Method for signing a message, in which a control center and the receiver share a permanent, main key. The control center produces a sequence number, and a signing key from this by means of a one-time function. Both are provided in secure form to the sender. The sender uses the signing key to form a signature for the message, forms a data set, and sends the data set containing the signature, the sequence number and the message, to the receiver. The receiver uses a one-way function, main key and sequence number to form a check key, and thus checks the signature on the message.