The scope of the present document is to recommend a framework for the secure provision of Lawful Interception (LI) and Data Retention (DR) services of a Communication Service Provider (CSP) towards the Law Enforcement Agencies. This framework aims to guarantee security in terms of confidentiality@ integrity@ forward secrecy@ forward integrity and non-repudiation within CSP's LI and DR systems@ operations and CSP internal and external interfaces for the delivery of IRI@ CC and DR data towards any LEAs. The present document initially describes the assets to be protected and then analyses the related security threats. Finally it recommends a range of security measures and controls necessary for achieving the desired level of security. The security measures content contains an unbreakable set of security categories where most of the measures@ for each category@ are indispensable controls while some others can be optionally chosen for creating a tighter security framework. Annexes are also defined. Annex A lists all recommended measures and controls@ associates these measures with the respective systems@ services and interfaces and also with the respective threats that aims to overcome. Annex B provides a secure logging infrastructure. Annex C provides a solution for protecting the retained data during the operation of the DR service while annex D provides a guide for cryptographic algorithms.