blockchain-cryptography

blockchain-cryptography is a skill for Claude Code, Codex from j4flmao/agent-skills. It costs 201 tokens per session (8,325 once invoked), scanned A, original, MIT.

A guide to cryptography used in blockchain systems, including hashes, digital signatures, key derivation, Merkle trees, and zero-knowledge proofs. Merkle trees let systems verify data using compact proofs; zero-knowledge proofs verify claims without revealing the underlying data.

In plain words
What is it for?
Use it to design wallets, signing systems, multi-signature schemes, blockchain proofs, key derivation, and cryptographic tests.
Why use it?
It helps select compatible cryptographic methods and avoid errors involving keys, signatures, curves, nonces, and proof systems.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions Codex.

Good fit Use it to design wallets, signing systems, multi-signature schemes, blockchain proofs, key derivation, and cryptographic tests.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/j4flmao/agent-skills/blockchain-cryptography
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 j4flmao/agent-skills --skill blockchain-cryptography
Clone the repo
git clone --depth 1 https://github.com/j4flmao/agent-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 blockchain-cryptography

README.md
[![agentmods](https://agentmods.dev/badge/skills/j4flmao/agent-skills/blockchain-cryptography/github.svg)](https://agentmods.dev/skills/j4flmao/agent-skills/blockchain-cryptography)
Your own site
<a href="https://agentmods.dev/skills/j4flmao/agent-skills/blockchain-cryptography"><img src="https://agentmods.dev/badge/skills/j4flmao/agent-skills/blockchain-cryptography/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 blockchain-cryptography

Your own site · 80×15
<a href="https://agentmods.dev/skills/j4flmao/agent-skills/blockchain-cryptography"><img src="https://agentmods.dev/badge/skills/j4flmao/agent-skills/blockchain-cryptography.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 201 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 8,325 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. 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 $0.00201 $0.08325
Opus 5 $0.00101 $0.04163
Sonnet 5 $0.00040 $0.01665
Haiku 4.5 $0.00020 $0.00833

Measured 8d ago against content hash 23ed5702a7be, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

blockchain-cryptography 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 8d 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/blockchain/blockchain-cryptography/SKILL.md · 641 lines

How it starts

The opening of the file, as written. The whole thing — 641 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Blockchain Cryptography

Purpose

Guide the selection, implementation, and optimization of cryptographic primitives specific to blockchain systems. This skill enforces correct curve selection, signature scheme choice, and key management practices across all major blockchain protocols.

Agent Protocol

Trigger

"blockchain cryptography", "elliptic curve", "secp256k1", "BN254", "BLS", "Ed25519", "hash function blockchain", "Keccak-256", "SHA-256 blockchain", "Poseidon hash", "Merkle tree", "Merkle Patricia Trie", "Sparse Merkle Tree", "Verkle Trie", "ECDSA", "Schnorr signature", "BLS signature", "threshold signature", "FROST", "multi-sig", "aggregate signature", "zero-knowledge", "zk-SNARK", "zk-STARK", "Bulletproof", "circom", "Halo2", "BIP-32", "BIP-39", "BIP-44", "BIP-340", "PSBT", "BIP-174", "HD wallet", "key derivation", "cryptographic primitive", "signature scheme", "pairing-based cryptography", "post-quantum", "ecrecover", "EIP-712", "EIP-191", "RFC 6979", "KAT", "known-answer test", "nonce reuse", "signature malleability", "MuSig2", "threshold signing", "DKLs", "CGGMP", "aggregate signature", "hash-to-curve", "ICP", "Internet Computer"

Input Context

  • Cryptographic operation (signing, verification, hashing, proof generation)
  • Blockchain platform (Ethereum/Bitcoin/Solana/Cosmos)
  • Security level requirement (128-bit / 192-bit / 256-bit)
  • Performance constraints (verification throughput, gas budget)
  • Key management model (single key, HD wallet, multi-sig, threshold)
  • Threat model (passive/active, quantum-resistant needed?)

Output Artifact

Cryptographic architecture specification including:

  • Selected primitives with curve/parameter justifications
  • Implementation approach with library recommendations
  • Security analysis with known attack vectors and mitigations
  • Performance benchmarks and optimization strategies

Response Format

  1. Cryptographic primitive: curve/hash/scheme + security level + performance characteristics
  2. Blockchain usage: where and how this primitive is used in real blockchain networks
  3. Implementation details: algorithm specifics, edge cases, optimization techniques
  4. Security considerations: known attacks, parameter choices, implementation pitfalls

Read the full file on GitHub · 641 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. 8d ago First seen · 641 lines · 201 tokens per session scan A 23ed5702a7be

Subscribe to this mod's changes

blockchain-cryptography is a skill published in the GitHub repository j4flmao/agent-skills (23 stars, last pushed 5d ago), licensed MIT. It adds 201 tokens to every session and 8,325 once invoked, about $0.0010 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 2026-09-03.

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