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DevToolKit

Digital Signature Validator

Verify digital signatures, inspect X.509 certificates, and explore ASN.1 structures. Supports PKCS#7, CMS, and trust chain validation. 100% client-side and secure.

Upload Certificate/Signature

Upload .crt, .pem, .p7s, or .sig files

Processed locally
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How to Use

The Digital Signature Validator is a high-security utility designed to inspect X.509 certificates and CMS/PKCS#7 signature containers. It provides a human-readable audit of the technical details and structural integrity of cryptographic files.

How to use this tool

  1. Upload File: Drag and drop a .crt, .pem, .sig, or .p7s file into the dropzone, or paste the PEM-encoded text directly.
  2. Technical Details: Review the "Technical Details" tab to see subject/issuer information, validity periods, public key algorithms, and certificate extensions.
  3. ASN.1 Exploration: Switch to the "ASN.1 Structure" tab to explore the raw binary data structure in a recursive tree format.
  4. Verify Chain: For CMS objects, the tool will list all included certificates and their individual validity status.

About This Tool

Industrial-Grade Cryptographic Inspection

Digital signatures and certificates are the backbone of modern internet security. This tool is designed for developers, system administrators, and security auditors who need to verify the authenticity and correctness of cryptographic objects without relying on complex CLI commands.

By providing a visual **ASN.1 Tree**, we make it easy to debug encoding issues or verify that custom OIDs and extensions are correctly implemented in your certificates.

Why Use This Tool

100% Client-Side Security

Privacy is non-negotiable when dealing with security credentials. Unlike other online validators, our tool performs all cryptographic parsing and analysis locally in your browser. Your certificates, private keys (if present in files), and signatures are never sent to a server. Your security profile remains completely private.

FAQ

What signature formats are supported?
This tool supports PKCS#7/CMS detached and attached signatures, X.509 certificate inspection (PEM and DER), and ASN.1 structure browsing. It validates signature integrity and certificate chain trust.
How does certificate chain validation work?
The validator checks each certificate in the chain from leaf to root, verifying that each issuer signed the next certificate and that none are expired or revoked. A valid chain means the signature can be trusted back to a known Certificate Authority.
Is my certificate data kept private?
Yes. All signature verification and certificate parsing happens locally in your browser using Web Crypto APIs. No certificates, private keys, or signed data are transmitted to any server.