📖 Description
1. Why is Matching Verification Necessary?
In complex operational environments, managing multiple domains and multiple sets of certificates can easily lead to confusion:
- Prevent Service Startup Failures: If the certificate and private key do not match, Nginx or Apache will report errors (such as
SSL_CTX_use_PrivateKey_file failed) when loading the configuration, causing the website to become inaccessible.
- Save Troubleshooting Time: Searching for errors in configuration files that can span thousands of lines is painful. A one-click verification before deployment can eliminate 90% of configuration risks.
- Confirm Backup Integrity: Check if the certificate bundle migrated from an old server is complete, ensuring the private key still corresponds to the existing certificate.
- CSR Verification: Verify that a newly issued certificate matches the private key you used when initially generating the CSR (Certificate Signing Request).
2. Core Functionality Analysis
This site's tool provides non-invasive, precise verification through underlying algorithm comparison:
A. Modulus Consistency Check
- Principle Explanation: Every SSL certificate and private key pair shares the same modulus. This tool extracts the modulus portion from both the certificate and the private key and performs a SHA-256 hash calculation on it.
- Result Determination: As long as the hash values of both are completely identical, it proves they are a mathematically perfect match.
B. Extensive Format Support
- Certificate Files: Supports formats like
.crt, .pem, .cer, .pub.
- Private Key Files: Supports formats like
.key, .pem (typically starting with -----BEGIN PRIVATE KEY----- or -----BEGIN RSA PRIVATE KEY-----).
C. Absolute Privacy Protection (Local Computation)
- Core Security Policy: All verification logic is completed locally in your browser.
- No-Upload Principle: Your private key information (the most critical asset for server security) is never sent to our servers. The entire comparison process is completed instantly in local memory and destroyed upon page refresh, ensuring maximum security.
3. Verification Status Explanation
| Check Item |
Status |
Meaning |
| Modulus Hash |
Match |
Congratulations! The certificate and private key match perfectly and are safe to deploy. |
| Modulus Hash |
Mismatch |
Warning! The two do not belong to the same key pair. Deployment will cause errors. |
| File Format Detection |
Unparseable |
The input content does not contain valid Base64 certificate or private key identifiers. |
4. Brief Operation Process
- Prepare Files: Open your certificate file (.crt) and private key file (.key) using a text editor (like Notepad, VS Code).
- Input Content:
- Paste the certificate content (including the
BEGIN CERTIFICATE tags) into the first input box.
- Paste the private key content (including the
BEGIN PRIVATE KEY tags) into the second input box.
- Click Verify: Click the "Start Comparison" button.
- View Result: The system will instantly display the SHA-256 modulus fingerprints of both. If the background turns green, it indicates a successful match.
5. Why Choose This Site's Matching Assistant?
- Security First: Uses pure front-end technology (CryptoJS/Forge), eliminating concerns about private key leakage.
- Simple & Intuitive: Eliminates cumbersome OpenSSL command-line operations (like
openssl x509 -noout -modulus...), offering a more user-friendly visual interface.
- Real-time Response: Get results instantly, no upload or download required.
- Completely Free: No login required, unlimited usage. An essential tool for every sysadmin's bookmarks.