The absence of security in Signalling System No. 7 (SS7) networks is an identified security weakness in 2G systems. This was formerly perceived not to be a problem, since the SS7 networks were the provinces of a small number of large institutions. This is no longer the case, and so there is now a need for security precautions. For 3G systems it is a clear goal to be able to protect the core network signalling protocols, and by implication this means that security solutions shall be found for both SS7 and IP based protocols. Various protocols and interfaces are used for control plane signalling within and between core networks. The security services that have been identified as necessary are confidentiality, integrity, authentication and anti-replay protection. These will be ensured by standard procedures, based on cryptographic techniques.

This technical specification covers the security mechanisms and procedures necessary to protect all TCAP user messages which are sent between different security domains. The complete set of enhancements and extensions to facilitate security protection for the TCAP protocol is termed TCAPsec and it covers transport security in the TCAP protocol itself and the security management procedures. This technical specification contains the stage 2 specification for security protection of the TCAP protocol. The actual implementation (stage 3) specification can be found in TS 29.204.

The following documents contain provisions which, through reference in this text, constitute provisions of the present document.

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