SSL Certificate Checker

About SSL Certificates

SSL certificates are digital certificates used to encrypt data communication over the Internet and ensure the trustworthiness of websites. This allows users to browse sites and transmit data securely. SSL certificates are issued by a Certificate Authority (CA) and contain important information such as the issuer, subject, serial number, and expiration date. This tool allows you to easily check the SSL certificate information for a specified domain and verify its validity and expiration date.

Glossary of Terms Related to SSL Certificates

SSL Certificate:

A digital certificate used to enhance website security by encrypting communication and verifying the site's trustworthiness.

Expiration Date:

The period during which the SSL certificate is valid. Once expired, the certificate becomes invalid.

Issuer:

The Certificate Authority (CA) that issued the SSL certificate and guarantees its validity.

Subject:

The entity (usually the domain) to which the SSL certificate was issued.

Serial Number:

A unique identifier for the SSL certificate used for tracking and management.

Signature Algorithm:

The algorithm used to create the digital signature of the SSL certificate to prevent tampering.

Extended Key Usage:

A field in the SSL certificate that defines its specific purposes, such as server authentication or email protection.

Subject Alternative Name:

Additional domain names or IP addresses included in the SSL certificate to cover multiple domains.

Basic Constraints:

A field that defines the policy for issuing the SSL certificate, including whether it can act as a CA.

CRL Distribution Points:

A field indicating the location of the Certificate Revocation List (CRL) to check for revoked certificates.

Certificate Policies:

A field indicating the policy of the SSL certificate, including specific usage conditions and restrictions.

Authority Information Access:

A field providing access to information about the CA, used for verifying the certificate chain.

Authority Key Identifier:

An identifier corresponding to the CA's public key, used for verifying the certificate chain.

Subject Key Identifier:

An identifier corresponding to the subject's public key, used to ensure certificate consistency.