What is a security algorithm?

Encryption is an essential part of a technology. It ensures the effective and secure authentication of users. A security algorithm is a mathematical procedure used to encrypt data. Information is encoded and requires the use of a software key to transform the data back into its original form.

Our world-leading expertise in security algorithms

Our Security Algorithms Group of Experts (SAGE) provides our standards-makers with cryptographic algorithms and protocols specific to:

  • fraud prevention
  • unauthorized access to public and private telecommunications networks
  • user data privacy

Much of the group’s work in recent years has been in support of mobile telecommunications security.

Custodian of algorithms

ETSI is the custodian (distributing authority) of various algorithms. As custodian, we handle licensing of the algorithms and distribution of the relevant specifications and other confidential information. To use certain algorithms, written authorization may be required and a fee may be payable. Additional authorizations, typically concerning Intellectual Property Rights, may also be necessary.

ETSI algorithms

A list of the algorithms we have developed ourselves is available on our website. This list includes conditions for their use and how to obtain them.

Custodian of other algorithms

We also act as custodian for algorithms produced by other organizations:

  • Various cellular algorithms:
    • the A5/4 and A5/3 encryption algorithms for GSM™ and EDGE and the GEA4, GEA3 and GEA2 encryption algorithms for the General Packet Radio Service (GPRS), which we developed in collaboration with the Alliance for Telecommunications Industry Solutions (ATIS) and the GSM Association.
    • the 3GPP™ confidentiality and integrity algorithms UEA2 & UIA2, UEA1 & UIA1 and EEA3 & EIA3, EEA2 & EIA2 and EEA1 & EIA1 which we developed in collaboration with the Association of Radio Industries and Businesses (ARIB), the Telecommunications Technology Association (TTA) and ATIS.
    • the 3GPP authentication and key generation algorithms, TUAK (based on the KECCAK hash function family) and MILENAGE.

Information about these algorithms and their use can be found on the 3GPP website.

Applying for a license

Companies may be licensed to use these algorithms in the manufacture or development of products and services. The steps required to obtain such a licence are set out in a series of agreements:


We assign and manage codes for various technologies. These codes are used, for example, to identify the manufacturer, installer or operator of communication systems.

For further information, please contact us.