Cert Tool

Name: Cert Tool
Author: mkontani

A comprehensive tool for certificates: Key Pair Generation, CSR Generation, Public Key Derivation, and Inspection.

As of June 2026, Cert Tool has 32 users in the Developer Tools category.

mkontani Developer Tools

Chrome Web Store ↗.crx

Users+52.4%

Rating0%

—

— reviews

Reviews0%

—

Version

1.0.1

Manifest V3

History

6 snapshots

Tracking since Apr 7, 2026.

View as table

Date	Users	Rating	Reviews	Version
Apr 7, 2026	21	—	—	1.0.1
Apr 21, 2026	20	—	—	1.0.1
May 2, 2026	21	—	—	1.0.1
May 10, 2026	22	—	—	1.0.1
May 18, 2026	30	—	—	1.0.1
May 27, 2026	29	—	—	1.0.1
Now	32	—	—	1.0.1

Permissions & access

Permissions: downloads
Host access: None declared

Screenshots

About

A powerful and elegant Chrome extension for handling X.509 certificates and cryptographic keys.

**Features**
1. Key Pair Generation
Generate cryptographic key pairs instantly using the Web Crypto API.
- Algorithms: RSA (2048, 4096 bits), ECDSA (P-256, P-384, P-521), and Ed25519.
- Standard Formats: Private keys are exported in PKCS#8 and public keys in SPKI.
- Save As: Easily download keys with a standard OS save dialog.

2. CSR Generation
Create Certificate Signing Requests (CSR) with a user-friendly form.
- Customizable DN: Set Common Name, Organization, Country, and more.
- SAN Support: Add multiple Subject Alternative Names (DNS, IP, Email, URI).
- Flexible Signing: Sign the request using your own private key.

3. Public Key Derivation
Extract the public key component from various sources.
- Input Types: Supports Private Keys (PKCS#8/PKCS#1), Certificates, or CSRs.
- Auto-Detection: Automatically identifies the input type and algorithm.

4. Certificate/CSR Inspector
View detailed information about certificates and signing requests.
- Comprehensive View: Shows Serial Number, Subject, Issuer, Validity, and Public Key details.
- Extension Decoding: Human-readable decoding for SANs, Basic Constraints, Key Usage, and Extended Key Usage (EKU).