Data encrypting and decrypting apparatus and method

• US 6,490,353 B1
• Filed: 11/23/1998
• Issued: 12/03/2002
• Est. Priority Date: 11/23/1998
• Status: Expired due to Fees

• Current Assignee: Tan, Daniel Tiong Ho{umlaut over (k)}
• Original Assignee: Tan, Daniel Tiong Ho{umlaut over (k)}
• Inventors: Tan, Daniel Tiong Ho{umlaut over (k)}
• Primary Examiner(s): Peeso, Thomas R.
• Application Number:
  US09/198,238
• Time in Patent Office: 1,471 Days
• Field of Search: 380/37, 380/278, 380/281, 380/283, 380/44
• US Class Current: 380/37
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 9/088 Usage controlling of secret information, e.g. techniques for restricting cryptographic keys to pre-authorized uses, different access levels, validity of crypto-period, different key- or password length, or different strong and weak cryptographic algorithms network architectures or network communication protocols for using time-dependent keys in a packet data network H04L63/068
• CPC Class Codes: H04L 9/16 the keys or algorithms being changed during operation

Abstract

A crytography method of encrypting data is disclosed. The method provides for creating or selecting a master key. Thereafter, the data to be encrypted is segmented into data blocks of equal or variable lengths. For each data block a sub-key of an arbitrary starting position is selected from a pre-defined set of arbitrary positions and of matched or unmatched length from the master key, where the master key length is selected from a pre-defined set of arbitrary lengths. Having acquired the sub-key for each data block, each data block is encrypted using its sub-key and an encryption algorithm.

Claims

1. A method of encrypting data including the following steps:

(a) creating or selecting a master key;

(b) segmenting the data into data blocks of equal or variable lengths;

(c) for each data block selecting a sub-key of arbitrary starting position selected from a pre-defined set of arbitrary positions and of matched or unmatched length from the master key, said length being selected from a pre-defined set of arbitrary lengths; and

(d) encrypting each data block using its sub-key and an encryption algorithm.

2. A method of encrypting data according to claim 1 further including the preliminary step of creating a seed, wherein the seed includes the pre-defined set of arbitrary positions and the pre-defined set of arbitrary lengths.

3. A method of encrypting data according to claim 2 including the further preliminary step of distributing the seed to a message recipient who, upon receiving the encrypted data blocks, is able to decrypt the data using the master key and the seed.

4. A method of encrypting data according to claim 3 wherein the master key and/or the seed are kept secret.

5. A method of encrypting data according to claim 3 wherein the master key and/or seed are selected from one or more binary files.

6. A method of encrypting data according to claim 2 wherein the seed further includes a pre-defined set of encryption algorithms, one of which is selected for encrypting each data block.

7. A method of encrypting data according to claim 1 wherein the data blocks are of arbitrary length.

8. A method of encrypting data according to claim 1 including, before the step of encrypting each data block, the step of selecting for each data block a specific algorithm to be used, together with that data block'"'"'s sub-key, in the step of encrypting that data block.

9. A method of applying a digital signature to an electronic document, including the step of encrypting the document or a part of the document or data appended to the document according to the method of claim 1.

10. A method of encrypting data including the following steps:

(a) creating or selecting a master key;

(b) creating a seed which includes a pre-defined set of suitable algorithms;

(c) segmenting the data into data blocks of equal or variable lengths;

(d) for each data block selecting an encryption algorithm from said pre-defined set of suitable algorithms;

(e) encrypting each data block using its encryption algorithm.

11. A method of encrypting data according to claim 10 including the further preliminary step of distributing the seed to a message recipient who, upon receiving the encrypted data blocks, is able to decrypt the data using the master key and the seed.

12. A method of encrypting data according to claim 11 wherein the master key and/or the seed are kept secret.

13. A method of encrypting data according to claim 11 wherein the master key and/or seed are selected from one or more binary files.

