Device and method for transmitting data in an encrypted manner

A method for operating a device for transmitting data between two semiconductor chips of a data processor in an encrypted manner, comprising the steps of:

• providing the device which is configured for transmitting in an encrypted manner comprises a non-volatile memory element in each of the two semiconductor chips, wherein an encryption initial value for an encryption rule is stored in the memory element of the first semiconductor chip and a decryption initial value associated to the encryption initial value of a decryption rule associated to the encryption rule is stored in the memory element of the semiconductor chip, wherein the first semiconductor chip comprises a first data transmission interface formed to generate an encryption data stream from an input data stream using the encryption initial value according to the encryption rule, and wherein the second semiconductor chip comprises a second data transmission interface formed to receive the encryption data stream and to determine a decryption data stream from the encryption data stream using the decryption initial value according to the decryption rule and to compare the decryption data stream determined to an expected data stream, wherein the second data transmission interface is also formed to take a defensive measure against transmitting data from the second data transmission interface to the first data transmission interface when the decryption data stream does not correspond to an expected data stream;
• encrypting data of the input data stream in the first data transmission interface using the encryption initial value according to the encryption rule to generate the encryption data stream;
• transmitting the encryption data stream from the first data transmission interface to the second data transmission interface;
• decrypting the encryption data stream in the second data transmission interface using the decryption initial value according to the decryption rule to determine the decryption data stream;
• and
• taking a defensive measure against a transmission of data from the second data transmission interface to the first data transmission interface when the decryption data stream does not correspond to an expected data stream.

A method for personalizing a device for transmitting data between two semiconductor chips of a data processor in an encrypted manner, comprising the steps of:

• providing the device which is configured for transmitting in an encrypted manner comprises a non-volatile memory element in each of the two semiconductor chips, wherein an encryption initial value for an encryption rule is stored in the memory element of the first semiconductor chip and a decryption initial value associated to the encryption initial value of a decryption rule associated to the encryption rule is stored in the memory element of the second semiconductor chip, wherein the first semiconductor chip comprises a first data transmission interface formed to generate an encryption data stream from an input data stream using the encryption initial value according to the encryption rule, and wherein the second semiconductor chip comprises a second data transmission interface formed to receive the encryption data stream and to determine a decryption data stream from the encryption data stream using the decryption initial value according to the decryption rule and to compare the decryption data stream determined to an expected data stream, wherein the second data transmission interface is also formed to take a defensive measure against a transmission of data from the second data transmission interface to the first data transmission interface when the decryption data stream does not correspond to an expected data stream;
• providing the encryption initial value and a decryption initial value associated to the encryption initial value;
• storing the encryption initial value into the non-volatile memory element of the first semiconductor chip and the decryption initial value into the non-volatile memory element of the second semiconductor chip;
• and
• protecting the encryption initial value stored in the non-volatile memory element of the first semiconductor chip and the decryption initial value stored in the non-volatile memory element of the second semiconductor chip against alteration.

A computer program having a program code for performing a method for operating a device for transmitting data between two semiconductor chips of a data processor in an encrypted manner, wherein the device for transmitting in an encrypted manner comprises a non-volatile memory element in each of the two semiconductor chips, wherein an encryption initial value for an encryption rule is stored in the memory element of the first semiconductor chip and a decryption initial value associated to the encryption initial value of a decryption rule associated to the encryption rule is stored in the memory element of the semiconductor chip, wherein the first semiconductor chip comprises a first data transmission interface formed to generate an encryption data stream from an input data stream using the encryption initial value according to the encryption rule, and wherein the second semiconductor chip comprises a second data transmission interface formed to receive the encryption data stream and to determine a decryption data stream from the encryption data stream using the decryption initial value according to the decryption rule and to compare the decryption data stream determined to an expected data stream, wherein the second data transmission interface is also formed to take a defensive measure against transmitting data from the second data transmission interface to the first data transmission interface when the decryption data stream does not correspond to an expected data stream, and wherein the method for operating the device for transmitting in an encrypted manner comprises the steps of:

• encrypting data of the input data stream in the first data transmission interface using the encryption initial value according to the encryption rule to generate the encryption data stream;
• transmitting the encryption data stream from the first data transmission interface to the second data transmission interface;
• decrypting the encryption data stream in the second data transmission interface using the decryption initial value according to the decryption rule to determine the decryption data stream;
• and taking a defensive measure against a transmission of data from the second data transmission interface to the first data transmission interface when the decryption data stream does not correspond to an expected data stream, when the computer program runs on a computer.

A computer program having a program code for performing a method for personalizing a device for transmitting data between two semiconductor chips of a data processor in an encrypted manner, wherein the device for transmitting in an encrypted manner comprises a non-volatile memory element in each of the two semiconductor chips, wherein an encryption initial value for an encryption rule is stored in the memory element of the first semiconductor chip and a decryption initial value associated to the encryption initial value of a decryption rule associated to the encryption rule is stored in the memory element of the second semiconductor chip, wherein the first semiconductor chip comprises a first data transmission interface formed to generate an encryption data stream from an input data stream using the encryption initial value according to the encryption rule, and wherein the second semiconductor chip comprises a second data transmission interface formed to receive the encryption data stream and to determine a decryption data stream from the encryption data stream using the decryption initial value according to the decryption rule and to compare the decryption data stream determined to an expected data stream, wherein the second data transmission interface is also formed to take a defensive measure against a transmission of data from the second data transmission interface to the first data transmission interface when the decryption data stream does not correspond to an expected data stream, and wherein the method for personalizing the device for an authenticated transmission includes the steps of:

• providing the encryption initial value and a decryption initial value associated to the encryption initial value;
• storing the encryption initial value into the non-volatile memory element of the first semiconductor chip and the decryption initial value into the non-volatile memory element of the second semiconductor chip;
• and protecting the encryption initial value stored in the non-volatile memory element of the first semiconductor chip and the decryption initial value stored in the non-volatile memory element of the second semiconductor chip against alteration, when the computer program runs on a computer.