# X.509 Certificate Inspector & Exporter

> Private X.509 Certificate Inspector & Parser | Privatools
> Canonical URL: [https://privatools.dev/tools/cert-inspector/](https://privatools.dev/tools/cert-inspector/)
> Markdown Alternate: [https://privatools.dev/tools/cert-inspector.md](https://privatools.dev/tools/cert-inspector.md)
> Execution Architecture: 100% Client-Side In-Memory Execution (Zero Remote Egress)

## Overview
Inspect, parse, and validate X.509 SSL/TLS certificates and CSRs entirely inside your browser. Analyze validity periods, SANs, key sizes, digital signatures, and extension constraints without sharing sensitive cryptographic material.

## Format Specifications
- **Category:** Security & Dev
- **Supported Formats:** `PEM`, `DER`, `CRT`, `CER`, `Public Key`, `JSON`
- **Privacy Guarantee:** 0 bytes uploaded to remote servers. All computation executes locally in browser memory.
- **Compliance:** GDPR, HIPAA & SOC 2 Friendly (process sensitive payloads and PII directly on your local device).

## Technology Stack
- PKI.js ASN.1 Parser
- Web Crypto API
- X.509 ASN.1 Schema Validator
- Fingerprint Hasher

## How It Works
1. PEM or DER encoded certificates are decoded into raw binary ASN.1 structures locally.
2. The parser extracts Subject, Issuer, Serial Number, Validity Ranges, Subject Alternative Names (SANs), and Key Usages.
3. Web Crypto computes SHA-256 and SHA-1 fingerprints in memory for cryptographic verification.
4. Validity timelines and expiration warnings calculate based on current system time.

## Practical Use Cases
### DevOps & SRE Certificate Verification
Verify newly issued TLS certificates before deployment to production ingress controllers, load balancers, or CDN endpoints.

### Subject Alternative Name (SAN) Auditing
Ensure multi-domain and wildcard SSL certificates include all required production and staging hostnames.

### Enterprise PKI & Internal CA Troubleshooting
Diagnose certificate chain issues, basic constraints, and key usage extensions in corporate intranet environments.

### Security & Expiration Audits
Quickly inspect expiration dates and signature algorithms to replace legacy SHA-1 certificates with modern SHA-256/ECC certs.

## Frequently Asked Questions
### Does this tool upload my certificate or public key to any server?
No. ASN.1 decoding and fingerprint calculations happen strictly inside your browser via Web Crypto and pure client-side JavaScript.

### Can this tool read private keys?
This tool is designed specifically for public X.509 certificates (.crt, .pem, .cer) and Certificate Signing Requests (CSRs). It does not require or accept private keys.

### Does it support both RSA and Elliptic Curve (ECDSA) certificates?
Yes. It parses RSA certificates (2048, 4096-bit, etc.) and modern ECDSA certificates with NIST curves (P-256, P-384, P-521).

## Related Tools
- [JWT & OAuth Token Debugger](https://privatools.dev/tools/jwt-inspector/)
- [Cryptographic Checksum & File Hash Studio](https://privatools.dev/tools/hash-studio/)
- [Network & Subnet CIDR Studio](https://privatools.dev/tools/subnet-calculator/)

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