Fortify Development
coollabsio/coolify
ACTIVATE when the user works on authentication in Laravel. An agent skill from coollabsio/coolify.
Agent skill
Implementing JWT Signing And Verification
Implements secure JWT (RFC 7519) signing and verification using HMAC-SHA256, RSA-PSS, ES256, and EdDSA, including token expiration, claims validation, and defenses against algorithm-confusion…
Install Implementing JWT Signing And Verification
$ npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill implementing-jwt-signing-and-verification -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install mukul975/Anthropic-Cybersecurity-Skills implementing-jwt-signing-and-verification --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-jwt-signing-and-verification .claude/skills/implementing-jwt-signing-and-verification && 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-jwt-signing-and-verification" agent skill from https://github.com/mukul975/Anthropic-Cybersecurity-Skills/tree/main/skills/implementing-jwt-signing-and-verification into .claude/skills/implementing-jwt-signing-and-verification/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "implementing-jwt-signing-and-verification", 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-jwt-signing-and-verificationType 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-jwt-signing-and-verification -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install mukul975/Anthropic-Cybersecurity-Skills implementing-jwt-signing-and-verification --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-jwt-signing-and-verification .agents/skills/implementing-jwt-signing-and-verification && 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-jwt-signing-and-verification" agent skill from https://github.com/mukul975/Anthropic-Cybersecurity-Skills/tree/main/skills/implementing-jwt-signing-and-verification into .agents/skills/implementing-jwt-signing-and-verification/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "implementing-jwt-signing-and-verification", 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-jwt-signing-and-verification -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install mukul975/Anthropic-Cybersecurity-Skills implementing-jwt-signing-and-verification --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-jwt-signing-and-verification .cursor/skills/implementing-jwt-signing-and-verification && 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-jwt-signing-and-verification" agent skill from https://github.com/mukul975/Anthropic-Cybersecurity-Skills/tree/main/skills/implementing-jwt-signing-and-verification into .cursor/skills/implementing-jwt-signing-and-verification/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "implementing-jwt-signing-and-verification", 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-jwt-signing-and-verification--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-jwt-signing-and-verification -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install mukul975/Anthropic-Cybersecurity-Skills implementing-jwt-signing-and-verification --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-jwt-signing-and-verification .gemini/skills/implementing-jwt-signing-and-verification && 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-jwt-signing-and-verification" agent skill from https://github.com/mukul975/Anthropic-Cybersecurity-Skills/tree/main/skills/implementing-jwt-signing-and-verification into .gemini/skills/implementing-jwt-signing-and-verification/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "implementing-jwt-signing-and-verification", 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-jwt-signing-and-verificationInstalls 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-jwt-signing-and-verification -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-jwt-signing-and-verification .github/skills/implementing-jwt-signing-and-verification && 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-jwt-signing-and-verification" agent skill from https://github.com/mukul975/Anthropic-Cybersecurity-Skills/tree/main/skills/implementing-jwt-signing-and-verification into .github/skills/implementing-jwt-signing-and-verification/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "implementing-jwt-signing-and-verification", 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-jwt-signing-and-verification -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-jwt-signing-and-verification --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-jwt-signing-and-verification .opencode/skills/implementing-jwt-signing-and-verification && 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-jwt-signing-and-verification" agent skill from https://github.com/mukul975/Anthropic-Cybersecurity-Skills/tree/main/skills/implementing-jwt-signing-and-verification into .opencode/skills/implementing-jwt-signing-and-verification/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "implementing-jwt-signing-and-verification", 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-jwt-signing-and-verification- GitHub stars
- 34k
- Token cost
- ~864 tokens
- SKILL.md length
- 333 words
- Files
- 8 (incl. scripts, references, assets)
- Skills in repo
- 644
- Repo updated
- First seen
- Licence
- Apache-2.0
At a glance
Implements secure JWT (RFC 7519) signing and verification using HMAC-SHA256, RSA-PSS, ES256, and EdDSA, including token expiration, claims validation, and defenses against algorithm-confusion…
- Hardening JWT-based authentication/authorization
- SKILL.md covers Overview, When to Use, Prerequisites and Objectives, plus 3 more sections
- Runs Python scripts from its folder
- Auditing token verification code for common JWT vulnerabilities
What it does
Implementing JWT Signing And Verification is an agent skill from mukul975/Anthropic-Cybersecurity-Skills. Implements secure JWT (RFC 7519) signing and verification using HMAC-SHA256, RSA-PSS, ES256, and EdDSA, including token expiration, claims validation, and defenses against algorithm-confusion, none-algorithm, and key-injection attacks. Use when adding or hardening JWT-based authentication/authorization, or when auditing token verification code for common JWT vulnerabilities.
