SSL/TLS Certificate Lifecycle
Understanding the SSL/TLS Certificate Lifecycle
SSL/TLS certificates are crucial for secure online communication. They are issued by Certificate Authorities (CAs) and verify the identity of websites and servers. Each certificate has a lifecycle, starting with a request and ending with expiration or revocation.
Stages
1. Request and Enrollment
A user requests a certificate by submitting a Certificate Signing Request (CSR).
The CSR contains information about the domain name or organization.
The CA validates the request and issues the certificate.
2. Issuance and Provisioning
The CA digitally signs the certificate, confirming its authenticity.
The certificate is installed on the website or server.
3. Usage and Monitoring
The certificate is used for secure communication.
Monitoring systems track certificate usage and status.
Timely renewal or revocation is ensured.
4. Expiration and Renewal
Certificates expire after a certain period.
Renewal is necessary to avoid interruptions.
The certificate holder or CA initiates the renewal process.
A new certificate is issued with a digital stamp.
Effective certificate management is essential for maintaining secure online operations.
CRL
A certificate revocation list (CRL) is a list of digital certificates that have been revoked by the issuing certificate authority (CA) before their actual or assigned expiration date.
It is a type of blocklist that includes certificates that should no longer be trusted and is used by various endpoints, including web browsers, to verify if a certificate is valid and trustworthy.
The CRL file is signed by the CA to prevent tampering.
OCSP
The Online Certificate Status Protocol (OCSP) is an alternative to the certificate revocation list (CRL) and is used to check whether a digital certificate is valid or if it has been revoked.
The OCSP is an Internet Protocol (IP) that certificate authorities (CAs) use to determine the status of secure sockets layer/transport layer security (SSL/TLS) certificates, which are common applications of X.509 digital certificates. This helps web browsers check the status and validity of Hypertext Transfer Protocol Secure (HTTPS) websites.
HTTPS Workflow
1. Client Generates a Symmetric Key:
The client creates a random symmetric key that will be used to encrypt and decrypt the actual data.
2. Client Encrypts Key with Server's Public Key:
The client encrypts the symmetric key using the public key of the server, which is embedded in the server's SSL certificate.
3. Server Decrypts Key with Private Key:
The server receives the encrypted symmetric key and decrypts it using its private key. This process ensures that only the server can access the symmetric key.
4. Secure Channel Established:
Now that both the client and server have the same symmetric key, they can establish a secure, encrypted channel for communication.
5. Data Exchange:
All subsequent data transmitted between the client and server is encrypted using the symmetric key. This ensures that the data remains confidential and protected from eavesdropping.
References
Last updated
