge/rules/j4flmao/agent-skills/crypto-deprecation/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.
<a href="https://agentmods.dev/rules/j4flmao/agent-skills/crypto-deprecation"><img src="https://agentmods.dev/badge/rules/j4flmao/agent-skills/crypto-deprecation.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00022 | $0.00365 |
| Opus 5.5 | $0.00009 | $0.00146 |
| Sonnet 5.5 | $0.00004 | $0.00073 |
| Haiku 4.5 | $0.00002 | $0.00036 |
Grade A, and why
crypto-deprecation 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 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.
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.
What it actually says
Cryptographic Deprecation & Safety
Cursor/AI MUST follow these rules when writing code that involves hashing, encryption, or digital signatures.
1. Strictly Forbidden Hash Functions
- Rule: NEVER generate code using
MD5orSHA-1. They are cryptographically broken and vulnerable to collision attacks. - Action: Default to
SHA-256,SHA-384, orSHA-3.
2. Forbidden Asymmetric Encryption
- Rule: NEVER generate
RSA-1024keys. They are trivially crackable. - Rule: Avoid generating raw RSA without padding. Always enforce
OAEPpadding for RSA encryption andPSSpadding for signatures. - Action: Prefer Elliptic Curve Cryptography (
Ed25519,X25519) over RSA for new implementations due to better performance and security, UNLESS Post-Quantum algorithms are explicitly requested.
3. Post-Quantum Awareness (AES-256)
- Rule: When implementing symmetric encryption for highly sensitive data, default to
AES-256-GCMrather thanAES-128. Grover's algorithm halves the effective security bit-strength of symmetric ciphers.AES-256retains 128 bits of post-quantum security.
4. Password Hashing
- Rule: NEVER use standard cryptographic hashes (SHA-256) for passwords.
- Action: You MUST use computationally expensive key derivation functions:
Argon2id(Primary choice),scrypt, orbcrypt.
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.
- 1mo ago First seen · 25 lines · 22 tokens per session scan A 827c6f8f2780
crypto-deprecation is a cursor rule published in the GitHub repository j4flmao/agent-skills (33 stars, last pushed 10d ago), licensed MIT. It adds 22 tokens to every session and 365 once invoked, about $0.0001 per session on Opus 5.5. 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 2026-09-05.
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