Web Security
Check SSL/TLS certificate details including issuer, expiration date, days remaining, validity, and security grade.
An SSL/TLS certificate is a digital document that binds a cryptographic key to an identity (domain name, organization, or both). It enables encrypted communication between a web server and browser, ensuring that data in transit cannot be intercepted or tampered with. The certificate also verifies that the server you are connecting to actually owns the domain it claims, preventing impersonation attacks. Despite the name SSL, modern certificates use TLS (Transport Layer Security), the successor protocol.
For security professionals, SSL certificate analysis reveals critical infrastructure information: who issued the certificate, when it was issued, when it expires, which domain names it covers, and whether the certificate chain is valid. Expired, misconfigured, or suspicious certificates are common findings in security assessments and can indicate compromised infrastructure, phishing operations, or mismanaged security.
This tool inspects a domain's SSL certificate in detail, checking validity, expiration, issuer reputation, protocol support, and cipher suite strength. It provides a security grade based on the overall TLS configuration, helping you quickly assess whether a site's encryption meets current standards.
Expired or soon-to-expire certificates are immediate security concerns. An expired certificate triggers browser warnings that users often ignore or click through, creating a false sense of insecurity. Worse, an expired certificate may indicate neglected infrastructure management, suggesting that other security controls may also be unmonitored. Regular certificate monitoring prevents expiration surprises.
Certificate issuer analysis reveals whether a certificate was issued by a trusted Certificate Authority (CA) or a less reputable provider. Free CAs like Let's Encrypt are legitimate and widely trusted, but they are also commonly used by phishing sites because they are easy to obtain. A certificate from an unexpected CA for a high-profile domain warrants investigation.
Certificate Transparency (CT) logs publicly record every certificate issued for a domain. By checking CT logs, you can discover unauthorized certificates issued for your domain, which may indicate compromise or misconfiguration. CT monitoring is a critical part of domain security for any organization that operates web services.
The TLS protocol version and cipher suites determine the strength of encryption. TLS 1.0 and 1.1 are deprecated and should never be used. TLS 1.2 is secure when configured with strong cipher suites, while TLS 1.3 offers improved performance and security by removing legacy algorithms. This tool reports which protocol versions a server supports, helping you identify outdated configurations.
Cipher suites define the algorithms used for key exchange, bulk encryption, and message authentication. Weak cipher suites like those using RC4, DES, or export-grade cryptography are vulnerable to known attacks. Modern best practice uses AES-GCM or ChaCha20-Poly1305 with ECDHE or DHE key exchange. The security grade reflects the strength of supported cipher suites.
Perfect Forward Secrecy (PFS) is a critical property of modern TLS. When PFS is enabled, compromising a server's private key does not compromise past session traffic. This tool checks for PFS support, which is indicated by ephemeral key exchange methods like ECDHE. Without PFS, a recorded encrypted session can be decrypted retroactively if the private key is later obtained.