US5956404A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital signature with auditing bits
Assignee: BT Americas Inc
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Filing: 1996-09-30
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Granted: 1999-09-21
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Expires: 2016-09-30
Abstract
Abstract A method for digitally signing a message by a tamper-resistant device to generate a digital signature. The method includes the step of hashing the message to form message bits; and encrypting with a private key the message bits, redundancy bits for the security of the signature, and auditing bits to form the digital signature for the message. The auditing bits provide an audit trail for the message. The auditing bits include one or more of the following categories: signature-packet version bits to identify the version of the device generating the signature; device ID bits to identify the token generating the digital signature; key ID bits to identify the private key; a packet-sequence number, which increments every time the device generates a signature to indicate the sequence of signatures generated; bits generated by hashing the prior signature to provide an auditing trail of signatures generated and a time-stamp to indicate the time when the signature is generated. The auditing bits may further include a random number.
Inventors
- 👤 Bruce Schneier
- 👤 John Kelsey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 16:01
CPC Classifications
H; H04; H04L; H04L9/00; H04L9/32; H04L9/3234; G; G06; G06Q; G06Q20/00; G06Q20/38; G06Q20/40; G06Q20/401; H04L9/3247; H04L9/3297; H04L9/50; H04L2209/00; H04L2209/56
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
135 words
A method for performing a cryptographically assured electronic transaction requested by a user module, and providing multiple independent audit trails therefor, comprising the steps performed by an application module of: (a) cryptographically interlocking with a user module; (b) receiving, from said user module, a cryptographically verifiable transaction request; (c) cryptographically verifying said received transaction request; (d) electronically performing said transaction; (e) logging said performed transaction as part of a digitally signed hash chain including at least one previously performed transaction, to provide a first cryptographically assured audit trail of said transaction; (f) cryptographically interlocking with an auditing module separate from said application module; and (g) transmitting said hash chain to said auditing module, to provide thereat a second cryptographically assured audit trail of said transaction, independent of said first audit trail in said application module.
Claim 2
Independent Claim
135 words
A method for performing a cryptographically assured electronic transaction requested by a user module, and providing multiple independent audit trails therefor, comprising the steps performed by an application module of: (a) cryptographically interlocking with a user module; (b) receiving, from said user module, a cryptographically verifiable transaction request; (c) cryptographically verifying said received transaction request; (d) electronically performing said transaction; (e) logging said performed transaction as part of a digitally signed hash chain including at least one previously performed transaction, to provide a first cryptographically assured audit trail of said transaction; (f) cryptographically interlocking with an auditing module separate from said application module; and (g) transmitting said hash chain to said auditing module, to provide thereat a second cryptographically assured audit trail of said transaction, independent of said first audit trail in said application module.
Claim 3
Dependent Claim
18 words
The method of claim 1 where said transaction request is for a digital timestamp of a user message.
Claim 4
Dependent Claim
30 words
The method of claim 2 where said second cryptographically assured audit trail includes a digital timestamp of the receipt, at said auditing module, of said first cryptographically assured audit trail.
Claim 5
Dependent Claim
25 words
The method of claim 1 where said application module is a time stamping module, and where said auditing module is a master time stamping module.
Claim 6
Dependent Claim
41 words
The method of claim 1 where said receiving step (b) occurs after each receipt of a transaction request from said user, and where said transmitting step (g) occurs after receiving a plurality of transaction requests from users of said application module.
Claim 7
Dependent Claim
35 words
The method of claim 1 where said application module is a bank module, and where said transaction is an electronic payment order from a guaranteed checking account of said user to an electronic payee module.
Claim 8
Dependent Claim
63 words
The method of claim 6 further comprising the step, after said step (a), of cryptographically interlocking with said electronic payee module, and wherein said user module sends said payee module an electronic check if a temporal interval between (i) said user module's interlock with said bank module, and (ii) said payee module's interlock with said bank module, is less than a predetermined limit.
Claim 9
Dependent Claim
25 words
The method of claim 7 where each said step of interlocking includes transmitting a signed certificate from said bank module to said module interlocking therewith.
Claim 10
Dependent Claim
16 words
The method of claim 8 where said signed certificate includes a timestamp from said bank module.
Claim 11
Dependent Claim
27 words
The method of claim 7 where said electronic check includes an account number of said user and an amount of money to be transferred to said payee.
Claim 12
Dependent Claim
24 words
The method of claim 6 further comprising the step of electronically reconciling account balance records held by said user module and said bank module.
Claim 13
Dependent Claim
45 words
The method of claim 11 where said reconciling step includes: (i) receiving, from said user module, a log of transactions conducted thereby; (ii) cryptographically verifying that said received log is proper; (iii) transmitting, to said user module, a verified balance of said user's account balance.
Claim 14
Dependent Claim
27 words
The method of claim 12 where said step of verifying said log includes checking that said log does not disagree with information available to said bank module.
Claim 15
Dependent Claim
20 words
The method of claim 12 where said step of verifying said log includes checking that said log is internally consistent.
Claim 16
Dependent Claim
17 words
The method of claim 1 where at least one of said modules is a tamper-resistant hardware token.
Claim 17
Dependent Claim
17 words
The method of claim 1 where at least one of said modules is a secure software application.
Claim 18
Dependent Claim
142 words
A cryptographic application module for performing a cryptographically assured electronic transaction requested by a user module, and providing multiple independent audit trails therefor, comprising: (a) means for cryptographically interlocking with a user module; (b) means for receiving, from said user module, a cryptographically verifiable transaction request; (c) means for cryptographically verifying said received transaction request; (d) means for electronically performing said transaction; (e) means for logging said performed transaction as part of a digitally signed hash chain including at least one previously performed transaction, to provide a first cryptographically assured audit trail of said transaction; (f) means for cryptographically interlocking with an auditing module separate from said application module; and (g) means for transmitting said hash chain to said auditing module, to provide thereat a second cryptographically assured audit trail of said transaction, independent of said first-audit trail in said application module.
Claim 19
Dependent Claim
142 words
A cryptographic application module for performing a cryptographically assured electronic transaction requested by a user module, and providing multiple independent audit trails therefor, comprising: (a) means for cryptographically interlocking with a user module; (b) means for receiving, from said user module, a cryptographically verifiable transaction request; (c) means for cryptographically verifying said received transaction request; (d) means for electronically performing said transaction; (e) means for logging said performed transaction as part of a digitally signed hash chain including at least one previously performed transaction, to provide a first cryptographically assured audit trail of said transaction; (f) means for cryptographically interlocking with an auditing module separate from said application module; and (g) means for transmitting said hash chain to said auditing module, to provide thereat a second cryptographically assured audit trail of said transaction, independent of said first-audit trail in said application module.
Claim 20
Dependent Claim
32 words
The application module of claim 17 configured as a bank module, wherein said transaction is an electronic payment order from a guaranteed checking account of said user to an electronic payment module.
Claim 21
Dependent Claim
23 words
The application module of claim 18 further comprising means for reconciling account balance records held by said user module and said bank module.
Claim 22
Dependent Claim
54 words
The application module of claim 19 wherein said means for reconciling includes: (i) means for receiving, from said user module, a log of transactions conducted thereby; (ii) means for cryptographically verifying that said received log is proper; and (iii) means for transmitting, to said user module, a verified balance of said user's account balance.
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) | 2002-09-20 | 2003-03-22 | 2003-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-09-20 | 2007-03-22 | 2007-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-09-20 | 2011-03-22 | 2011-09-21 | $7700.00 | Window Closed / Lapsed |