How does SSL and TLS work?

What is SSL?

HTTPS (Secure Sockets Layer) is an abbreviation for Secure Sockets Layer and refers to a protocol used for encrypting and protecting conversations that take place over the Internet. Although SSL has been replaced by a more recent protocol known as TLS (Transport Layer Security) quite some time ago, the term “SSL” is still routinely used to refer to this technology.

SSL/TLS is most commonly used to protect communications between a client and a server, but it can also be used to secure email, VoIP, and other types of communications that take place across insecure networks.

How does SSL/TLS work?

The following are the fundamental principles that must be understood to comprehend how SSL/TLS works:

Using the TLS handshake, two interacting parties can establish a secure connection and exchange their public keys.
Both sides produce session keys during the TLS handshake, and the session keys then encrypt and decrypt all communications that occur after the TLS handshake has been completed.
Each session makes use of a unique session key to encrypt the communications it receives.
TLS verifies that the party on the server-side, or the website with whom the user is communicating, is truly who they claim to be. TLS is used to protect sensitive information such as credit card numbers and passwords.
In addition, because a message authentication code (MAC) is transmitted with each transfer, TLS ensures that data has not been tampered with.
TLS encrypts both the HTTP data that users give to a website (by clicking on links, filling out forms, and so on) and the HTTP data that websites communicate to users (by sending emails). The recipient must use a key to unlock the encrypted data before it can be used.

The TLS handshake

The TLS handshake is the first step in any TLS communication session. In the case of a TLS handshake, asymmetric encryption is utilized, which means that two separate keys are used on both ends of the conversation. Public key cryptography, which makes this possible, is a technique developed by the United States government.

Generally speaking, two keys are used in public-key cryptography: a public key, which the server makes available to the public, and a private key, which is kept secret and is only utilized on the server-side. It is only possible to decrypt data encrypted with the public key if the data is also encrypted with the private key, and vice versa.

Client and server utilize their public and private keys to exchange randomly created data during the TLS handshake, and this randomly generated data is then used to generate new encryption keys for usage in the session, which are referred to as session keys.

Symmetric encryption with session keys

In contrast to asymmetric encryption, symmetric encryption is used when both parties to a discussion share the same encryption key. Following the TLS handshake, both parties encrypt their data using the same session keys. Once the session keys are in use, the public and private keys are no longer required for authentication. The keys associated with a session are only valid for the duration of the session and are not utilized again once it has ended. For each subsequent session, a new set of session keys will be generated at random.

Authenticating the origin server

Symmetric Encryption is a type of encryption that uses two keys to protect data.
Assuring that TLS communications from the server contain a message authentication code, or MAC, which serves as an electronic signature that the transmission came from the actual website. In this way, the server can be authenticated, preventing on-path assaults and domain spoofing. It also assures that the data has not been tampered with throughout the transmission process.

What is an SSL certificate?

An SSL certificate is a file that is put on the origin server of a website. The public key and the identity of the website owner, among other pieces of information, are contained in a data file known as a certificate. The traffic on a website cannot be encrypted with TLS unless the website has an SSL certificate.

The creation of a self-signed SSL certificate is technically possible for any website owner, and such certificates are referred to as self-signed certificates. Self-signed certificates, on the other hand, are not regarded as being as trustworthy as SSL certificates issued by a certificate authority, according to browsers.

How does a website get an SSL certificate?

Website owners must first obtain an SSL certificate from a certificate authority and then install it on their web server for their website to function properly (often a web host can handle this process). A certificate authority is an independent third-party organization that verifies that the website owner is who they claim to be. They retain a duplicate of each of the certifications they provide to their customers.

Is it possible to get a free SSL certificate?

SSL certificates are often charged for by many certificate authorities. Cloudflare provides free SSL certificates to assist in making the Internet more secure. Cloudflare was the first company to do so, and it was a security and performance company on the Internet. Cloudflare has also worked to improve the performance of SSL/TLS certificates, ensuring that websites transitioning from HTTP to HTTPS do not see any performance degradation. More information regarding Cloudflare’s SSL settings may be found in our developer guide.

What is the difference between HTTP and HTTPS?

HTML is an abbreviation for “HTTPS,” which means “secure.” HTTPS is simply HTTP over an SSL/TLS connection. In addition, traffic to and from a website with an HTTPS address is verified and encrypted using the SSL/TLS protocol, which was developed by the National Institute of Standards and Technology (NIST).

Many web browsers have begun to flag HTTP websites as “not secure” or “unsafe” to encourage the entire Internet community to migrate to the more secure HTTPS protocol. Users’ safety and data security are therefore paramount, and HTTPS has become important for establishing and maintaining confidence with customers. SSL/HTTPS concerns on a website should be investigated.