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EP0505302A1
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Authentication protocols in communication networks
Assignee: International Business Machines Corp
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Filing: 1992-02-11
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Granted: —
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Expires: 2012-02-11
Abstract
Abstract A arrangement of authenticating communications network users and means for carrying out the arrangement. A first challenge N1 is transmitted from a first user A to a second user B (300). In response to the first challenge, B generates and transmits a first response to the challenge and second challenge N2 to A. A verifies that the first response is correct. A then generates and transmits a second response to the second challenge to B, where the second response is verified. The first response must be of a minimum form f(S1, N1,...), and the second response must be of the minimum form g(S2, N2,...). S1 and S2 are shared secrets between A and B. S1 may or may not equal to S2, In addition, f() and g() are selected such that the equation f′(S1, N1′,...) = g(S2, N2) cannot be solved for N1′ without knowledge of S1 and S2. f′() and N1′ represent expressions on a second reference connection. Preferably, the function f() may include the direction D1 of flow of the message containing f(), as in f(S1, N1, D1,...). In such a case, f() is selected such that the equation f′(S, N1′,D1′,...) = f(S, N2, D1,...) cannot be solved for N1′ without knowledge of S1 and S2. In this equation, D1′ is the flow direction indicator of the message containing f′() on the reference connection. Specific protocols satisfying this condition are protected from so-called intercept attacks.
Inventors
- 👤 Raymond Frederick Bird
- 👤 Inder Sarat Gopal
- 👤 Philippe Arnaud Janson
- 👤 Shay Kutten
- 👤 Refik Ahmet Molva
- 👤 Marcel Mordechai Yung
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 13:32
CPC Classifications
H; H04; H04L; H04L63/00; H04L63/08; G; G06; G06F; G06F21/00; G06F21/30; G06F21/44; G06F21/445; H04L9/00; H04L9/002; H04L9/32; H04L9/3218; H04L9/3271; G06F2221/00; G06F2221/21; G06F2221/2103
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
168 words
A method of authenticating users on a communications connection in a network, characterized in that it comprises the steps of (a) transmitting a first challenge N1 from a first user A to a second user B, (b) transmitting a first response to the first challenge and second challenge N2 from the second user to the first user, (c) verifying at the first user that the first response is correct, (d) transmitting a second response to the second challenge from the first user to the second user, and (e) verifying at the second user that the second response is correct, said first response being of the minimum form f(S1, N1,...), and said second response being of the minimum form g(S2, N2,...), where S1 and S2 are shared secrets between the first and second users and f() and g() are functions selected such that f′(S1, N1′,...) = g(S2, N2) cannot be solved for N1′ without knowledge of S1 and S2, wherein f′() and N1′ represent expressions on a reference connection.
Claim 2
Dependent Claim
21 words
The method of claim 1 wherein the secret S1 is the mathematical function f() and S2 is the mathematical function g().
Claim 3
Independent Claim
21 words
The method of claims 1 or 2 wherein S1 = S2 = S and wherein S is a data encryption key.
Claim 4
Independent Claim
69 words
The method of claims 1, 2 or 3 wherein f() further includes an indication of the direction D1 of flow of the message containing f(), as in f(S1, N1, D1,...) and f() is selected such that f′(S, N1′,D1′,...) = f(S, N2, D1,...) cannot be solved for N1′ without knowledge of S1 and S2, wherein D1′ is the flow direction indicator of the message containing f′() on the reference connection.
Claim 5
Dependent Claim
147 words
The method of claim 1 which can be restrained to a method of authenticating a user on a communications connection in a network, characterized in that it comprises the steps of (a) transmitting a first challenge N1 from a first user A to a second user B, (b) transmitting a first response to the first challenge from the second user to the first user, (c) verifying at the first user that the first response is correct, said first response being of the minimum form f(s1, N1, D1...), wherein S1 is a shared secret between the first and second users, D1 is an indication of the direction of flow of the message containing f() and f() is a function selected such that f′(S1, N1′,D1′,...) = f(S1, N1, D1,...) cannot be solved for N1′ without knowledge of S1, wherein f′(), N1′ and D1′ represent expressions on a reference connection.
