US4649233A
Expired / Lapsed
US
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Method for establishing user authenication with composite session keys among cryptographically communicating nodes
Assignee: International Business Machines Corp
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Filing: 1985-04-11
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Granted: 1987-03-10
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Expires: 2005-04-11
Abstract
Abstract A method for authenticating nodes/users and in protecting data flow between nodes. This is facilitated by creating a dialogue involving authenticated encryption among the nodes. During each session, a key for use in cryptographic conversion is constructed among the node participants in order to permit symmetric authentication. The key is unique to the session. A different key is generated for each and every session. The building of the session key involves sharing of a minimal amount of information among the participants in the form of combining both a random number and authentication indicia.
Inventors
- 👤 Walter E. Bass
- 👤 Stephen M. Matyas
- 👤 Jonathan Oseas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:39
CPC Classifications
H; H04; H04L; H04L9/00; H04L9/002; H04L9/06; H04L9/0618; H04L9/0625; H04L9/0637; H04L9/08; H04L9/0816; H04L9/0838; H04L9/0841; H04L9/0844; H04L9/0861; H04L9/0869
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
155 words
A method for establishing a key commutatively between a pair of communicating nodes and for authenticating the node and user identities, said key being valid only for the duration of a single cryptographic session, each node of the pair having a local cryptographic facility including a pre-established cross-domain key and an identifier associated with the other node and user identity, comprising the steps at each node of: (a) generating a local random number, encrypting said random number under the cross-domain key, transmitting said encrypted random number to the other node, and decrypting under the cross-domain key an encrypted random number received from said other node; (b) forming a parameter by combining the attributes derived or associated with the identities of both nodes and users; (c) forming an interim key from the composite of the local random and received encrypted random numbers; and (d) combining the parameter with the interim key to produce the session key.
Claim 2
Independent Claim
155 words
A method for establishing a key commutatively between a pair of communicating nodes and for authenticating the node and user identities, said key being valid only for the duration of a single cryptographic session, each node of the pair having a local cryptographic facility including a pre-established cross-domain key and an identifier associated with the other node and user identity, comprising the steps at each node of: (a) generating a local random number, encrypting said random number under the cross-domain key, transmitting said encrypted random number to the other node, and decrypting under the cross-domain key an encrypted random number received from said other node; (b) forming a parameter by combining the attributes derived or associated with the identities of both nodes and users; (c) forming an interim key from the composite of the local random and received encrypted random numbers; and (d) combining the parameter with the interim key to produce the session key.
Claim 3
Dependent Claim
21 words
A method according to claim 1, wherein the cross-domain key includes a local and remote variant, all unidirectional keys being dissimilar.
Claim 4
Dependent Claim
28 words
A method according to claim 1, wherein the identifier associated with each node and user identity is selectively obtained by either table lookup or by way of computation.
Claim 5
Dependent Claim
45 words
A method according to claim 2, wherein the cryptographic facility of each node further includes no more than the local and remote variants of each of a plurality of distinguishable cross-domain keys corresponding to the number of nodes with which it can potentially cryptographically communicate.
Claim 6
Dependent Claim
33 words
A method according to claim 1, wherein the step of combining the parameter with the interim key to produce the session key includes the step of encrypting the parameter with the interim key.
Claim 7
Independent Claim
198 words
A method for establishing a key commutatively among n cryptographically communicating nodes and for authenticating node and user identities, said key being valid only for the duration of a single cryptographic session, each of the nodes having a local cryptographic facility including a plurality of pre-established cross-domain keys, and a concordance between a plurality of node and user identities and at least one identifier associated therewith, comprising the steps at each node of: (a) transmitting its node and user identity to the (n-1) other nodes and responsively obtaining the identity of said (n-1) other nodes; (b) generating a local random number, encrypting it under each of the pre-established cross-domain keys, transmitting each one of the set of encrypted random numbers to each one of the set of counterpart (n-1) other nodes, and decrypting under the counterpart cross-domain keys the encrypted random numbers received from the counterpart nodes; (c) forming a parameter by combining the identifies derived or associated with the identities of the n nodes and users; (d) forming an interim key from the composite of the local random and received encrypted random numbers; and (e) combining the parameter with the interim key to produce the session key.
Claim 8
Independent Claim
198 words
A method for establishing a key commutatively among n cryptographically communicating nodes and for authenticating node and user identities, said key being valid only for the duration of a single cryptographic session, each of the nodes having a local cryptographic facility including a plurality of pre-established cross-domain keys, and a concordance between a plurality of node and user identities and at least one identifier associated therewith, comprising the steps at each node of: (a) transmitting its node and user identity to the (n-1) other nodes and responsively obtaining the identity of said (n-1) other nodes; (b) generating a local random number, encrypting it under each of the pre-established cross-domain keys, transmitting each one of the set of encrypted random numbers to each one of the set of counterpart (n-1) other nodes, and decrypting under the counterpart cross-domain keys the encrypted random numbers received from the counterpart nodes; (c) forming a parameter by combining the identifies derived or associated with the identities of the n nodes and users; (d) forming an interim key from the composite of the local random and received encrypted random numbers; and (e) combining the parameter with the interim key to produce the session key.
Claim 9
Dependent Claim
17 words
A method according to claim 6, wherein each cross-domain key includes a local and remote variant thereof.
Claim 10
Dependent Claim
41 words
A method according to claim 6, wherein generated random numbers are encrypted under the local variant corresponding to each cross-domain key while any received encrypted random numbers from counterpart nodes are decrypted under the remote variant of the counterpart cross-domain key.
Claim 11
Dependent Claim
25 words
A method according to claim 6, wherein the local and received random numbers which form an interim key are encrypted under the counterpart remote variant.
Claim 12
Dependent Claim
33 words
A method according to claim 6, wherein the step of combining the parameter with the interim key to produce the session key includes the step of encrypting the parameter with the interim key.
Claim 13
Dependent Claim
27 words
A method according to claim 1 or 6, wherein the step of forming the interim key includes the exclusive OR'ing of the local and received random numbers.
Claim 14
Dependent Claim
32 words
A method according to claim 1 or 6, wherein the steps of combining the identifiers to form a parameter or forming a composite of local and received random numbers are commutative steps.
Claim 15
Dependent Claim
24 words
A method according to claim 1 or 6, wherein each identifier is a value ascertained as a one-way function of node/user identity or indicia.
Claim 16
Dependent Claim
35 words
A method according to claim 1 or 6, wherein there is provided the additional step of checking to verify that the session key so generated is the same at both the sending and receiving nodes.
Claim 17
Dependent Claim
48 words
A method as in claim 1 wherein the step of combining the parameter with the interim key to produce the session key includes the step of additively combining the attributes corresponding to the counterpart node and user identities, and then encrypting the additive combination with the interim key.
Claim 18
Dependent Claim
48 words
A method as in claim 6 wherein the step of combining the parameter with the interim key to produce the session key includes the step of additively combining the attributes corresponding to the counterpart node and user identities, and then encrypting the additive combination with the interim key.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-03-09 | 1990-09-08 | 1991-03-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-03-09 | 1994-09-08 | 1995-03-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-03-09 | 1998-09-08 | 1999-03-10 | $7700.00 | Window Closed / Lapsed |