Patent ID: 7450716

Claim:
A device for encrypting original data, comprising: a first encrypter for encrypting original data using an encryption algorithm and an encryption key in order to obtain encrypted data; a decrypter for decrypting the encrypted data using a decryption algorithm matched to the encryption algorithm and using a decryption key matched to the encryption key in order to obtain decrypted data; an auxiliary key calculator for receiving the original data and the decrypted data, and for calculating an auxiliary key using an auxiliary key function, the original data and the decrypted data, wherein the auxiliary key function is implemented in order to provide the encryption key as an auxiliary key when the decrypted data are present in a predetermined relation to the original data and in order to provide an auxiliary key deviating from the encryption key when the original data are not present in a predetermined relation to the decrypted data; and a second encrypter for encrypting the decrypted data using the encryption algorithm and the auxiliary key in order to obtain output data.