Verifying Key Pair

Extracting modulus hash and performing match comparison...

Online SSL Certificate & Private Key Matcher

Encountering x509: certificate signed by unknown authority or key mismatch errors during Nginx, Apache, or CDN deployment? Simply paste your certificate (CRT/PEM) and private key (KEY), and this tool will instantly extract and compare their cryptographic modulus hashes.

πŸ›‘οΈ Zero-Risk Commitment: All match computations are performed locally within your browser's JavaScript sandbox. Your private keys are never transmitted to any server!

Certificate Modulus MD5: -

Private Key Modulus MD5: -

Match Result: -

πŸ“‹ Certificate & Key Matcher: Examples & Core Principles

The core principle of SSL verification relies on extracting and comparing the public key modulus from the digital certificate with the private key modulus. Mathematically, a matching pair must have identical moduli. To simplify the comparison, this tool computes an MD5 hash of these lengthy strings. See the real-world match examples below:

🟒 Match Successful Algorithm: RSA (2048 bit)

[Certificate] Modulus MD5: a1b2c3d4e5f67890abcdef1234567890

[Private Key] Modulus MD5: a1b2c3d4e5f67890abcdef1234567890

Conclusion: Both hashes are identical (100% Match). This indicates that the certificate and private key files are perfectly paired. You can safely deploy them to your Web server without triggering any key-related startup errors.
πŸ”΄ Match Failed Scenario: Accidendally mixing up KEY files of multiple domains

[Certificate] Modulus MD5: 99999994e5f67890abcdef1234567890

[Private Key] Modulus MD5: 88888884e5f67890abcdef9999999999

Conclusion: Hashes mismatch. Forcing these files into your Nginx configuration will trigger a critical failure during startup, such as nginx: [emerg] SSL_CTX_use_PrivateKey_file(...) failed. Please re-verify the original private key generated during your certificate application.

Frequently Asked Questions About TLS/SSL Certificate Verification

1. Why do I need to verify the TLS/SSL certificate and private key match before deployment?

During deployment on production servers (such as Nginx, Apache, or IIS), any mismatch between the certificate file (.crt/.pem) and the private key file (.key) will cause the server to fail to start or throw critical errors (such as Nginx's "X509_check_private_key failed"). Conducting a pre-verification via this tool before going live effectively eliminates the risk of site downtime caused by invalid or mismatched certificates.

2. How is the key pair match verified?

  • Public Key Modulus Consistency: By calculating and comparing the MD5/SHA256 hash values of both the certificate's public key and the private key, the tool determines whether they were generated from the exact same cryptographic key pair.

3. Is it safe to paste my private key into this website?

Privacy & Security Guarantee: We strictly adherence to a zero-storage, zero-logging policy. Your private keys and certificate assets are processed solely in temporary memory and are completely and permanently destroyed as soon as the session ends.