EP1099323A1 - Dispositifs generant des codes de chiffrement et de dechiffrement - Google Patents

Dispositifs generant des codes de chiffrement et de dechiffrement

Info

Publication number
EP1099323A1
EP1099323A1 EP99928133A EP99928133A EP1099323A1 EP 1099323 A1 EP1099323 A1 EP 1099323A1 EP 99928133 A EP99928133 A EP 99928133A EP 99928133 A EP99928133 A EP 99928133A EP 1099323 A1 EP1099323 A1 EP 1099323A1
Authority
EP
European Patent Office
Prior art keywords
characters
primitives
session key
results
encrypt
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP99928133A
Other languages
German (de)
English (en)
Inventor
William Mcmullan Hawthorne
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Chantilley Corp Ltd
Original Assignee
Chantilley Corp Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Chantilley Corp Ltd filed Critical Chantilley Corp Ltd
Publication of EP1099323A1 publication Critical patent/EP1099323A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
    • H04L9/08—Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords
    • H04L9/088—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

Definitions

  • the present invention relates to apparatus arranged to encrypt messages or decrypt messages, particularly to communications apparatus arranged to encrypt messages prior to transmission and decrypt received messages. It is known to provide communications apparatus (for example facsimile machines) with the ability to encrypt messages prior to transmission and decrypt received messages. However, each such apparatus operates with a cypher of a predetermined, fixed cryptographic strength: two apparatus can only communicate with each other if they both use cyphers of the same strength. There are many circumstances in which this limits the ability for communications to be established.
  • an apparatus which is arranged to encrypt or decrypt messages, the apparatus being arranged to generate a session key of a variable selected number of characters and to distribute the characters of said session key in sequence into a predetermined number of groups to form a corresponding predetermined number of primitives, and further arranged to use said primitives, in accordance with a predetermined algorithm, to form a cypher key stream the characters of which are used in sequence to encrypt or decrypt successive characters (or other elements) of a message.
  • the length (i.e. the number of characters) of the session key can be selected: the longer the session key, the greater will be the strength of the cypher.
  • the session key is preferably randomly generated.
  • the characters (typically numerical characters) of the session key are distributed into the predetermined number of groups in a manner forming a corresponding set of multi-digit numbers.
  • the first term allocated to each group may form the first digit of a multi-digit number
  • the second term allocated to that group forms the second digit of the multi-digit number
  • these multi-digit numbers are processed further in order to produce the corresponding set of primitives, used to form the cypher key stream.
  • predetermined values are then added to the respective results of the XOR process, to form a corresponding set of primitives.
  • different values are added to the different results of the XOR process: preferably these different values are different multiples of a basic value. For example, 100 may be added to the first XOR result, 200 to the second, and so on.
  • FIGURE 1 is a schematic block diagram showing part of the electronic system of communications apparatus in accordance with the present invention.
  • FIGURE 2 is a table showing the formation of six different groups of primitives from six session keys of different lengths.
  • a communications apparatus e.g. a facsimile machine
  • means 10 for encrypting a plain message M prior to transmission via a port 12.
  • the microprocessor 10 is provided with a program memory 14 which stores an encryption algorithm and also an algorithm for forming a group of primitives from a session key.
  • the microprocessor is able to generate a session key on a random basis, of selected length.
  • the microprocessor is also arranged to correspondingly decrypt messages received via the port 12.
  • Figure 2 shows six different examples, in which session keys of 56,48,40,32,18 and 12 decimal digits (186,159,133,106,60 and 40 binary bits) are generated.
  • the microprocessor distributes its digits, one- af er-another , into 14 groups, in the same manner as dealing a pack of cards out to the players of a card game.
  • the first 14 digits (44490925319354) form the first digits of respective 4-digit numbers: continuing, the next 14 digits of the session key (89500321347811) form the second digits of the respective 4- digit numbers, the next 14 digits of the session key (67111248217917) form the third digits of the respective 4- digit numbers and the final 14 digits of the session key (36922366044359) form the fourth (and final) digits of the respective 4-digit numbers.
  • the microprocessor 10 combines successive pairs of the 14 numbers in an XOR (exclusive OR) procedure: in each of the examples shown in Figure 2, the second line gives the corresponding results.
  • each number in the first line is combined with the XOR result of the proceeding number, in a process which involves an XOR function or their binary equivalents.
  • the microprocessor 10 adds a multiple of 100 to each of the 14 results formed by the XOR procedure.
  • 100 is added: to the second result, 200 is added; to the third result, 300 is added, and so on up to the seventh result, to which 700 is added.
  • 100 is added: to the ninth result, 200 is added, and so on up to the fourteenth result, to which 700 is added.
  • the final results (last line in each of the 6 examples set out in Figure 2) provide a set of 14 primitives.
  • the 14 primitives thus produced are used by the microprocessor, in accordance with the encryption algorithm, to form a cypher key stream comprising a long stream of digits. Then, in order to encrypt a plain message, the digits of this stream are taken one-after-another, and used in accordance with an encryption algorithm to encrypt respective, successive elements (e.g. characters or groups of characters) of the message to be transmitted. Similarly, in order to decrypt a received message, the digits of the cypher key stream are taken one-after-another and used, in accordance with a decryption algorithm (being the inverse of the encryption algorithm) to decrypt respective, successive elements of the received message.
  • a decryption algorithm being the inverse of the encryption algorithm

