AMF Reassignment Using Encrypted Security Context Transfer
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Solution Overview
Problem
In the 5G communication system, the transfer of security context during AMF reallocation between the UE and the target AMF is insecure, leading to registration failures and vulnerability to cryptographic attacks, as the target AMF lacks the necessary security context and cannot verify the reliability of the initial AMF.
Innovation Solution
The security context is transferred from the initial AMF to the target AMF using an asymmetric encryption scheme, ensuring the context is protected and verifiable, thereby enabling secure registration and preventing replay attacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If security context is transferred during AMF reallocation without asymmetric encryption, then the transfer process is simple and fast, but the security is compromised and vulnerable to cryptographic attacks
Solution Approach 1:
The patent introduces an asymmetric encryption scheme as an intermediary mechanism between the initial AMF and target AMF during security context transfer. The initial AMF encrypts the security context using the target AMF's public key, and the target AMF decrypts it using its private key. This intermediary encryption layer ensures secure transfer while maintaining a standardized, manageable complexity through well-established cryptographic protocols.
Solution Approach 2:
The patent applies preliminary action by pre-establishing asymmetric key pairs for both the initial AMF and target AMF before the reallocation process begins. The public keys are exchanged in advance, enabling the encrypting party to securely transmit the security context without requiring real-time key generation or complex negotiation during the actual transfer, thus reducing operational complexity while maintaining high security.
2Reliability
If asymmetric encryption is used for security context transfer, then security and reliability are improved, but the processing time and computational overhead increase
Solution Approach 1:
The asymmetric key pairs are established and public keys exchanged before the reallocation event occurs. This preliminary setup eliminates the need for time-consuming key generation and exchange during the actual security context transfer, reducing latency while maintaining the security benefits of asymmetric encryption.
Solution Approach 2:
The patent segments the security context transfer process into distinct phases: encryption of the security context by the initial AMF using the target AMF's public key, transmission of the encrypted context, and decryption by the target AMF using its private key. This segmentation allows for optimized processing at each stage and enables parallel operations where possible, reducing overall transfer time while maintaining security.
Data Source
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AI summary
A method for carrying out AMF reassignment in a communication system may comprise the steps of: transmitting, to an NSSF, a first request message including at least one of a first parameter for requesting a public key of an AMF that is to be reassigned and a second parameter for requesting a token related to the AMF that is to be reassigned; receiving, from the NSSF, a first response message including at least one of information indicating a target AMF set, and a public key of the target AMF set or the token; generating, on the basis of first security context for user equipment, an SC container including second security context for a target AMF; encrypting the SC container by using the public key; and transmitting, to the target AMF via a radio access network related to the user equipment, at least one of the encrypted SC container, additional information related to encryption of the SC container, and the token.