The purpose of the present document is to specify the rules for the management of the TETRA standard encryption algorithm TEA1. This algorithm is intended for air interface encryption in TETRA products. The specification for TEA1 consists of the following three parts: Part 1: Algorithm specification; Part 2: Design conformance test data; Part 3: Algorithm input/output test data. The procedures described in the present document apply to Parts 1 and 2 of the specifications. Parts 1 and 2 are confidential for each of the algorithms. Part 3 of each of the specifications is not confidential and can be obtained directly from the TEA1 Custodian (see clause 5.2). There are no restrictions on the distribution of this part of the specifications. The management structure is defined in clause 4. This structure is defined in terms of the principals involved in the management of TEA1 (ETSI@ ETSI Technical Committee TCCE@ TEA1 Custodian and approved recipients) together with the relationships and interactions between them. The procedures for delivering TEA1 to approved recipients are defined in clause 5. This clause is supplemented by annex A which specifies the items which are to be delivered. Clause 6 is concerned with the criteria for approving an organization for receipt of TEA1 and with the responsibilities of an approved recipient. This clause is supplemented by annex B which contains a Confidentiality and Restricted Usage Undertaking to be signed by each approved recipient. Clause 7 is concerned with the appointment and responsibilities of the TEA1 Custodian.