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Facsimile Transmission Control (AREA)
  • Storage Device Security (AREA)

Abstract

Dispositif de chiffrement et de déchiffrement de messages conçu pour générer un code de session comportant un nombre variable sélectionné de caractères et pour distribuer ces caractères à la suite en un nombre prédéterminé de groupes afin de constituer un nombre correspondant de primitives. On utilise ces primitives, en fonction d'un algorithme prédéterminé, afin de créer un flot de codes chiffrés dont on met en application les caractères afin de chiffrer ou de déchiffrer des caractères ou des éléments successifs d'un message.
EP99928133A 1998-06-30 1999-06-30 Dispositifs generant des codes de chiffrement et de dechiffrement Withdrawn EP1099323A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GB9814003A GB2339121B (en) 1998-06-30 1998-06-30 Encryption and decryption key arrangements
GB9814003 1998-06-30
PCT/GB1999/002052 WO2000001110A1 (fr) 1998-06-30 1999-06-30 Dispositifs generant des codes de chiffrement et de dechiffrement

Publications (1)

Publication Number Publication Date
EP1099323A1 true EP1099323A1 (fr) 2001-05-16

Family

ID=10834577

Family Applications (1)

Application Number Title Priority Date Filing Date
EP99928133A Withdrawn EP1099323A1 (fr) 1998-06-30 1999-06-30 Dispositifs generant des codes de chiffrement et de dechiffrement

Country Status (4)

Country Link
EP (1) EP1099323A1 (fr)
JP (1) JP2002519940A (fr)
GB (1) GB2339121B (fr)
WO (1) WO2000001110A1 (fr)

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09502845A (ja) * 1993-09-14 1997-03-18 チャンティレイ・コーポレイション・リミテッド 暗号化システムにおけるキー分配装置
US5425103A (en) * 1994-03-14 1995-06-13 Shaw; William Y. Variable-key cryptography system
DE19581586T1 (de) * 1994-03-23 1997-05-28 Chantilley Corp Ltd Vorrichtung zur Erzeugung von Verschlüsselungs/Entschlüsselungs-Nachschlagetabellen unter Verwendung eines Sessionsschlüssels
US5594795A (en) * 1994-07-05 1997-01-14 Ericsson Inc. Method and apparatus for key transforms to discriminate between different networks
JP3294739B2 (ja) * 1995-03-30 2002-06-24 三洋電機株式会社 Ｆｍ多重放送のスクランブルまたはデスクランブル方法
US5828753A (en) * 1996-10-25 1998-10-27 Intel Corporation Circuit and method for ensuring interconnect security within a multi-chip integrated circuit package

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO0001110A1 *

Also Published As

Publication number Publication date
GB9814003D0 (en) 1998-08-26
JP2002519940A (ja) 2002-07-02
GB2339121A (en) 2000-01-12
GB2339121B (en) 2003-03-05
WO2000001110A1 (fr) 2000-01-06

Similar Documents

Publication Publication Date Title
US5222139A (en) Cryptographic method and apparatus
US5351299A (en) Apparatus and method for data encryption with block selection keys and data encryption keys
US5623549A (en) Cipher mechanisms with fencing and balanced block mixing
US7254232B2 (en) Method and system for selecting encryption keys from a plurality of encryption keys
AU611653B2 (en) Enciphering/deciphering method and arrangement for performing the method
AU706247B2 (en) Cryptographic system with concealed work factor
KR19990087103A (ko) 암호키 공유방법
US6640303B1 (en) System and method for encryption using transparent keys
Gautam et al. An enhanced cipher technique using vigenere and modified caesar cipher
US20020159588A1 (en) Cryptography with unconditional security for the internet, commercial intranets, and data storage
WO2002041566A2 (fr) Combineur cryptographique utilisant deux operations sequentielles non associatives
CN109344627B (zh) 一种新型香农完美保密方法
Bhat et al. A novel approach to information security using four dimensional (4d) playfair cipher fused with linear feedback shift register
US7184546B2 (en) Method based on an algorithm capable of being graphically implemented to be used for the generation of filtering of data sequences and crytographic applications
Kwan The design of the ICE encryption algorithm
WO2001091368A2 (fr) Systeme de cryptage base sur des quasigroupes inverses croises
WO2000001110A1 (fr) Dispositifs generant des codes de chiffrement et de dechiffrement
Chunguang et al. Permutation of image encryption system based on block cipher and stream cipher encryption algorithm
Kresmer et al. CCM-SIV: Single-PRF Nonce-Misuse-Resistant Authenticated Encryption
US20200351079A1 (en) Computer-implemented method of replacing a data string
JPH10303881A (ja) 暗号化復号化装置および方法
Khorsheed A Compartive Study Between (AES) and (DES) Algorithms Based on the (SET) Protocol
Rubin The cryptographic uses of post tag systems
Hattab et al. Developing the Complexity and Security of the Twofish Algorithm Through a New Key Scheduling Design
Mandal et al. New Key Generation Technique in RSA Algorithm

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20001208

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE ES FR GB IT

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20040103