"Let's Encrypt" matching MCP servers:

Slim OPNsense MCP Server — 62 tools for managing firewall infrastructure via the OPNsense REST API. Covers DNS/Unbound, Firewall rules, Diagnostics, Interfaces, DHCP (ISC + Kea), System/Backups, ACME/Let's Encrypt, and Firmware. No SSH, no shell, API-only with 3 runtime dependencies. AGPL-3.0 + Commercial dual-licensed.

Free SSL/TLS scanning and Let's Encrypt certificate issuance (private key stays local), plus certificate-expiry monitoring via one MCP server. Public scan and cert tools need no account.

A standalone MCP server for managing SSL/TLS certificates across FortiGate, Windows, Linux, and Fortinet devices using Let's Encrypt with Cloudflare DNS-01 challenges.

Secrets vault for Claude Code. Encrypt API keys, tokens and passwords with AES-256. Full audit logs, MCP access rules, and zero-knowledge mode. Secrets never appear in chat.

Enables AI agents to scan and audit environment files for leaked secrets, sanitize them, encrypt/decrypt vaults, and run processes with zero-disk secret injection.

Enables ChatGPT and Codex to request public keys, prepare and sign exact Nostr events, encrypt or decrypt NIP-04/NIP-44 payloads, and publish with per-relay acknowledgement, while the private key stays in the user's Alby, nos2x, or remote NIP-46 signer. Every operation is queued for local browser approval, with one-use signing intents and verification before anything is broadcast.

Enables users to encrypt and decrypt data, generate keypairs, and list supported algorithms through MCP, with decryption keys supplied via environment variables or files rather than the model.

Enables timelock encryption using the Shutter Network, allowing users to encrypt messages that can only be decrypted after a specified future time. Supports natural language time parsing and provides trustless time-delayed communications.

Enables agents to encrypt and sanitize sensitive data such as credentials, credit card numbers, and addresses locally before dispatching prompts to cloud LLMs, then rehydrate the masked values client-side. It runs deterministically with zero external dependencies over MCP JSON-RPC stdio, so no plaintext PII leaves the user's machine.

Enables AI assistants to encrypt and decrypt files or text using the SAFE utility with support for passwords, public keys, and GitHub usernames. It provides tools for key generation, identity listing, and inspecting encrypted file metadata.

Integrates AI safety analysis, red-teaming, and prompt auditing directly into MCP-compatible clients like Claude Desktop and Cursor IDE, allowing real-time analysis of prompts and detection of jailbreak attempts.

Enables encrypting and decrypting plain-text messages with AES-256-CBC using any passphrase, with automatic scrypt key derivation and a fresh random IV per call. It also exposes a resource describing the algorithm and ready-to-use prompts, and can be run directly inside VS Code Copilot Chat or the MCP Inspector.

A proxy server that sits between MCP clients and servers, providing authentication, tool discovery, caching, and guardrail enforcement to protect MCP servers from malicious inputs.