Crypto Audit
briiirussell/cybersecurity-skills
Audit cryptography implementation — algorithm choice, key sizes, KDF parameters, IV/nonce handling, signature verification, randomness, TLS configuration, and key rotation.
Agent skill
Implementing Digital Signatures With Ed25519
Implements digital signatures using the Ed25519 algorithm (Curve25519), covering key-pair generation, signing, signature verification, and security tradeoffs versus RSA and ECDSA.
Install Implementing Digital Signatures With Ed25519
$ npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill implementing-digital-signatures-with-ed25519 -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install mukul975/Anthropic-Cybersecurity-Skills implementing-digital-signatures-with-ed25519 --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/mukul975/Anthropic-Cybersecurity-Skills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/implementing-digital-signatures-with-ed25519 .claude/skills/implementing-digital-signatures-with-ed25519 && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "implementing-digital-signatures-with-ed25519" agent skill from https://github.com/mukul975/Anthropic-Cybersecurity-Skills/tree/main/skills/implementing-digital-signatures-with-ed25519 into .claude/skills/implementing-digital-signatures-with-ed25519/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "implementing-digital-signatures-with-ed25519", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/mukul975/Anthropic-Cybersecurity-Skills/tree/main/skills/implementing-digital-signatures-with-ed25519Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill implementing-digital-signatures-with-ed25519 -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install mukul975/Anthropic-Cybersecurity-Skills implementing-digital-signatures-with-ed25519 --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/mukul975/Anthropic-Cybersecurity-Skills.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/implementing-digital-signatures-with-ed25519 .agents/skills/implementing-digital-signatures-with-ed25519 && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "implementing-digital-signatures-with-ed25519" agent skill from https://github.com/mukul975/Anthropic-Cybersecurity-Skills/tree/main/skills/implementing-digital-signatures-with-ed25519 into .agents/skills/implementing-digital-signatures-with-ed25519/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "implementing-digital-signatures-with-ed25519", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill implementing-digital-signatures-with-ed25519 -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install mukul975/Anthropic-Cybersecurity-Skills implementing-digital-signatures-with-ed25519 --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/mukul975/Anthropic-Cybersecurity-Skills.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/implementing-digital-signatures-with-ed25519 .cursor/skills/implementing-digital-signatures-with-ed25519 && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "implementing-digital-signatures-with-ed25519" agent skill from https://github.com/mukul975/Anthropic-Cybersecurity-Skills/tree/main/skills/implementing-digital-signatures-with-ed25519 into .cursor/skills/implementing-digital-signatures-with-ed25519/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "implementing-digital-signatures-with-ed25519", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/mukul975/Anthropic-Cybersecurity-Skills.git --path skills/implementing-digital-signatures-with-ed25519--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill implementing-digital-signatures-with-ed25519 -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install mukul975/Anthropic-Cybersecurity-Skills implementing-digital-signatures-with-ed25519 --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/mukul975/Anthropic-Cybersecurity-Skills.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/implementing-digital-signatures-with-ed25519 .gemini/skills/implementing-digital-signatures-with-ed25519 && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "implementing-digital-signatures-with-ed25519" agent skill from https://github.com/mukul975/Anthropic-Cybersecurity-Skills/tree/main/skills/implementing-digital-signatures-with-ed25519 into .gemini/skills/implementing-digital-signatures-with-ed25519/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "implementing-digital-signatures-with-ed25519", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install mukul975/Anthropic-Cybersecurity-Skills implementing-digital-signatures-with-ed25519Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill implementing-digital-signatures-with-ed25519 -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/mukul975/Anthropic-Cybersecurity-Skills.