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Blog Security SSL vs TLS – What’s the Difference?


MARCH 1 2023


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Difference Between Secure Socket Layer (SSL) and Transport Layer Security (TLS)

TLS and SSL are constantly used in combination with each other. On the Internet, you can often find the abbreviation TLS / SSL. But these two terms represent different things.

A Brief History of SSL and TLS

SSL was originally developed by Netscape to add HTTPS to its Netscape Navigator web browser. The beginning of the development put the company’s view that a secure connection between the client and the server in the first place will serve as a success in the development of the Internet as a business tool.

Due to the inability to guarantee the security of the network through which information is transmitted, the best way to protect it was chosen to encrypt and decrypt at the ends of the connection being established, respectively. Netscape could have built this approach directly into their browser security, but that wouldn’t have provided a one-size-fits-all solution. In this case, other applications would not be able to use SSL protocols, which would significantly affect the use of this solution in other products. A more general, application-independent approach was required.

Versions of SSL 1.0-3.0, like all early attempts to create an effective encryption algorithm, were criticized due to the presence of serious security problems, and therefore required the release of several revised versions with improved security architecture.

In 1999, version 1.0 of the Transport Layer Security TLS protocol was released. The name was changed to emphasize the open nature of the standard, so that anyone can use it in their projects, and thereby separate it from Netscape’s proprietary product. Also, TLS was designed to be application agnostic, while SSL was originally intended to be used only for HTTP connections.

SSL vs TLS History

Should You Be Using SSL or TLS?

SSL 2.0 was phased out in 2011 with the release of RFC 6176. In 2014, a POODLE attack was proposed against SSL 3.0 block ciphers and the only supported stream cipher RC4 had other security issues as it was used. In June 2015, SSL 3.0 was deprecated.

In 2018, the PCI DSS regulatory compliance urged corporations to move away from TLS 1.0 and in October 2018, major players in the browser and OS market announced that they would stop supporting TLS versions 1.0 and 1.1 in March 2020.

As you can see, all versions of SSL today are recognized as insecure, as well as versions TLS 1.0 – TLS 1.1. Therefore, it is worth using protocol versions starting from TLS 1.2.

Certificates Are Not the Same as Protocols

An SSL certificate is a digital certificate that authenticates a website and allows an encrypted connection. The abbreviation SSL stands for Secure Sockets Layer, a security protocol that creates an encrypted connection between a web server and a web browser.

A security protocol is an abstract or concrete protocol that includes a set of algorithms and sequences of cryptographic primitives. The protocol is based on a set of rules governing the use of cryptographic transformations and algorithms in information processes for the exchange of messages between two or more participants, as well as a description of the structures used. In a protocol, participants can be applications, users, their groups, or organizations. In other words, everything that, for whatever reason, is capable of playing an active or passive role in the operation of the protocol.

The digital certificate confirms that the public key belongs to some subject. The SSL certificate or TLS certificate contains the name of the subject, the public key, the name of the certification authority CA that issued this certificate, the policy for using the private key corresponding to the public key being certified, and other parameters certified by the digital signature of the certification authority.

Differences Between SSL and TLS

If we compare TLS vs SSL, as noted earlier, TLS has, in a sense, become an extension of SSL. However, there are difference between SSL and TLS.

Cipher Suites

  • Message authentication: TLS uses HMAC, which works with any hash function. SSL configured only for MD5 or SHA.
  • Key generation: in TLS the pseudo-random function of the HMAC standard is used to generate the key. In SSL – RSA, Diffie-Hellman or Fortezza/DMS.
  • Message encryption: SSL only supports RSA, Diffie-Hellman, and Fortezza/DMS algorithms. TLS has dropped support for Fortezza/DMS, but new encryption protocols may be added in future releases.

Alert Messages

Alert Massages are service messages sent to notify you of an error or a change in connection conditions. There are such messages in both protocols, but there is an important key difference. In TLS, such messages are encrypted, while in SSL such messages are transmitted without encryption. Therefore, SSL alert messages can be intercepted by anyone, while in TLS only the sender and recipient can receive data from such messages.

