Patent EP0366288A2 successfully refreshed from Google Patents.
EP0366288A2
Expired / Lapsed
EP
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Buffered cyphering
Assignee: International Business Machines Corp
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Filing: 1989-10-04
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Granted: —
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Expires: 2009-10-04
Abstract
Abstract Encryption and decryption mechanisms at transmitters and receivers, respectively, have applied thereto encryption or decryption keys and initialising values. These mechanisms generate cryptographic bit streams which are intermediate streams of generated values. These intermediate streams, generated prior to their real time need in the encryption or decryption processes, are stored in buffers until data is presented for encryption or decryption, at which time the cryptographic bit streams are conveyed from the buffers to mathematical functions, for combination with the data. This avoids the delays associated with the real time generation of the cryptographic bit streams during the encryption and decryption processes. Appropriate synchronisation of the generation and buffer storage of the cryptographic bit streams at the transmitter and receiver is provided.
Inventors
- 👤 Todd Allen Smith
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 12:51
CPC Classifications
H; H04; H04L; H04L9/00; H04L9/06; H04L9/065
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
70 words
A method for ciphering - encrypting and/or decrypting - data in a data processing system, comprising: generating a cryptographic bit stream, in advance of and thus independently of receipt of data to be ciphered; buffering the cryptographic bit stream upon its generation; and retrieving the cryptographic bit stream, or sufficient thereof, form the buffer and combining it with the data to be ciphered using it, as that data is received.
Claim 2
Independent Claim
70 words
A method for ciphering - encrypting and/or decrypting - data in a data processing system, comprising: generating a cryptographic bit stream, in advance of and thus independently of receipt of data to be ciphered; buffering the cryptographic bit stream upon its generation; and retrieving the cryptographic bit stream, or sufficient thereof, form the buffer and combining it with the data to be ciphered using it, as that data is received.
Claim 3
Dependent Claim
40 words
A method as claimed in claim 1, wherein the buffer is loaded with the cryptographic bit stream upon generation, control of the buffer being locked during the loading, to prevent the removal of the cryptographic bit stream during the loading.
Claim 4
Independent Claim
34 words
A method as claimed in either preceding claim, wherein control of the buffer during retrieval of the cryptographic bit stream is locked, to prevent the loading of the cryptographic bit stream during its retrieval.
Claim 5
Independent Claim
38 words
A method as claimed in claims 2 and 3, wherein locking of the buffer is accomplished by suspending the potential user - to promote loading of the buffer, unless full, for encription, and decyphering, unless empty, at reception.
Claim 6
Dependent Claim
40 words
Amethod as claimed in any preceding claim, wherein a number of bits of the data to be ciphered are combined with a number of bits of the cryptographic bit stream according to a mathematical function, such as an EXCLUSIVE-OR function.
Claim 7
Dependent Claim
75 words
Ciphering apparatus adapted to perform the method as claimed in any preceding claim, comprising: logic for generating a cryptographic bit stream, in advance of and thus independently of receipt of data to be ciphered; a memory for buffering the cryptographic bit stream upon its generation; and logic for retrieving the cryptographic bit stream, or sufficient thereof, form the buffer and combining it with the data to be ciphered using it, as that data is received.
Claim 8
Dependent Claim
54 words
Apparatus as claimed in claim 6, wherein the buffer is loaded with the cryptographic bit stream upon generation, control means being provided to lock the buffer, directly or indirectly, to prevent the removal of the cryptographic bit stream during the loading, and to prevent the loading of the cryptographic bit stream during its retrieval.
Claim 9
Dependent Claim
41 words
Apparatus as claimed in claim 6 or claim 7, wherein the retrieving and combining logic combines a number of bits of the data to be ciphered with a number of bits of the cryptographic bit stream according to a mathematical function.
Claim 10
Dependent Claim
14 words
Apparatus as claimed in claim 8, wherein the mathematical function is an EXCLUSIVE-OR function.
Claim 11
Dependent Claim
132 words
A data processing system method for enciphering plaintext to be communicated into ciphertext and deciphering the ciphertext into the plaintext after communication, comprising: generating, timewise independent of receipt before communication of the plaintext, a first cryptographic bit stream; buffering the first cryptographic bit stream upon its generation; combining, after the buffering and timewise independent of the generating the first cryptographic bit stream, the first cryptographic bit stream with the plaintext to be communicated to generate the ciphertext; generating, timewise independent of receipt of the ciphertext, a second cryptographic bit stream; buffering the second cryptographic bit stream upon its generation; and combining, after the buffering and timewise independent of the generating the second cryptographic bit stream, the second cryptographic bit stream with the ciphertext to regenerate the plaintext after receipt of the ciphertext.
Claim 12
Dependent Claim
132 words
A data processing system method for enciphering plaintext to be communicated into ciphertext and deciphering the ciphertext into the plaintext after communication, comprising: generating, timewise independent of receipt before communication of the plaintext, a first cryptographic bit stream; buffering the first cryptographic bit stream upon its generation; combining, after the buffering and timewise independent of the generating the first cryptographic bit stream, the first cryptographic bit stream with the plaintext to be communicated to generate the ciphertext; generating, timewise independent of receipt of the ciphertext, a second cryptographic bit stream; buffering the second cryptographic bit stream upon its generation; and combining, after the buffering and timewise independent of the generating the second cryptographic bit stream, the second cryptographic bit stream with the ciphertext to regenerate the plaintext after receipt of the ciphertext.
References Cited (Backward Citations)
No citation records indexed.
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