1、BRITISH STANDARD BS ISO 10126-1:1991 Implementation of ISO 10126-1:1991 Banking Procedures for message encipherment (wholesale) Part 1: General principles UDC 336.719.2:355.405.2:681.3.04BSISO10126-1:1991 This British Standard, having been prepared under the directionof the Information Systems Techn
2、ology StandardsPolicy Committee, waspublishedunder the authorityofthe Standards Boardand comes intoeffecton 31January1992 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference IST/12 Draft for comment 89/63555 DC ISBN 0 580 20452 9 Committees responsible f
3、or this British Standard The preparation of this British Standard was entrusted by the Information Systems Technology Standards Policy Committee (IST/-) to Technical Committee IST/12, upon which the following bodies were represented: American Banks and Securities Association of London Association fo
4、r Payment Clearing Services Building Societies Association British Telecommunications plc IBM (UK) Ltd. The London Stock Exchange The following bodies were also represented in the drafting of the standard, through subcommittees and panels: British Bankers Association Institutional Fund Managers Asso
5、ciation Securities and Investments Board Stock Exchange Management Association The EDI Association The London Stock Exchange Amendments issued since publication Amd. No. Date CommentsBSISO10126-1:1991 BSI 10-1999 i Contents Page Committees responsible Inside front cover National foreword ii Foreword
6、 iii Text of ISO 10126-1 1BSISO10126-1:1991 ii BSI 10-1999 National foreword This British Standard reproduces verbatim ISO 10126-1:1991 and implements it as the UK national standard. This British Standard is published under the direction of the Information Systems Technology Standards Policy Committ
7、ee whose Technical Committee IST/12 has the responsibility to: aid enquirers to understand the text; present to the responsible international committee any enquiries on interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments an
8、d promulgate them in the UK. NOTEInternational and European Standards, as well as overseas standards, are available from BSI Sales Department, BSI, Linford Wood, Milton Keynes, MK14 6LE. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Stand
9、ards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the ISO title page, pages ii to iv, pages 1 to 14 and a bac
10、k cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.ISO10126-1:1991(E) ii BSI 10-1999 Contents Page Foreword iii Introduction 1 1 Scope 1 2 Normative references 1 3 Definitions
11、1 4 Application 2 5 Encipherment and decipherment of entire messages and encipherment elements 3 6 Transparent transmission of enciphered data 5 7 Order of processing 8 8 Approval procedure for encipherment algorithms 8 Annex A (normative) Procedure for review of alternative encipherment algorithms
12、9 Annex B (informative) Examples of filtering 10 Annex C (informative) Filtering Expansion factors for selected filters 12 Annex D (informative) Examples illustrating the encipherment and decipherment of encipherment elements 13 Figure 1 Filter padding field format 7 Figure 2 Message flow 8 Table 1
13、ISO 646 filter 5 Table 2 ISO 646/baudot filter 6 Table 3 ISO 646/baudot filter 7 Table 4 Filter padding 7 Table C.1 Expansion factors 12 Descriptors: Banking, messages, protection of information, coded representation.ISO10126-1:1991(E) BSI 10-1999 iii Foreword ISO (the International Organization for
14、 Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the
15、right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft Inte
16、rnational Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least75% of the member bodies casting a vote. International Standard ISO10126-1was prepared by Technical Committee ISO/TC68, Bankin
17、g and related financial services, Sub-Committee SC 2, Operations and procedures. ISO10126consists of the following parts, under the general title Banking Procedures for message encipherment (wholesale): Part 1: General principles; Part 2: DEA algorithm. ISO10126originates from work done in ANSI, and
18、 is a development of (whileremaining compatible with) ANSI X9.23 (1988), Financial Institution: Encryption of Wholesale Financial Messages. The four annexes to this parts of ISO10126are intended to simplify its implementation. a) Annex A provides the procedure for review of alternative encipherment
19、algorithms. b) Annex B provides examples of the various filtering techniques described in this part of ISO 10126. c) Annex C provides a comparison of the effects of the filters described in this part of ISO10126and, by use of the expansion factor, shows the relationship between the number of bits tr
20、ansmitted and those originated. d) Annex D provides examples of the three methods for encipherment and decipherment of encipherment elements within a message which are described in this part of ISO 10126. Annex A forms an integral part of this part of ISO 10126. Annex B, Annex C and Annex D are for
21、information only.iv blankISO10126-1:1991(E) BSI 10-1999 1 Introduction This part of ISO10126specifies a method for the encipherment and decipherment of entire (or parts of) wholesale financial messages by the use of application level encipherment, for the purpose of providing confidentiality. The le
22、vel of security provided by this part of ISO10126is dependent upon a) the security associated with the algorithm used for encipherment and the implementation of that algorithm within the procedures laid down by this part of ISO10126and, b) the operation of a secure system of key management. Particul
23、ar algorithms, suitable for use with this part of ISO 10126, are described in ISO 10126-2. A suitable International Standard for key management is described in ISO 8732. 1 Scope The procedures defined are designed to protect, by means of encipherment, financial messages (entire messages or encipherm
24、ent elements) exchanged through any communications architecture. Such architectures will include store and forward and telex environments, any number of nodes and public or private networks. Since enciphered text can interfere with communications processes in existing wholesale financial networks, t
25、his part of ISO10126provides a means to permit the enciphered message to be transmitted through a number of networks without being misinterpreted as communications protocol information e.g. STX (start of text), EOT (end of text). The confidentiality of financial message data, in both structured and
26、unstructured forms, is protected by the use of this part of ISO 10126. The techniques described do not provide integrity protection (i.e. protection against modification, substitution and replay). Data integrity protection is the subject of ISO8730and ISO 8731. Message formats are also beyond the sc
