Cryptography – Electric signal modification – Having production of printed copy
Patent
1987-10-14
1988-07-26
Cangialosi, Salvatore
Cryptography
Electric signal modification
Having production of printed copy
380 44, 380 28, H04L 900
Patent
active
047606002
ABSTRACT:
In a cipher system used in transmission or storage of digital data, the encipherment section comprises a first modulo-2 adder for adding, bit by bit, the k-bit contents of a first shift register storing latest k bits of ciphertext information and the k-bit contents of a first register. The k-bit output of the first modulo-2 adder is expanded into m.times.n bits, which are stored in a second register, and extracted in sequence, a set of n bits at a time. Each set of n bits is converted into a single bit. A second modulo-2 adder adds the 1 bit output to the contents of a third register, which stores the output of the second adder. A fifth register stores plaintext information input through the input terminal. A third modulo-2 adder adds the output of the second adder to the contents of a register storing plain text information to ciphertext information. A sixth register stores the output of the third adder. The contents of the sixth register are fed back to the first shift register, and are also output as ciphertext information.
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Cangialosi Salvatore
Lewis Aaron J.
OKI Electric Industry Co., Ltd.
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