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/implementing-digital-signatures-with-ed25519 .github/skills/implementing-digital-signatures-with-ed25519 && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "implementing-digital-signatures-with-ed25519" agent skill from https://github.com/mukul975/Anthropic-Cybersecurity-Skills/tree/main/skills/implementing-digital-signatures-with-ed25519 into .github/skills/implementing-digital-signatures-with-ed25519/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "implementing-digital-signatures-with-ed25519", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill implementing-digital-signatures-with-ed25519 -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install mukul975/Anthropic-Cybersecurity-Skills implementing-digital-signatures-with-ed25519 --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/mukul975/Anthropic-Cybersecurity-Skills.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/implementing-digital-signatures-with-ed25519 .opencode/skills/implementing-digital-signatures-with-ed25519 && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "implementing-digital-signatures-with-ed25519" agent skill from https://github.com/mukul975/Anthropic-Cybersecurity-Skills/tree/main/skills/implementing-digital-signatures-with-ed25519 into .opencode/skills/implementing-digital-signatures-with-ed25519/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "implementing-digital-signatures-with-ed25519", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
implementing-digital-signatures-with-ed25519- GitHub stars
- 34k
- Token cost
- ~875 tokens
- SKILL.md length
- 356 words
- Files
- 8 (incl. scripts, references, assets)
- Skills in repo
- 644
- Repo updated
- First seen
- Licence
- Apache-2.0
At a glance
Implements digital signatures using the Ed25519 algorithm (Curve25519), covering key-pair generation, signing, signature verification, and security tradeoffs versus RSA and ECDSA.
- Artifact signing and authentication-integrity checks to a system
- SKILL.md covers Overview, When to Use, Prerequisites and Objectives, plus 3 more sections
- Runs Python scripts from its folder
- Advising on Ed25519 key properties and validation criteria
What it does
Implementing Digital Signatures With Ed25519 is an agent skill from mukul975/Anthropic-Cybersecurity-Skills. Implements digital signatures using the Ed25519 algorithm (Curve25519), covering key-pair generation, signing, signature verification, and security tradeoffs versus RSA and ECDSA. Use when adding message or artifact signing and authentication-integrity checks to a system, or when advising on Ed25519 key properties and validation criteria.
Its SKILL.md is about 880 tokens, which your agent loads only when the skill is triggered. The skill folder holds 10 other files, including scripts, reference files and assets (for example `assets/template.md`, `references/api-reference.md` and `references/standards.md`).
It sits in Security, covering Cryptography and Webhooks. The repository describes itself as: 817 structured cybersecurity skills for AI agents · Mapped to 6 frameworks: MITRE ATT&CK, NIST CSF 2.0, MITRE ATLAS, D3FEND, NIST AI RMF & MITRE F3 (Fight Fraud) · agentskills.io…. The licence is Apache-2.0.
When your agent uses it
- Artifact signing and authentication-integrity checks to a system
- Advising on Ed25519 key properties and validation criteria
Example prompts
- “Use the implementing-digital-signatures-with-ed25519 skill to implement digital signatures using the Ed25519 algorithm (Curve25519), covering…”
- “/implementing-digital-signatures-with-ed25519”
Requirements
- Python 3
What it can do on your machine
Read from SKILL.md and the folder at commit 54a7988. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
Ships 2 files in scripts/ (Python), which the agent can run.
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Implementing Digital Signatures With Ed25519 loads about 875 tokens when it runs, and up to ~2k if it reads all its reference files. Until then it costs about 96 tokens; SKILL.md has 356 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); the scripts in this folder are not scanned.
SKILL.md
The full file from mukul975/Anthropic-Cybersecurity-Skills at commit 54a7988, republished under its Apache-2.0 licence (© mukul975). 356 words, ~875 tokens.
Download SKILL.mdSave it as
.claude/skills/implementing-digital-signatures-with-ed25519/SKILL.md (or your agent's skills folder). This skill also uses 7 other files; get the full folder from GitHub.- name
- implementing-digital-signatures-with-ed25519
- description
- Implements digital signatures using the Ed25519 algorithm (Curve25519), covering key-pair generation, signing, signature verification, and security tradeoffs versus RSA and ECDSA. Use when adding message or artifact signing and authentication-integrity checks to a system, or when advising on Ed25519 key properties and validation criteria.