27、ope of this part of ISO 10126. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part of ISO 10126. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties t
28、o agreements based on this part of ISO10126are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 646:1983, Information processing ISO 7-bit coded c
29、haracter set for information interchange. ISO 8730:1990, Banking Requirements for message authentication (wholesale). ISO 8731-1:1987, Banking Approved algorithms for message authentication Part 1: DEA. ISO 8731-2:1987, Banking Approved algorithm for message authentication Part 2: Message authentica
30、tor algorithms. ISO 8732:1988, Banking Key management (wholesale). ISO 10126-2:1991, Banking Procedures for message encipherment (wholesale) Part 2: DEA algorithms. 3 Definitions For the purposes of this part of ISO 10126, the following definitions apply. 3.1 baudot a five bit character information
31、coding scheme (excluding optional start bits and stop bits); CCITT Alphabet Number 2 3.2 block a data unit with a specified length 3.3 ciphertext enciphered information 3.4 communicating pair two logical parties who have previously agreed to exchange data 3.5 cryptographic key; key a parameter used
32、in conjunction with an algorithm for the purpose of encipherment or decipherment 3.6 data unit binary vector of K bits denoted as (B1, B2, ., BK) 3.7 decipherment the reversal of a corresponding reversible encipherment 3.8 enciphered element enciphered encipherment elementISO10126-1:1991(E) 2 BSI 10
33、-1999 3.9 encipherment the cryptographic transformation of data to produce ciphertext 3.10 encipherment element a contiguous group of plaintext characters which is to be enciphered 3.11 filtering the process of encoding binary text into a format insensitive to control characters 3.12 financial messa
34、ge a communication containing information which has financial implications 3.13 initialization vector (IV) a number used as a starting point for encipherment of a data sequence. It increases security by introducing additional cryptographic variance, and also facilitates the synchronization of crypto
35、graphic equipment 3.14 initial text sequence (ITS) an n-bit binary vector which may be prefixed to a message 3.15 key see cryptographic key 3.16 logical party one or more physical parties forming one member of a communicating pair 3.17 message a communication containing one or more transactions or r
36、elated information 3.18 most significant bit(s) the leftmost bit(s) of a binary vector 3.19 octet a group of eight binary digits numbered from left to right: B1, B2, ., B8 3.20 padding one or more bits appended to a message in order to cause the message to contain an exact multiple of the number of
37、bits required by the filtering process or the cryptographic algorithm 3.21 plaintext unenciphered information 3.22 receiver the logical party that is authorized to decipher a received message 3.23 sender the logical party that is responsible for originating an enciphered message 4 Application 4.1 Pr
38、otection provided The confidentiality of financial message data is protected by the use of this part of ISO10126. This part of ISO10126 provides a method of protection for both structured and unstructured message data. Confidentiality protection is provided between two logical parties. The logical p
39、arties to a communication are the sender and receiver. 4.2 General operation 4.2.1 Processing The sender of a financial message shall generate ciphertext by applying the encipherment process described in clause 5 either to the entire plaintext message, or to encipherment elements within the message,
40、 using a secure system of key management. The message is then forwarded to the receiver. The receiver shall decipher the ciphertext by applying the decipherment procedures described in clause 5. Note that the cryptographic process is sensitive to the sequence in which the plaintext is enciphered, an
41、d that sequence must be the same at the time of encipherment and decipherment. If decipherment of an entire message or encipherment elements is required at a later date, an audit journal shall include sufficient information to retrieve the key, the message and any other information used in the crypt
42、ographic process. When a financial message is both authenticated and enciphered, the message shall be authenticated prior to encipherment, and different keys shall be used for encipherment and authentication.ISO10126-1:1991(E) BSI 10-1999 3 4.2.2 Communications methods This part of ISO10126may be us
43、ed to encipher entire financial messages or encipherment elements within messages transmitted over any communications media through any number of nodes in public or private networks. 5 Encipherment and decipherment of entire messages and encipherment elements 5.1 General Entire messages and encipher
44、ment elements shall be enciphered and deciphered in accordance with ISO 10126-2. There are four methods of encipherment allowed by this part of ISO 10126, i.e. entire message encipherment and three methods for enciphering encipherment elements. Several messages using different keys, different modes
45、of operation, or methods of encipherment (see 5.3) and filters (see clause 6) may be combined within a single transmission. 5.2 Encipherment and decipherment of entire messages When an entire message is to be enciphered, all plaintext other than header and trailer information (e.g. information added
46、 by a network for transmission purposes) shall be enciphered. The Initial Text Sequence (if present), the entire message including the MAC (if present), and the padding field (if present) shall be enciphered as a unit. After encipherment, ciphertext may be filtered in accordance with clause 6. When
47、an entire message is to be deciphered, all ciphertext is deciphered as a unit. 5.3 Encipherment and decipherment of encipherment elements Three methods for encipherment and decipherment of encipherment elements within a message are permitted by this part of ISO 10126. Method 1: Encipherment elements
48、 are independently enciphered into enciphered elements. Enciphered elements are independently deciphered into encipherment elements (see 5.3.2). Method 2: Encipherment elements are concatenated and enciphered as a single data string. The resulting ciphertext string is transmitted in the message as a
49、 single string. The ciphertext string is deciphered and the encipherment elements are inserted into the message text (see 5.3.3.1). Method 3: Encipherment elements are concatenated and enciphered as a single data string. The resulting ciphertext string is divided into ciphertext substrings for transmission in the message. The ciphertext substrings are concatenated and deciphered as a single string. The resulting encipherment elements are inserted into the message text (see 5.3.3.2). After encipherment, ciphertext may be filt