Its SKILL.md is about 860 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 Backend & APIs, covering Authentication. 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
- Hardening JWT-based authentication/authorization
- Auditing token verification code for common JWT vulnerabilities
Example prompts
- “Use the implementing-jwt-signing-and-verification skill to implement secure JWT (RFC 7519) signing and verification using HMAC-SHA256, RSA-PSS…”
- “/implementing-jwt-signing-and-verification”
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 JWT Signing And Verification loads about 864 tokens when it runs, and up to ~1.9k if it reads all its reference files. Until then it costs about 105 tokens; SKILL.md has 333 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). 333 words, ~864 tokens.
Download SKILL.mdSave it as
.claude/skills/implementing-jwt-signing-and-verification/SKILL.md (or your agent's skills folder). This skill also uses 7 other files; get the full folder from GitHub.- name
- implementing-jwt-signing-and-verification
- description
- Implements secure JWT (RFC 7519) signing and verification using HMAC-SHA256, RSA-PSS, ES256, and EdDSA, including token expiration, claims validation, and defenses against algorithm-confusion, none-algorithm, and key-injection attacks. Use when adding or hardening JWT-based authentication/authorization, or when auditing token verification code for common JWT vulnerabilities.
- domain
- cybersecurity
- subdomain
- cryptography
- tags
- cryptography, jwt, authentication, token-security, digital-signatures
- 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 JWT Signing and Verification
Overview
JSON Web Tokens (JWT) defined in RFC 7519 are compact, URL-safe tokens used for authentication and authorization in web applications. This skill covers implementing secure JWT signing with HMAC-SHA256, RSA-PSS, and EdDSA algorithms, along with verification, token expiration, claims validation, and defense against common JWT attacks (algorithm confusion, none algorithm, key injection).
When to Use
- When deploying or configuring implementing jwt signing and verification 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
- Implement JWT signing with HS256, RS256, ES256, and EdDSA
- Verify JWT signatures and validate standard claims
- Implement token expiration, not-before, and audience validation
- Defend against algorithm confusion and none algorithm attacks
- Implement JWT key rotation with JWK Sets
- Build a complete authentication middleware
Key Concepts
JWT Algorithms
| Algorithm | Type | Key | Security Level |
|---|---|---|---|
| HS256 | Symmetric (HMAC) | Shared secret | 128-bit |
| RS256 | Asymmetric (RSA) | RSA key pair | 112-bit |
| ES256 | Asymmetric (ECDSA) | P-256 key pair | 128-bit |
| EdDSA | Asymmetric (Ed25519) | Ed25519 pair | 128-bit |
Common JWT Attacks
- Algorithm confusion: Switching from RS256 to HS256, using public key as HMAC secret
- None algorithm: Setting alg=none to bypass signature verification
- Key injection: Embedding key in JWK header
- Weak secrets: Brute-forcing short HMAC secrets
- Token replay: Reusing valid tokens without expiration
Security Considerations
- Always validate the algorithm header against an allowlist
- Never accept alg=none in production
- Use asymmetric algorithms (RS256, ES256) for distributed systems
- Set short expiration times (15 min for access tokens)
- Implement token refresh mechanism
- Store secrets securely (not in source code)
Validation Criteria
- JWT signing produces valid tokens for all algorithms
- Signature verification rejects tampered tokens
- Expired tokens are rejected
- Algorithm confusion attack is prevented
- None algorithm is rejected
- JWK key rotation works correctly
- Claims validation enforces all required claims
© 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-jwt-signing-and-verification 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 JWT Signing And Verification 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 JWT Signing And Verification this skillmukul975/Anthropic-Cybersecurity-Skills | 34k | — | ~864 | Automated safety check: Pass | Apache-2.0 | |
