NULL encryption algorithm
An algorithm [R2410] that is specified as doing nothing to transform plaintext data; i.e., a no-op. It originated because ESP always specifies the use of an encryption algorithm for confidentiality. The NULL encryption algorithm is a convenient way to represent the option of not applying encryption in ESP (or in any other context where a no-op is needed). (Compare: null.)
Senses
(I)
An algorithm [R2410] that is specified as doing nothing to transform plaintext data; i.e., a no-op. It originated because ESP always specifies the use of an encryption algorithm for confidentiality. The NULL encryption algorithm is a convenient way to represent the option of not applying encryption in ESP (or in any other context where a no-op is needed). (Compare: null.)
References
- IETF RFC 4949 (Internet Security Glossary)Jan 06, 2026RFC 4949 — Internet Security Glossary (Version 2)https://www.rfc-editor.org/rfc/rfc4949.txtRFC 4949 is published by the IETF Trust and marked as "Distribution of this memo is unlimited". Verify IETF Trust copyright/licensing terms for reuse.Source: IETF RFC 4949 (rfc-editor.org).