14. A method of encrypting data according to claim 10 wherein the data blocks are of arbitrary length.

15. A method of applying a digital signature to an electronic document, including the step of encrypting the document or a part of the document or data appended to the document according to the method of claim 10.

16. A method of communicating data in a secure manner from a message transmitter to a message receiver including the following steps:

(a) creating a seed which includes a set of arbitrary sub-key start positions, a set of arbitrary sub-key lengths, and a set of suitable encryption algorithms;

(b) communicating the seed to the message receiver over a secured channel;

(c) creating or selecting a master key;

(d) communicating the master key to the message receiver over a secured channel;

(e) dividing the data into data blocks of arbitrary length;

(f) for each data block, selecting from the seed a sub-key start position, a sub-key length, and an encryption algorithm;

(g) using the sub-key start position and length for each data block to derive from the master key a sub-key for that data block;

(h) encrypting each data block using that data block'"'"'s sub-key and encryption algorithm;

(i) transmitting each encrypted data block to the receiver together with a sub-key start position index number, sub-key length index number and encryption algorithm index number for each data block, enabling the receiver to derive the appropriate sub-key and encryption algorithm and thereby to decrypt the data block.

17. A method of communicating data according to claim 16 wherein the seed and the master key are communicated to the receiver over separate secure channels.

18. Apparatus for encrypting data including:

(a) a data block creating processor, which accepts a stream of data as its input, and outputs the data in the form of blocks;

(b) a random selector, which selects a sub-key start position and a sub-key length;

(c) a sub-key selector, which accepts as inputs a master key, the sub-key start position and sub-key length, and derives from these a sub-key;

(d) an encryption processor, which accepts as inputs a sub-key and a data block, and uses the sub-key to encrypt the data block according to an encryption algorithm.

19. Apparatus for encrypting data according to claim 18 wherein the data block creating processor creates d data blocks of random lengths.

20. Apparatus for encrypting data according to claim 18 wherein the random selector also selects an encryption algorithm from a group of suitable algorithms, and the encryption processor accepts the encryption algorithm as one of its inputs.

21. Apparatus for encrypting data according to claim 18 further including a plurality of encryption processors, each embodying an encryption algorithm, wherein the random selector also selects an encryption processor, with the selected encryption processor being the processor which encrypts the data block according to its encryption algorithm.

22. Apparatus for communicating data in a secure manner from a message transmitter to a message receiver, including:

(a) a data block creating processor, which accepts a stream of data as its input, and outputs the data in the form of blocks;

(b) a random selector, which selects a sub-key start position, a sub-key length, and an encryption algorithm;

(c) a sub-key selector, which accepts as inputs a master key, the sub-key start position and sub-key length, and derives from these a sub-key;

(d) an encryption processor, which accepts as inputs a sub-key, an encryption algorithm and a data block, and uses the sub-key to encrypt the data block according to the encryption algorithm; and

(e) apparatus for transmitting each encrypted data block to the receiver together with a sub-key start position index number, sub-key length index number and encryption algorithm index number for each data block, enabling the receiver to derive the appropriate sub-key and encryption algorithm and thereby to decrypt the data block.

23. Apparatus for communicating data in a secure manner from a message transmitter to a message receiver, including:

(a) a data block creating processor, which accepts a stream of data as its input, and outputs the data in the form of blocks;

(b) a plurality of encryption processors, each embodying an encryption algorithm, and each of which accepts as inputs a sub-key and a data block, and uses the sub-key to encrypt the data block according to its algorithm;

(c) a random selector, which selects, for each data block, a sub-key start position, a sub-key length, and an encryption processor;

(d) a sub-key selector, which accepts as inputs a master key, the sub-key start position and sub-key length, and derives from these a sub-key;

apparatus for transmitting each encrypted data block to the receiver together with a sub-key start position index number, sub-key length index number and encryption algorithm index number for each data block, enabling the receiver to derive the appropriate sub-key and encryption algorithm and thereby to decrypt the data block.