Claim 6
Dependent Claim
22 words
The method of claim 5 wherein the secret S1 is the mathematical function f() and wherein S1 is a data encryption key.
Claim 7
Independent Claim
49 words
The method set forth in anyone of claims 1 to 6 wherein f() = E[q op E[r]], and g() = E[t], wherein op is a mathematical or boolean operation, q = q(N1, ...), r = r(D1, ...), t = t(N2, ...), E = data encryption with an encryption key.
Claim 8
Independent Claim
50 words
The method set forth in anyone of claims 1 to 6, where in f() = E[q op E[r]], and g() = E[t], wherein op is a mathematical or boolean operation, q = q(D1, ...), r = r(N1. ...), t = t(N2, ...), E = data encryption with an encryption key.
Claim 9
Independent Claim
23 words
The method set forth in anyone of claims 1 to 6 or 8 wherein f() = E[D1 op E[N1]] and g() = E[N2].
Claim 10
Independent Claim
23 words
The method set forth in anyone of claims 1 to 6 or 8 wherein f() = E[N1 op E[D1]] and g() = E[N2].
Claim 11
Independent Claim
37 words
The method set forth in anyone of claims 1 to 6 or 8 wherein f() = E [N1 op D1 op E[ N2 op E [N1]] and g() = E [N2 op E [N1]] op E [N1].
Claim 12
Independent Claim
34 words
The method set forth in anyone of claims 1 to 6 or 8 wherein f() = E [N1 op D1 op E [N2 op E [N1]] and g() = E [N2 op E [N1]].
Claim 13
Independent Claim
33 words
The method set forth in anyone of claims 1 to 6 or 8 wherein f() = Eb[N1] and g() = E [N2]. where Eb = encryption with data encryption key K op D1.
Claim 14
Dependent Claim
133 words
An arrangement at a network node for authenticating network users, characterized in that it comprises : means for transmitting a first challenge N1 to a user, means for receiving a first response to the first challenge and a second challenge N2 from the user, means for verifying the first response, means for transmitting a second response to the second challenge, and means for verifying a second response, said first response being of the minimum form f(S1, N1,...), and said second response being of the minimum form g(s2, N2,...), where S1 and S2 are shared secrets between authorized users and f() and g() are functions selected such that f′(S1, N1′,...) = g(S2, N2) cannot be solved for N1′ without knowledge of S1 and S2, wherein f′() and N1′ represent expressions on a reference connection.
Claim 15
Dependent Claim
21 words
The arrangement of claim 14 wherein the secret S1 is the mathematical function f() and S2 is the mathematical function g().
Claim 16
Dependent Claim
21 words
The arrangement of claims 14 or 15 wherein S1 = S2 = S and wherein S is a data encryption key.
Claim 17
Dependent Claim
75 words
The arrangement of claims 14, 15 or 16 wherein f() further includes an indication of the direction D1 of flow of the message containing f(), as in f(S1, N1, D1,...) and f() is selected such that f′(S, N1′,D1′,...) = f(S, N2, D1,...) cannot be solved for N1′ without knowledge of S1 and S2, wherein f′() indicates the reference connection and D1′ is the flow direction indicator of the message containing f′() on the reference connection.
Claim 18
Dependent Claim
123 words
The arrangement of claim 14 which can be restrained to an arrangement at a network node for authenticating a network user, characterized in that it comprises : means for transmitting a challenge N1 to a user, means for receiving a response to the challenge from the user, and means for verifying the response, said response being of the minimum form f(S1, N1, D1...), wherein S1 is a shared secret between the first and second users, D1 is an indication of the direction of flow of the message containing f() and f() is a function selected such that f′(S1, N1′,D1′,...) = f(S1, N1, D1,...) cannot be solved for N1′ without knowledge of S1, wherein f′(), N1′ and D1′ represent expressions on a reference connection.
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