Record Protocol

The protocol that encapsulates the data that is being transmitted is called the record protocol. It is a layered protocol. At each level, messages can include fields with values ​​for the length of the message, its description, and, in fact, the content of the message. In SSL, this protocol is called the SSL Record Protocol. This protocol was developed by the private company Netscape, which developed SSL. TLS uses the TLS Record Protocol, which has been standardized by the Internet Engineering Task Force IETF.

Handshake Process

The process of establishing a connection between two participants in an SSL and TLS session is called the Handshake Process. SSL has two stages of establishing a connection: “Full Hand-shake” and “Abbreviate Handshake”. In TLS, in turn, the connection establishment process occurs in one stage. It’s called “Full Handshake”. In versions of the TLS protocol TLS 1.2 and newer this process has been improved. It becomes noticeably faster by reducing some steps in algorithm.

Message Authentication

Message authentication in both protocols is carried out using hash functions, but there is difference between SSL and TLS here as well. The SSL protocol uses the MD5 cryptographic hashing algorithm. The TLS protocol uses HMAC. This difference is due to the fact that TLS tried to eliminate the security vulnerabilities that SSL has. The MD5 algorithm has become not secure because it is vulnerable to collision attacks.

Message Authentication

How TLS and SSL Secure Data?

Secure Sockets Layer SSL and Transport Level Security TLS are both security protocols that provide secure data transmission over computer networks. They are widely used in web browsers, email, instant messaging, and VoIP.

A connection secured by these protocols has one or more of the following properties:

  • Security: symmetric encryption protects the transmitted information from unauthorized access by unauthorized persons. For example, the AES encryption with key length 256bits is widely used now.
  • Authentication: With digital SSL certificates, the identity of the party to a connection can be verified using asymmetric encryption.
  • Integrity: Cryptographic features provide a way for each message to contain a Message Authentication Code MAC that can verify that the data has not been altered or lost in transit.


Since most data transfer protocols can be used with or without TLS/SSL, when establishing a connection, you must explicitly tell the server whether the client wants to establish a TLS connection to start the key exchange process and get a secure connection.

In the TLS 1.3 protocol, significant attention is paid to the task of hiding metainformation. Meta-information is understood as a set of such information about a TLS connection that allows you to indirectly judge the data transmitted in a secure mode. For example, meta-information includes information about the public cryptographic keys of nodes, connection time, addresses, node names, and so on.


SSL and TLS continue to be used as a term for a secure Internet connection between client and server. The TLS security protocol continues to be considered secure and reliable. However, much depends on the correct implementation and configuration of the protocol. Helenix has unique experience in deploying cryptographic protocols and security systems. You can learn more about it by visiting the Custom Development section.


Secure Socket Layer SSL is a cryptographic protocol that provides secure data transmission over a computer network. It is widely used in web browsers, as well as in e-mail, instant messaging and IP telephony.

Transport Level Security TLS, like its predecessor SSL, is a cryptographic protocol that provides secure data transfer between nodes on the Internet. TLS uses asymmetric encryption for authentication and key exchange, symmetric encryption for privacy, and message authentication codes to preserve message integrity.

The use of SSL 2.0 was discontinued in 2011. In 2014, the POODLE attack was proposed against SSL 3.0 block ciphers, and the only supported stream cipher, RC4, had other security issues as it was used. In June 2015, SSL 3.0 was deprecated and the usage of TLS recommended.

If we compare TLS vs SSL, currently all versions of SSL are recognized as insecure. Therefore, it is better to use TLS 1.2 and newer versions. They remain secure as they use stronger cryptographic algorithms and protection mechanisms than those used in SSL.

To determine the type of certificate, you need to open the certificate details. There you will see tabs containing information about the party that issued the certificate and whether it is SSL certificate or TLS certificate.