| Fortify Developmentcoollabsio/coolify | 63k | 4 repos | ~1.9k | Automated safety check: Pass | MIT | |
| Supabase Development and Debuggingsupabase/agent-skills | 2.7k | 3 repos | ~3.6k | Automated safety check: Pass | MIT | |
| Better Auth Best Practiceslatitude-dev/latitude-llm | 4.7k | 7 repos | ~1.6k | Automated safety check: Pass | MIT | |
| Gitnexus Exploringaws-samples/sample-kolya-br-proxy | 106 | 12 repos | ~749 | Automated safety check: Pass | MIT-0 | |
| Supabasecurvenote/curvenote | 170 | 5 repos | ~2.2k | Automated safety check: Pass | Custom licence |
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Related
Categories
Questions about Implementing JWT Signing And Verification
What does Implementing JWT Signing And Verification do?
Implements secure JWT (RFC 7519) signing and verification using HMAC-SHA256, RSA-PSS, ES256, and EdDSA, including token expiration, claims validation, and defenses against algorithm-confusion…. Implementing JWT Signing And Verification is an agent skill from mukul975/Anthropic-Cybersecurity-Skills. Implements secure JWT (RFC 7519) signing and verification using HMAC-SHA256, RSA-PSS, ES256, and EdDSA, including token expiration, claims validation, and defenses against algorithm-confusion, none-algorithm, and key-injection attacks.
When should I use Implementing JWT Signing And Verification?
Implementing JWT Signing And Verification fits situations like: hardening JWT-based authentication/authorization; auditing token verification code for common JWT vulnerabilities.
How do I install Implementing JWT Signing And Verification in Claude Code?
Run `npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill implementing-jwt-signing-and-verification -a claude-code`. Or copy the skill folder (skills/implementing-jwt-signing-and-verification in mukul975/Anthropic-Cybersecurity-Skills) into .claude/skills/implementing-jwt-signing-and-verification in your project. Claude Code loads it when a task matches its description.
How do I install Implementing JWT Signing And Verification in Codex?
Run `npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill implementing-jwt-signing-and-verification -a codex`. Or copy the skill folder (skills/implementing-jwt-signing-and-verification in mukul975/Anthropic-Cybersecurity-Skills) into .agents/skills/implementing-jwt-signing-and-verification in your project. Codex loads it when a task matches its description.
Can I use Implementing JWT Signing And Verification 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-jwt-signing-and-verification -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-jwt-signing-and-verification, .gemini/skills/implementing-jwt-signing-and-verification, .github/skills/implementing-jwt-signing-and-verification and .opencode/skills/implementing-jwt-signing-and-verification in your project.
What does Implementing JWT Signing And Verification need to run?
Going by SKILL.md and its folder, Implementing JWT Signing And Verification needs Python for the scripts in its folder. Our summary lists: Python 3.
Does Implementing JWT Signing And Verification 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 JWT Signing And Verification 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 JWT Signing And Verification use?
Implementing JWT Signing And Verification 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 JWT Signing And Verification use?
About 864 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 1k tokens, read only when the agent opens those files.
What are the alternatives to Implementing JWT Signing And Verification?
Skills that share tags, products or a category with Implementing JWT Signing And Verification: Fortify Development (coollabsio/coolify, 63k stars), Supabase Development and Debugging (supabase/agent-skills, 2.7k stars), Better Auth Best Practices (latitude-dev/latitude-llm, 4.7k stars) and Gitnexus Exploring (aws-samples/sample-kolya-br-proxy, 106 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Implementing JWT Signing And Verification?
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.