- domain
- cybersecurity
- subdomain
- cryptography
- tags
- cryptography, digital-signatures, ed25519, authentication, integrity
- version
- 1.0
- author
- mahipal
- license
- Apache-2.0
- nist_csf
- PR.DS-01, PR.DS-02, PR.DS-10
- mitre_attack
- T1600, T1573, T1553
Implementing Digital Signatures with Ed25519
Overview
Ed25519 is a high-performance digital signature algorithm using the Edwards curve Curve25519. It provides 128-bit security with 64-byte signatures and 32-byte keys, offering significant advantages over RSA and ECDSA including deterministic signatures (no random nonce needed), resistance to side-channel attacks, and fast verification. This skill covers implementing Ed25519 for document signing, code signing, and API authentication.
When to Use
- When deploying or configuring implementing digital signatures with ed25519 capabilities in your environment
- When establishing security controls aligned to compliance requirements
- When building or improving security architecture for this domain
- When conducting security assessments that require this implementation
Prerequisites
- Familiarity with cryptography concepts and tools
- Access to a test or lab environment for safe execution
- Python 3.8+ with required dependencies installed
- Appropriate authorization for any testing activities
Objectives
- Generate Ed25519 key pairs for signing
- Sign messages and files with Ed25519
- Verify signatures against public keys
- Implement multi-signature verification
- Build a simple code signing system
- Compare Ed25519 performance with RSA and ECDSA
Key Concepts
Ed25519 vs RSA vs ECDSA
| Property | Ed25519 | RSA-3072 | ECDSA P-256 |
|---|---|---|---|
| Security | 128-bit | 128-bit | 128-bit |
| Public key size | 32 bytes | 384 bytes | 64 bytes |
| Signature size | 64 bytes | 384 bytes | 64 bytes |
| Key generation | ~50 us | ~100 ms | ~1 ms |
| Sign | ~70 us | ~5 ms | ~200 us |
| Verify | ~200 us | ~200 us | ~500 us |
| Deterministic | Yes | No (PSS) | No (unless RFC 6979) |
Show full SKILL.md (127 more words)Show less
Key Properties
- Deterministic: Same message + key always produces same signature
- Collision-resistant: No separate hash function needed
- Side-channel resistant: Constant-time implementation
- Small keys: 32 bytes each (public and private)
Security Considerations
- Ed25519 does not support key recovery from signatures
- Verify the full message, not a hash (Ed25519 hashes internally)
- Public keys must be validated before use (check for low-order points)
- Private keys should be stored encrypted at rest
- Ed25519 is not yet approved for all NIST use cases (Ed448 is preferred for federal)
Validation Criteria
- Key pair generation produces valid Ed25519 keys
- Signature verification succeeds for valid message
- Signature verification fails for tampered message
- Signature verification fails for wrong public key
- Deterministic: same input produces same signature
- File signing and verification works correctly
- Performance meets or exceeds RSA-3072
© mukul975, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
SKILL.md and 7 other files (scripts, references, assets) in skills/implementing-digital-signatures-with-ed25519 of mukul975/Anthropic-Cybersecurity-Skills.
- SKILL.md
- LICENSE
- assets/template.md
- references/api-reference.md
- references/standards.md
- references/workflows.md
- scripts/agent.py
- scripts/process.py
Open the folder on GitHubat commit 54a7988
Compare with similar skills
Implementing Digital Signatures With Ed25519 next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Implementing Digital Signatures With Ed25519 this skillmukul975/Anthropic-Cybersecurity-Skills | 34k | — | ~875 | Automated safety check: Pass | Apache-2.0 | |
| Crypto Auditbriiirussell/cybersecurity-skills | 413 | — | ~2.8k | Automated safety check: Notes | MIT | |
| Stripe Best Practiceskanchengw/cnllm | 173 | 2 repos | ~925 | Automated safety check: Pass | Apache-2.0 | |
| Stripe Best Practicesfossasia/eventyay | 1.7k | 1 repos | ~1.7k | Automated safety check: Pass | Apache-2.0 | |
| Bom Explorecdxgen/cdxgen | 1.1k | — | ~1.2k | Automated safety check: Pass | Apache-2.0 | |
| Crypto Analysishypnguyen1209/offensive-claude | 388 | — | ~2.2k | Automated safety check: Pass | MIT |
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Related
Categories
Questions about Implementing Digital Signatures With Ed25519
What does Implementing Digital Signatures With Ed25519 do?
