What is ISO 18033-1 about?
The ISO/IEC 18033 series specifies encryption systems for the purpose of data confidentiality. The inclusion of encryption systems in ISO 18033-1 is intended to promote their use as reflecting the current state of the art in encryption systems.
ISO 18033-1 is general in nature and provides definitions that apply in subsequent parts of the ISO 18033 series. ISO 18033-1 introduces the nature of encryption and describes certain general aspects of its use and properties.
Who is ISO 18033-1 for?
ISO 18033-1 on encryption algorithms is useful for:
- Cybersecurity teams
- Software teams
- IT-based organizations who are looking to improve their security
- Any organization that wants to protect its data
Why should you use ISO 18033-1?
Encryption systems protect the confidentiality of your stored or transmitted data. There are multiple encryption algorithms that serve different purposes and provide differing levels of security.
ISO 18033-1 introduces you to the terminologies and symbols that would be useful for you when you refer to other parts of the ISO 18033 series to implement information security. By providing this information, ISO 18033-1 gives you clarity on information security.
ISO 18033-1 explains various encryption algorithms and their properties, to help you understand where they are best suited for use.
What’s changed since the last update?
BS ISO/IEC 180331:2021 cancels and replaces the second edition (ISO/IEC 18033‑1:2015), which has been technically revised. The main changes compared with the previous edition are as follows:
- Clause 3 has been refined
- Criteria for submission of encryption systems have been refined for possible inclusion in the ISO/IEC 18033 series
- The use and security properties of encryption algorithms have been clarified

