Password-based key derivation without changing key

A data securing system, comprising:

• an inputting hardware device for inputting a first personal identification number, a second personal identification number and a third personal identification number, wherein the first personal identification number is different from the third personal identification number;
• a random number generating hardware device for generating a first random number and creating a pseudo-random number by performing an exclusive-OR (XOR) operation on the first personal identification number, the second personal identification number and the first random number;
• a key generating hardware device for creating a first key by performing an exclusive-OR (XOR) operation on the first personal identification number and the first random number and creating a second key by performing an exclusive-OR (XOR) operation on the third personal identification number and the pseudo-random number;
• a crypto hardware device for creating a first secure checksum according to the first key and encrypting a data according to the first key, and further creating a second secure checksum according to the second key;
• and
• a storage hardware device for storing the first random number, part of the first secure checksum and the encrypted data;
• wherein the first random number is replaced by the pseudo-random number, and the crypto hardware device further determines whether part of the second secure checksum is identical to the part of the first secure checksum and decrypts the encrypted data according to the second key if the part of the second secure checksum is identical to the part of the first secure checksum.

A data carrier, for storing and encrypting a data, wherein a first secure checksum is created according to a first key, a second secure checksum is created according to a second key, the data is encrypted according to the first key, and the data carrier comprises:

• a random number generating hardware device for generating a first random number and creating a pseudo-random number by performing an exclusive-OR (XOR) operation on a first personal identification number, a second personal identification number, and the first random number, wherein the first personal identification number is different from a third personal identification number;
• a storage hardware device for storing the first random number, part of the first secure checksum and the encrypted data, and for replacing the first random number with the pseudo-random number;
• a key generating hardware device for creating the first key by performing an exclusive-OR (XOR) operation on the first personal identification number and the first random number and creating the second key by performing an exclusive-OR (XOR) operation on the third personal identification number and the pseudo-random number;
• and
• a crypto hardware device for determining whether part of the second secure checksum is identical to part of the first secure checksum and decrypting the encrypted data according to the second key if the part of the second secure checksum is identical to the part of the first secure checksum.

A non-transitory computer-readable storage device with computer-executable instructions stored thereon that, when executed by one or more computer processors, cause the one or more computer processors to perform procedures comprising:

• an encryption procedure including:
• receiving a first personal identification number by an inputting hardware device;
• generating a first random number by a random number generating hardware device;
• creating a first key by a key generating hardware device by performing an exclusive-OR (XOR) operation on the first personal identification number and the first random number;
• creating a first secure checksum by a crypto hardware device according to the first key;
• storing the first random number and part of the first secure checksum by a storage hardware device;
• and
• encrypting the data by the crypto hardware device with the first key;
• a personal identification number changing procedure including:
• receiving a second personal identification number;
• creating a pseudo-random number by performing an exclusive-OR (XOR) operation on the first personal identification number, the second personal identification number, and the first random number;
• and
• replacing, by the storage hardware device, the stored first random number with the pseudo-random number;
• a decryption procedure including:
• receiving a third personal identification number by the inputting hardware device, wherein the first personal identification number is different from the third personal identification number;
• creating a second key by the key generating hardware device by performing an exclusive-OR (XOR) operation algorithm on the third personal identification number and the pseudo-random number;
• creating a second secure checksum by the crypto hardware device according to the second key;
• determining whether part of the second secure checksum is identical to the part of the first secure checksum;
• and
• decrypting the encrypted data with the second key if the part of the second secure checksum is identical to the part of the first secure checksum.