olemus
(a) võrgus edastatavate andmete krüpteerimine
(b) andmete krüpteerimine võrgukihis, vt IPSec

täpsemalt
http://www.blacksheepnetworks.com/security/info/misc/netdesign/encryption.gif

https://www.lifewire.com/introduction-to-network-encryption-817993

https://www.symantec.com/content/dam/symantec/docs/reports/esg-report-network-encryption-and-its-impact-on-network-security.pdf

https://www.symantec.com/content/dam/symantec/docs/white-papers/securosis-security-and-privacy-on-the-encrypted-network.pdf

https://oristel.com.sg/wp-content/uploads/2015/03/Optical-Network-Encryption-A-New-Key-to-Data-Security.pdf
https://www.youtube.com/watch?v=RtYlTGaPqzQ