Chip card or security module production method in which the chip producer writes an authentication code, such as a cryptographic key, into the chip's non-volatile memory so that the memory can only be accessed using the key

Method for producing security modules, especially chip cards in which the chip producer writes an authentication code such as a secret cryptographic key into the chip memory. Said code cannot be read from the card memory. The operating system is configured such that the memory access is only possible if the authentication code is known. An Independent claim is made for a security module comprising a chip with a ROM mask and a non-volatile memory, whereby the non-volatile memory contains a secret test value that cannot be read out and whereby the memory can only be accessed if the code is known. Die Erfindung schlägt vor, bei der Herstellung eines Chips für eine Chipkarte einen nur dem Chiphersteller bekannten geheimen Schlüssel in einen speziellen Speicherbereich des Chips einzuschreiben. Der geheime Schlüssel des Chip-Herstellers wird dem Abnehmer auf gesichertem Weg geliefert. Nur bei Verwendung des geheimen Schlüssels ist es möglich, Programmcode, Datenstrukturen und Daten in den Speicher des Chips einzubringen.