Secure Transmission of a Message

A device for producing a secure transmission of a message, the device comprising:

• a first unit generating a base key by a key unit;
• a second unit for generating a sender key for at least one sender by the key unit by means of a key derivation function on the basis of (i) the base key, and (ii) an identifier which that uniquely identifies the at least one sender;
• a third unit for transmitting the sender key to the at least one sender;
• a fourth unit for calculating a first cryptographic checksum by the at least one sender for the message on the basis of the sender key and the message;
• a fifth unit for transmitting the message together with the first cryptographic checksum to a receiver;
• a sixth unit for transmitting the base key to the receiver;
• a seventh unit for producing a receiver key by the receiver by means of the key derivation function on the basis of (i) the base key, and (ii) the identifier of the sender of the message;
• an eighth unit for generating a second cryptographic checksum for the message by the receiver on the basis of the receiver key and the message;
• a ninth unit for checking the integrity of the message by comparing the first cryptographic checksum with the second cryptographic checksum, where the integrity of the message is given if the first cryptographic checksum and the second cryptographic checksum are identical.

A device (DEV) for producing a secure transmission of a message, the device comprising:

• a first unit for generating a base key by a key unit;
• a second unit for generating a sender key for at least one sender by the key unit by means of a key derivation function on the basis of (i) the base key, and (ii) an identifier that uniquely identifies the at least one sender;
• a third unit for transmitting the sender key to the at least one sender;
• a fourth unit for calculating a first cryptographic checksum by the at least one sender for the respective message on the basis of the sender key and the message;
• a fifth unit for transmitting the message together with the first cryptographic checksum to a receiver;
• a sixth unit for transmitting the base key to the receiver;
• a seventh unit for producing a receiver key by the receiver by the key derivation function on the basis of (i) the base key, and (ii) the identifier of the sender of the message;
• an eighth unit for generating a second cryptographic checksum for the message the receiver on the basis of the receiver key and the message;
• a ninth unit for checking the integrity of the message by comparing the first cryptographic checksum with the second cryptographic checksum, where the integrity of the message is given if the first cryptographic checksum and the second cryptographic checksum are identical.