Decryption

Decryption is the reverse of encryption: converting ciphertext back into plaintext using the appropriate key. In symmetric schemes the same key encrypts and decrypts; in asymmetric schemes the holder of the private key decrypts what was encrypted with the matching public key. Authorised decryption depends on rigorous key management; unauthorised decryption is the goal of cryptanalysis.

Categories: Core NetworkSecurity ControlsInternet and Routing

Decryption in context

The mobile core carries subscriber sessions, mobility and policy. In 4G it is the EPC (MME, HSS, S/PGW); in 5G it is the Service-Based Architecture with AMF, SMF, UPF, AUSF, UDM and the NRF.

Security controls span signaling firewalls (SS7/Diameter/GTP screening), transport encryption (IPsec, TLS, PRINS), identity and access on OSS/BSS, and monitoring at both packet and log level. Controls are audited against GSMA FS.11/FS.19/FS.20/FS.36.

To place Decryption in the wider telecom-security picture, review Authorization, SCP, DNN, 3G, 5G SBA and ACL — each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

More from the TelcoSec Glossary

Browse the full TelcoSec Glossary, the Ultimate Guide to Mobile Network Security, or the P1 Arsenal of telecom-security tools.