SSL Certificate & Key Matcher
SSL Certificate & Key Matcher: Extracts public key modulus from certificate and compares against public modulus of private key.
About this ssl certificate & key matcher
SSL Certificate & Key Matcher — browser-based utility.
How this tool works
Implements client-side SSL Certificate & Key Matcher operations. Extracts public key modulus from certificate and compares against public modulus of private key specifically designed for a systems engineer verifies whether an ssl certificate matches a private key before deploying to production.
- PEM Armor Stripping & DER Decoding: Strips '-----BEGIN CERTIFICATE-----' headers and decodes Base64 to raw ASN.1 DER binary bytes.
- ASN.1 Structure Traversal: Parses the TBSCertificate sequence, extracting serial numbers, signature algorithms, and X.500 distinguished names.
- Extension Extraction: Decodes X.509v3 extensions, extracting SAN DNS names, basic constraints (CA flag), and key usage flags.
- Diagnostic Reporting: Computes SHA-256 fingerprint, checks expiration status against the current date, and warns if certificates are expired or self-signed.
Worked example
Scenario: Exercise the required-pair boundary before comparing certificate and public-key SPKI bytes.
Sample input:
Processing: Rejects missing certificate or publicKey PEM fields before X.509 parsing or SHA-256 comparison.
Illustrative output:
Limits and verification
Rejects corrupted PEM files with invalid Base64 characters or missing encapsulation boundaries. Warns users when inspecting self-signed root certificates or certificates with weak 1024-bit RSA keys.
Examples demonstrate an expected workflow; they do not prove every input or every branch of an external specification. Check important results with an independent source before using them for money, security, compliance, safety, or irreversible file changes.
Browser processing boundary
Tool input is processed by code running in the browser and is not intentionally sent to a CZOA processing API. The page can still request ordinary site assets, analytics, or advertising when those services are enabled. Browser extensions and managed-device software remain outside this tool's control.
Relevant references
These references govern or help explain the format, protocol, or calculation used here. Listing a reference does not claim certification or complete implementation of every optional feature.
Content owner: CZOA Tools · Last reviewed: 2026-09-15 · Review methodology
How to use it
- Enter, paste, or select your input data into the SSL Certificate & Key Matcher workspace controls.
- Review available parameter fields, units, formats, or options configured for your task.
- Click the action button or observe immediate live calculations rendered in your browser runtime.
- Inspect the resulting output and any diagnostic messages, then copy or download the result if needed.
Frequently asked questions
Which JSON fields are required by SSL Certificate & Key Matcher?+
It requires certificate and publicKey PEM strings. Missing either field returns a structured match false result with the explicit required-fields error.
How does it compare a certificate and public key?+
It reads the certificate with X509Certificate, hashes its raw SubjectPublicKeyInfo bytes with SHA-256, base64-decodes the supplied PEM public key, and compares those digests.
What did the browser fixture verify?+
An empty JSON object returned match false and the error Provide JSON with certificate and publicKey PEM values. That verifies the required-input boundary only.
Does a matching result validate certificate trust?+
No. A match only means the two supplied SPKI byte digests are equal. It does not validate issuer trust, hostname, expiry, revocation, or key usage.