And how do they increase trust in websites?


SSL: Secure Sockets Layer

SSL is standard technology for securing an internet connection by encrypting data sent between a website and a browser (or between two servers). It prevents hackers from seeing or stealing any information transferred, including personal or financial data.

Related Terms

TLS: Transport Layer Security

TLS is an updated, more secure version of SSL. We still refer to our security certificates as SSL because it’s a more common term, but when you buy SSL from DigiCert, you get the most trusted, up-to-date TLS certificates.

HTTPS: Hyper Text Protocol Secure

HTTPS appears in the URL when a website is secured by an SSL/TLS certificate. Users can view the details of the certificate, including the issuing authority and the corporate name of the website owner, by clicking the lock symbol on the browser bar.

SSL Improves SEO

In 2014, Google called for HTTPS everywhere to improve security across the web — and they rewarded SSL-secured sites with higher rankings. In 2018, Google went beyond search rankings and began punishing sites without SSL certificates by flagging them as “not secure” in the Chrome browser.

How Does SSL Increase Trust?

Not all SSL certificates are created equal. Beyond encrypting data with SSL, DigiCert also authenticates the identity of website owners to add another layer of security. We offer certificates with three levels of validation:

Domain Validation SSL Certificates

Organization Validation SSL Certificates

Extended Validation SSL Certificates

How Do SSL Certificates Work?

SSL certificates establish an encrypted connection between a website/server and a browser with what’s known as an “SSL handshake.” For visitors to your website, the process is invisible — and instantaneous.


For every new session a user begins on your website, their browser and your server exchange and validate each other’s SSL certificates.


Your server shares its public key with the browser, which the browser then uses to create and encrypt a pre-master key. This is called the key exchange.


The server decrypts the pre-master key with its private key, establishing a secure, encrypted connection used for the duration of the session.

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SSL Glossary


256-bit encryption Process of scrambling an electronic document using an algorithm whose key is 256 bits in length. The longer the key, the stronger it is.


Asymmetric cryptography Ciphers that imply a pair of two keys during the encryption and decryption processes. In the world of SSL and TLS, we call them public and private keys.


Certificate signing request (CSR) Machine-readable form of a DigiCert certificate application. A CSR usually contains the public key and distinguished name of the requester.

Certificate authority (CA) Entity authorized to issue, suspend, renew or revoke certificates under a CPS (Certification Practice Statement). CAs are identified by a distinguished name on all certificates and CRLs they issue. A CA must publicize its public key or provide a certificate from a higher-level CA attesting to the validity of its public key if it’s subordinate to a Primary Certification Authority. DigiCert is a Primary Certification Authority (PCA).

Cipher suite A set of key exchange protocols, which includes the authentication, encryption and message authentication algorithms used within SSL protocols.

Common name (CN) Attribute value within the distinguished name of a certificate. For SSL certificates, the common name is the DNS host name of the site to be secured. For Software Publisher Certificates, the common name is the organization name.

Connection error Security issues preventing a secure session are flagged when a user tries to access a site.


Domain Validation (DV) SSL Certificates The most basic level of SSL certificate. Only domain name ownership is validated before the certificate is issued.


Elliptic Curve Cryptography (ECC) Creates encryption keys based on the idea of using points on a curve for the public/private key pair. Extremely difficult to break using the brute force methods often employed by hackers and offers a faster solution with less computing power than pure RSA chain encryption.

Encryption Process of transforming readable (plaintext) data into an unintelligible form (ciphertext) so the original data either cannot be recovered (one-way encryption) or cannot be recovered without using an inverse decryption process (two-way encryption).

Extended Validation (EV) SSL Certificates The most comprehensive form of secure certificate. The domain is validated and the company or organization undergoes a strict authentication process.


Key exchange How users and servers securely establish a pre-master secret for a session.


Master secret The key material used for a generation of encryption keys, MAC secrets and initialization vectors.

Message Authentication Code (MAC) A one-way hash function arranged over a message and a secret.


Organization Validation (OV) SSL Certificates A type of SSL certificate that validates ownership of the domain and the existence of the organization behind it.


Pre-master secret The key material used for the master secret derivation.

Public key infrastructure (PKI) Architecture, organization, techniques, practices and procedures that collectively support the implementation and operation of a certificate-based public key cryptographic system. The PKI consists of systems that collaborate to provide and implement the public key cryptographic system, and possibly other related services.


Secure server Server that protects host web pages using SSL or TLS. When a secure server is in use, the server is authenticated to the user. User information is encrypted by the web browser’s SSL protocol before being sent across the internet. Information can only be decrypted by the host site that requested it.

SAN (Subject Alternative Name) SSL certificates Type of certificate that allows multiple domains to be secured with one SSL certificate.

SSL Abbreviation for secure sockets layer. Protocol for web browsers and servers that allows for the authentication, encryption and decryption of data sent over the internet.

SSL certificate Server certificate that enables authentication of the server to the user and encryption of data transferred between the server and the user.

SSL Handshake A protocol used within SSL for the purpose of security negotiation.

Symmetric encryption Encryption method that implies the same key is used both during the encryption and decryption processes.


TCP Transmission control protocol, one of the main protocols in any network.


Wildcard SSL certificates Type of certificate used to secure multiple subdomains.