STEP CODE CIPHERING SYSTEM
First Claim
1. A process for multiple level encipherment of a data block consisting of binary digits said process comprising the steps of:
- arranging a stream of binary digit data into a plurality of data segments;
loading one data segment from said plurality of data segments into a cryptographic block ciphering device for first generating a block cipher;
following the first generation of a block cipher, retaining a portion of said block cipher and combining it with another data segment to form a composite data block;
loading said composite data block into a cryptographic block ciphering device for generating a composite block cipher;
sequentially generating composite block ciphers from said data segments until said data stream is exhausted.
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Abstract
This specification discloses a system that provides multiple level encipherment of a block of data by means of a stepped block cipher process. A data stream consisting of digital information is segmented into blocks of dimension D, each block is enciphered by means of a block cipher cryptographic system operating under the control of a unique subscriber digital key. The cryptographic system develops a first cipher text of equal dimension as the block D. Then the cryptographic system is effectively shifted to accept a plurality of data bits from a second data block and a plurality of bits from the first cipher. The combination of block data bits and ciphertext data bits forms a composite block of dimension equal to the data block D. This combination is introduced to the cryptographic device for developing a second cipher text. The combined output of the second ciphertext and those information symbols from the first ciphertext which were not reintroduced to the cryptographic device are transmitted as a complete unit to a receiving station which will decipher the received multiple level cryptogram by an inverse process. The multiple level encipherment process is also utilized in a variant key embodiment which would encipher a data block D into a cipher C which is a function of a key control block consisting of a random combination binary digits that are continuously changing. In a further embodiment which utilizes multiple level encipherment, there is presented a method for providing secrecy in communications between a central processing unit and its data banks.
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Citations
7 Claims
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1. A process for multiple level encipherment of a data block consisting of binary digits said process comprising the steps of:
- arranging a stream of binary digit data into a plurality of data segments;
loading one data segment from said plurality of data segments into a cryptographic block ciphering device for first generating a block cipher;
following the first generation of a block cipher, retaining a portion of said block cipher and combining it with another data segment to form a composite data block;
loading said composite data block into a cryptographic block ciphering device for generating a composite block cipher;
sequentially generating composite block ciphers from said data segments until said data stream is exhausted.
- arranging a stream of binary digit data into a plurality of data segments;
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2. The process as defined in claim 1 wherein said cryptographic system develops a block cipher under the control of a combination of binary digits obtained from a unique key code associated with a particular individual.
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3. The process as defined in claim 2 wherein said combination of binary digits comprises:
- a block of binary digits whose combination at any particular time is a random arrangement of one'"'"''"'"'s and zero'"'"''"'"'s.
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4. The process as defined in claim 3 wherein pairs of ciphers are generated under alternate control of a subscriber key and a random combination of binary digits.
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5. The process as defined in claim 4 further comprising:
- combining said random combination of binary digits with portions of data segments for generating composite ciphers.
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6. A process for multiple level encipherment and decipherment of a stream binary data digits comprising the steps of:
- segmenting said data stream into a plurality of blocks each n digits in dimension;
loading at least one of said blocks of n-digits into a cryptographic device for developing a first block cipher;
storing a portion of said first block cipher into a storage means;
loading further ones of said blocks of n-digits into said cryptographic device to be combined with the remaining portiOn of said first block cipher;
forming a second block cipher from the combination of a further block and said remaining portion of said first block cipher;
combining said first and second block ciphers into a composite block cipher in said storage means prior to transmission;
transmitting said composite block cipher;
receiving said composite block cipher at a receiving station and deciphering it by an inverse operation of said cryptographic device.
- segmenting said data stream into a plurality of blocks each n digits in dimension;
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7. The system as defined in claim 6 wherein said block ciphers generated by said cryptographic device are alternately functions of a combination of binary digits associated with a particular subscriber to a computing network and a random combination of binary digit representations.
Specification