Implements digital signatures using the Ed25519 algorithm (Curve25519), covering key-pair generation, signing, signature verification, and security tradeoffs versus RSA and ECDSA. Implementing Digital Signatures With Ed25519 is an agent skill from mukul975/Anthropic-Cybersecurity-Skills. Implements digital signatures using the Ed25519 algorithm (Curve25519), covering key-pair generation, signing, signature verification, and security tradeoffs versus RSA and ECDSA.
When should I use Implementing Digital Signatures With Ed25519?
Implementing Digital Signatures With Ed25519 fits situations like: artifact signing and authentication-integrity checks to a system; advising on Ed25519 key properties and validation criteria.
How do I install Implementing Digital Signatures With Ed25519 in Claude Code?
Run `npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill implementing-digital-signatures-with-ed25519 -a claude-code`. Or copy the skill folder (skills/implementing-digital-signatures-with-ed25519 in mukul975/Anthropic-Cybersecurity-Skills) into .claude/skills/implementing-digital-signatures-with-ed25519 in your project. Claude Code loads it when a task matches its description.
How do I install Implementing Digital Signatures With Ed25519 in Codex?
Run `npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill implementing-digital-signatures-with-ed25519 -a codex`. Or copy the skill folder (skills/implementing-digital-signatures-with-ed25519 in mukul975/Anthropic-Cybersecurity-Skills) into .agents/skills/implementing-digital-signatures-with-ed25519 in your project. Codex loads it when a task matches its description.
Can I use Implementing Digital Signatures With Ed25519 in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill implementing-digital-signatures-with-ed25519 -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/implementing-digital-signatures-with-ed25519, .gemini/skills/implementing-digital-signatures-with-ed25519, .github/skills/implementing-digital-signatures-with-ed25519 and .opencode/skills/implementing-digital-signatures-with-ed25519 in your project.
What does Implementing Digital Signatures With Ed25519 need to run?
Going by SKILL.md and its folder, Implementing Digital Signatures With Ed25519 needs Python for the scripts in its folder. Our summary lists: Python 3.
Does Implementing Digital Signatures With Ed25519 access the network?
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Is Implementing Digital Signatures With Ed25519 safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. The check reads SKILL.md only: the scripts in the folder are not scanned, so read them before running anything.
What licence does Implementing Digital Signatures With Ed25519 use?
Implementing Digital Signatures With Ed25519 is published under the Apache-2.0 licence (declared in SKILL.md). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does Implementing Digital Signatures With Ed25519 use?
About 875 tokens (SKILL.md is roughly 3.5k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 1.1k tokens, read only when the agent opens those files.
What are the alternatives to Implementing Digital Signatures With Ed25519?
Skills that share tags, products or a category with Implementing Digital Signatures With Ed25519: Crypto Audit (briiirussell/cybersecurity-skills, 413 stars), Stripe Best Practices (kanchengw/cnllm, 173 stars), Stripe Best Practices (fossasia/eventyay, 1.7k stars) and Bom Explore (cdxgen/cdxgen, 1.1k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Implementing Digital Signatures With Ed25519?
mukul975 (a GitHub user) maintains it in mukul975/Anthropic-Cybersecurity-Skills, which has 34,116 GitHub stars. The repository holds 644 skills in this directory. The repository was last updated on August 31, 2026.
Source: mukul975/Anthropic-Cybersecurity-Skills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.