Abstract: A method for replacing an existing key derivation key in a utility meter arranged in a meter communication infrastructure in a secure way. The method provide a secure mechanism for exchange of symmetric keys without the need for transferring keys across the meter communication infrastructure. From the head-end system to the utility meter is transmitted a command data message comprising a request for replacing the existing key derivation key with the new key derivation key, the key-generation information and a activation key or an authentication code calculated based on the activation key. The utility meter receiving the command data message is arranged to derive the new key derivation key based on a copy of a disaster recovery key stored in the utility meter and on the key-generation information comprised in the received command data message. Further, the utility meter is arranged for deriving a activation key from the new key derivation key. The activation key is used for verifying the command data message.

Abstract: A method for replacing an existing key derivation key in a utility meter arranged in a meter communication infrastructure in a secure way. The method provide a secure mechanism for exchange of symmetric keys without the need for transferring keys across the meter communication infrastructure. From the head-end system to the utility meter is transmitted a command data message comprising a request for replacing the existing key derivation key with the new key derivation key, the key-generation information and a activation key or an authentication code calculated based on the activation key. The utility meter receiving the command data message is arranged to derive the new key derivation key based on a copy of a disaster recovery key stored in the utility meter and on the key-generation information comprised in the received command data message. Further, the utility meter is arranged for deriving a activation key from the new key derivation key. The activation key is used for verifying the command data message.

Abstract: A method is described for access to a directory by an application (410). A function library (412) handles a first request from the application for fetching the information from a server. The first request is forwarded from the function library (412) to the server by a client module (414). A request identifier (420) is sent from the function library to the application when the first request is forwarded to the server. A response signal (422) to the first request is sent from the server and received by the application. The response signal comprises a response identifier. The response identifier is checked to match the response signal (422) to the first request. A function from the function library is called (424) by the application for decoding the response signal. The decoded response signal is returned (426) from the function library to the application. A device and a program are also described.