Encryption system

• US 4,853,962 A
• Filed: 12/07/1987
• Issued: 08/01/1989
• Est. Priority Date: 12/07/1987
• Status: Expired due to Fees

• Current Assignee: UC Consulting Incorporated
• Original Assignee: Universal Computer Consulting Incorporated
• Inventors: Brockman, Robert T.
• Primary Examiner(s): Buczinski, Stephen C.
• Application Number:
  US07/129,306
• Time in Patent Office: 603 Days
• Field of Search: 380/21, 380/23, 380/25, 380/28, 380/44, 380/45, 380/47
• US Class Current: 380/44
• CPC Class Codes: H04L 9/3236 using cryptographic hash functions

Abstract

A method for encrypting signals utilizes the receiver serial number to generate an index number which is used in turn to select an encryption table from among a plurality of such tables. The index number used in conjuction with any given signal is modified for greater security by adding the units digit of the signal length. Further modification of the index number can be made by adding the units digit of the time of transmission. The index number is further modified by adding a shift number by which all data characters are shifted during encryption. In signals based on a defined protocol, the shift number and the units digit of the transmission time are hidden in unused protocol positions within the signal.

Claims

1. A method for encrypting a signal for transmission to a receiver,

said signal having a known length representable by a length number comprising one or more digits,

said receiver having a known identifying number comprising one or more digits,

the method comprising the steps of:

generating a hash number by performing a specified hashing operation using the identifying number as an operand;

generating a single-digit index number by adding the units digit of the signal length number to the hash number and performing a specified generation operation; and

encrypting the signal in accordance with an encryption table corresponding to said index number.

10. An information storage device tangibly embodying a program comprising instructions adaptable for execution on a programmed machine,

wherein the method of any one of claims 1-9 is performable through the execution of said instructions by the machine.

2. A method for encrypting a signal for transmission to a receiver, said receiver having a known identifying number comprising one or more digits, said method comprising the steps of:

generating a hash number by performing a specified hashing operation using the identifying number as an operand;

encoding an arbitrary number at a specified position in the signal outside the specified portion;

generating a single-digit index number by adding the arbitrary number to the hash number and performing a specified generation operation; and

encrypting the signal in accordance with an encryption table corresponding to said arbitrary number.

3. A method for encrypting a signal for transmission to a receiver

said signal having a known length representable by a length number comprising one or more digits,

said receiver having a known identifying number comprising one or more digits,

the method comprising the steps of:

generating a hash number by performing a specified hashing operation using the identifying number as an operand;

generating a single-digit index number by adding the units digit of the signal length number to the hash number and performing a specified generation operation; and

encrypting the signal in accordance with an encryption table corresponding to said index number.

4. A method for encrypting a specified portion of a signal for transmission to a receiver,

said specified portion having a known length representable by a length number comprising one or more digits,

said receiver having a known identifying number comprising one or more digits,

the method comprising the steps of:

performing a summing-of-the-digits operation on said identifying number to generate a single-digit hash number;

encoding an arbitrary single-digit number at a specified position in the signal outside the specified portion;

obtaining an index number by adding to the hash number (a) the units digit of the signal length number and (b) the arbitrary single-digit number, and if the result is greater than the base of the numbering system in which the index number is expressed, subtracting said base; and

encrypting the signal in accordance with an encryption table corresponding to said index number.

5. A method for encrypting a specified portion of a signal for transmission to a controller for retransmission to a receiver,

said specified portion having a known length representable by a signal length number,

said controller and said receiver each having a known identifying number comprising one or more digits,

the method comprising the steps of:

performing a specified hashing operation on the controller identifying number to generate a controller hash number;

encoding an arbitrary number at a specified position in the signal outside the specified portion;

generating an index number by adding to the controller hash number (a) said signal length number and (b) the arbitrary number;

performing a specified hashing operation on the receiver identifying number to generate a shift number;

adding the shift number to selected numeric representations of data symbols within the signal; and

generating an encrypted signal in accordance with an encryption table corresponding to said index number.

6. A method for encrypting a specified portion of a signal for transmission to a controller for retransmission to a receiver,

said specified portion having a known length representable by a length number comprising one or more digits,

said controller and said receiver each having a known identifying number comprising one or more digits,

the method comprising the steps of:

performing a summing-of-the-digits operation on the receiver identifying number to generate a single-digit shift number;

generating a shifted signal by adding the shift number to selected numeric representations of data symbols within the signal;

performing a summing-of-the-digits operation on the controller identifying number to generate a single-digit controller sum number;

encoding the units digit of a representation of the present time at a specified position in the signal outside the specified portion;

obtaining a single-digit index number by adding to the controller sum number (a) the units digit of the signal length number and (b) the arbitrary single digit number and, if the result is greater than the base of the numbering system in which the result is expressed, subtracting said base;

generating an encrypted signal based on the shifted signal using an encryption table corresponding to said index number.

7. A method for using a plurality of numbered encryption tables to encrypt a signal for transmission to a receiver,

said receiver having a known identifying number,

said signal having a known length,

the method comprising the steps of:

generating an index number by performing one or more specified generation operations using the identifying number and the signal length as operands; and

encrypting the signal in accordance with an encryption table corresponding to said index number.

8. A method for using a plurality of numbered encryption tables to encrypt a specified portion of a signal for transmission to a receiver,

said receiver having a known identifying number,

said signal having a known length,

the method comprising the steps of:

encoding an arbitrary number into the signal at a position outside the specified portion;

generating an index number by performing one or more specified generation operations using the identifying number, the arbitrary number, and the signal length as operands; and

encrypting the signal in accordance with the encryption table corresponding to said index number.

9. A method for using a plurality of numbered encryption tables to encrypt a specified portion of a signal for transmission to a controller for retransmission to a terminal,

said control and said terminal each having a known identifying number,

said signal having a known length,

the method comprising the steps of:

encoding an arbitrary number into the signal at a position outside the specified portion;

generating an index number by performing one or more specified generation operations using the controller identifying number, the terminal identifying number, the arbitrary number, and the signal length as operands; and

encrypting the signal in accordance with the encryption table corresponding to said index number.