SSL/TLS Certificate Checker Guide

Learn how to check SSL/TLS certificates and analyze website security. This comprehensive guide covers certificate validation, security analysis, and best practices.

What is SSL/TLS?

SSL (Secure Sockets Layer) and TLS (Transport Layer Security) are cryptographic protocols that provide secure communication over a computer network. They encrypt data between web browsers and servers, ensuring privacy and data integrity.

How to Use the SSL Checker

Navigate to the SSL/TLS Checker tool
Enter the domain name or IP address to check
Select the port (default: 443 for HTTPS)
Click "Check Certificate" to analyze
Review the certificate details and security status
Check for any security warnings or issues
Export the certificate information if needed

Certificate Information Explained

Basic Information

Subject: Certificate owner details
Issuer: Certificate Authority (CA)
Serial Number: Unique certificate identifier
Version: Certificate format version

Validity Period

Valid From: Certificate start date
Valid To: Certificate expiration date
Days Remaining: Time until expiration
Status: Valid, expired, or revoked

Security Analysis

Security Checks Performed

Certificate Validity: Check if certificate is valid and not expired
Chain of Trust: Verify certificate chain to trusted root CA
Key Strength: Analyze encryption key length and algorithm
Protocol Support: Check supported TLS/SSL versions
Cipher Suites: Analyze available encryption methods
HSTS Support: Check for HTTP Strict Transport Security

Certificate Types

Domain Validated (DV)

Basic validation, only verifies domain ownership. Fast and cheap.

Organization Validated (OV)

Validates organization identity. Shows company name in certificate.

Extended Validation (EV)

Highest validation level. Shows green address bar in browsers.

Common Security Issues

⚠️ Security Warnings

Expired Certificate: Certificate has passed its validity period
Self-Signed Certificate: Not issued by a trusted Certificate Authority
Weak Encryption: Using outdated or weak encryption algorithms
Mixed Content: HTTPS page loading HTTP resources
Certificate Mismatch: Certificate doesn't match the domain name
Revoked Certificate: Certificate has been revoked by the CA

Best Practices

SSL/TLS Best Practices

Use strong encryption algorithms (AES-256, RSA-2048+)
Enable HSTS (HTTP Strict Transport Security)
Use modern TLS versions (TLS 1.2 or 1.3)
Implement proper certificate chain
Monitor certificate expiration dates
Use automated certificate renewal

Certificate Monitoring

Monitoring and Maintenance

Expiration Alerts: Set up notifications before certificates expire
Regular Checks: Periodically verify certificate status
Automated Renewal: Use tools like Let's Encrypt for automatic renewal
Backup Certificates: Keep secure backups of certificates and private keys
Security Updates: Stay updated with latest TLS/SSL security advisories