US5349642A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for authentication of client server communication
Assignee: EMC Corp
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Filing: 1992-11-03
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Granted: 1994-09-20
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Expires: 2012-11-03
Abstract
Abstract The present invention provides a method and apparatus for message packet authentication to prevent the forging of message packets. After a message packet is created, a secret session key is preappended to the message, and a message digesting algorithm is executed on the altered message to create a message digest. A portion of the message digest, referred to as the signature, is then appended to the actual message when it is sent over the wire. The receiving station strips the signature from the message, preappends the same secret session key and creates its own message digest. The signature of the digest created by the receiving station is compared to the signature of the digest appended by the sending station. If there is a match, an authentic message is assumed. If there is no match, the message is considered as invalid and discarded. An advantage of the present invention is that the session key is never transmitted over the wire. The receiving station (server) already has the key and uses the key along with the message data to recalculate the message digest upon receiving the packet. The shared secret key (session key) is generated during initiation of the NCP session. In addition, cumulative state information is maintained by both the sending station and the receiving station. This state information is also used to authenticate messages.
Inventors
- 👤 Kevin Kingdon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 07:39
CPC Classifications
H; H04; H04L; H04L69/00; H04L69/16; H04L63/00; H04L63/06; H04L63/061; H04L63/067; H04L63/08; H04L63/083; H04L63/12; H04L9/00; H04L9/08; H04L9/0816; H04L9/0819; H04L9/0827; H04L9/32; H04L9/3236; H04L9/3247
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
142 words
A method of authenticating a message transmitted between a sender and a receiver comprising the steps of: generating a message at said sender; combining a session key with said message to create a first appended message; calculating a first digest of said first appended message; combining a first portion of said first digest with said message to create a transmit message; transmitting said transmit message to said receiver; removing said first portion of said first digest from said transmit message to result in said message; combining said session key with said message to generate a second appended message; calculating a second digest of said second appended message; comparing said said portion of said first digest and a second portion of said second digest; authenticating said message when said first portion of said first digest matches said second portion of said second digest.
Claim 2
Independent Claim
142 words
A method of authenticating a message transmitted between a sender and a receiver comprising the steps of: generating a message at said sender; combining a session key with said message to create a first appended message; calculating a first digest of said first appended message; combining a first portion of said first digest with said message to create a transmit message; transmitting said transmit message to said receiver; removing said first portion of said first digest from said transmit message to result in said message; combining said session key with said message to generate a second appended message; calculating a second digest of said second appended message; comparing said said portion of said first digest and a second portion of said second digest; authenticating said message when said first portion of said first digest matches said second portion of said second digest.
Claim 3
Independent Claim
15 words
The method of claim I wherein said sender is a client in a client/server network.
Claim 4
Dependent Claim
15 words
The method of claim 1 wherein said receiver is a server in a client/server network.
Claim 5
Dependent Claim
30 words
The method of claim 1 wherein said step of calculating a first digest of said first appended message is accomplished by executing a digest algorithm on said first appended message.
Claim 6
Dependent Claim
14 words
The method of claim 4 wherein said digest algorithm is an MD4 digest algorithm.
Claim 7
Dependent Claim
28 words
The method of claim 4 wherein a current state of said sender is used as an initial state when executing said digest algorithm to create said first digest.
Claim 8
Dependent Claim
25 words
The method of claim 6 wherein said current state is used as an initial state when executing said digest algorithm to create said second digest.
Claim 9
Dependent Claim
17 words
The method of claim 7 wherein said current state is advanced when an authenticated message is received.
Claim 10
Dependent Claim
19 words
The method of claim 8 wherein said current state is not advanced when an authenticated message is not received.
Claim 11
Dependent Claim
73 words
The method of claim 1 wherein said session key is generated by the steps of: providing a random number sequence challenge to said sender; requesting a password from a user of said sender; generating a first pass digest from said password; combining said first pass digest and said challenge in a buffer; generating a buffer digest of said buffer; defining said session key as a first number of bytes of said buffer digest.
Claim 12
Dependent Claim
160 words
Apparatus for authenticating a message transmitted between a sender and a receiver comprising: means for generating a message at said sender; means for combining a session key with said message to create a first appended message; means for calculating a first digest of said first appended message; means for combining said a first portion of said first digest with said message to create a transmit message; means for transmitting said transmit message to said receiver; means for removing said first portion of said first digest from said transmit message to result in said message; means for combining said session key with said message to generate a second appended message; means for calculating a second digest of said second appended message; means for comparing said said first portion of said first digest and a second portion of said second digest; means for authenticating said message when said first portion of said first digest matches said second portion of said second digest.
Claim 13
Dependent Claim
160 words
Apparatus for authenticating a message transmitted between a sender and a receiver comprising: means for generating a message at said sender; means for combining a session key with said message to create a first appended message; means for calculating a first digest of said first appended message; means for combining said a first portion of said first digest with said message to create a transmit message; means for transmitting said transmit message to said receiver; means for removing said first portion of said first digest from said transmit message to result in said message; means for combining said session key with said message to generate a second appended message; means for calculating a second digest of said second appended message; means for comparing said said first portion of said first digest and a second portion of said second digest; means for authenticating said message when said first portion of said first digest matches said second portion of said second digest.
Claim 14
Dependent Claim
15 words
The apparatus of claim 11 wherein said sender is a client in a client/server network.
Claim 15
Dependent Claim
15 words
The apparatus of claim 11 wherein said receiver is a server in a client/server network.
Claim 16
Dependent Claim
26 words
The apparatus of claim 11 wherein said first digest of said first appended message is calculated by executing a digest algorithm on said first appended message.
Claim 17
Dependent Claim
14 words
The apparatus of claim 14 wherein said digest algorithm is an MD4 digest algorithm.
Claim 18
Dependent Claim
28 words
The apparatus of claim 14 wherein a current state of said sender is used as an initial state when executing said digest algorithm to create said first digest.
Claim 19
Dependent Claim
25 words
The apparatus of claim 16 wherein said current state is used as an initial state when executing said digest algorithm to create said second digest.
Claim 20
Dependent Claim
17 words
The apparatus of claim 17 wherein said current state is advanced when an authenticated message is received.
Claim 21
Dependent Claim
19 words
The apparatus of claim 18 wherein said current state is not advanced when an authenticated message is not received.
Claim 22
Dependent Claim
84 words
The apparatus of claim 11 further including means for generating a session key comprising: means for providing a random number sequence challenge to said sender; means for requesting a password from a user of said sender; means for generating a first pass digest from said password; means for combining said first pass digest and said challenge in a buffer; means for generating a buffer digest of said buffer; means for defining said session key as a first number of bytes of said buffer digest.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-09-19 | 1998-03-21 | 1998-09-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-09-19 | 2002-03-21 | 2002-09-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-09-19 | 2006-03-21 | 2006-09-20 | $7700.00 | Window Closed / Lapsed |