EP0636963A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Authentication system using one-time passwords
Assignee: International Business Machines Corp
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Filing: 1994-07-25
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Granted: —
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Expires: 2014-07-25
Abstract
Abstract A system for authenticating a user located at a requesting node to a resource such as a host application located at an authenticating node using one-time passwords that change pseudorandomly with each request for authentication. At the requesting node a non-time-dependent value is generated from nonsecret information identifying the user and the host application, using a secret encryption key shared with the authenticating node. The non-time-dependent value is combined with a time-dependent value to generate a composite value that is encrypted to produce an authentication parameter. The authentication parameter is reversibly transformed into an alphanumeric character string that is transmitted as a one-time password to the authenticating node. At the authenticating node the received password is transformed back into the corresponding authentication parameter, which is decrypted to regenerate the composite value. The non-time-dependent value is replicated at the authenticating node using the same nonsecret information and encryption key shared with the requesting node. The locally generated non-time-dependent value is combined with the regenerated composite value to regenerate the time-dependent value. The user is authenticated if the regenerated time-dependent value is within a predetermined range of a time-dependent value that is locally generated at the authenticating node. Passwords found not to have a corresponding authentication parameter are trivially rejected by the authenticating node to avoid unnecessary processing steps. A encryption system for transforming short blocks into encrypted blocks of the same length is also disclosed.
Inventors
- 👤 Richard Henry Guski
- 👤 Raymond Craig Larson
- 👤 Stephen Michael Matyas Jr
- 👤 Donald Byron Johnson
- 👤 Don Coppersmith
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 21:07
CPC Classifications
H; H04; H04L; H04L63/00; H04L63/08; H04L63/083; H04L63/0838; G; G06; G06F; G06F21/00; G06F21/30; G06F21/31; H04L12/00; H04L12/02; H04L12/22; H04L63/0846; H04L9/00; H04L9/08; H04L9/0816; H04L9/0819; H04L9/0822; H04L9/088; H04L9/0894; H04L9/32; H04L9/3226; H04L9/3228; H04L2209/00; H04L2209/20; H04W; H04W12/00; H04W12/60; H04W12/61
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
140 words
An authentication method comprising the steps of: generating an authentication parameter as a function of time-dependent information using a predetermined first transformation, said predetermined first transformation having an inverse transformation such that said time-dependent information may be regenerated from said authentication parameter using said inverse transformation; generating a time-dependent password comprising a character string from said authentication parameter using a predetermined second transformation, said predetermined second transformation having an inverse transformation such that said authentication parameter may be regenerated from said password using said inverse transformation; and presenting said password to an authenticator, whereby said authenticator may regenerate said time-dependent information from said password by regenerating said authentication parameter from the password presented to said authenticator using the inverse of said second transformation and then regenerating said time-dependent information from said authentication parameter using the inverse of said first transformation.
Claim 2
Dependent Claim
44 words
The method of claim 1, further comprising the steps of: regenerating said authentication parameter from the password presented to said authenticator using the inverse of said second transformation; and regenerating said time-dependent information from said authentication parameter using the inverse of said first transformation.
Claim 3
Dependent Claim
40 words
The method of claim 2, further comprising the steps of: comparing the regenerated time-dependent information with reference time-dependent information; and granting access to a resource in accordance with the comparison of said regenerated time-dependent information with said reference time-dependent information.
Claim 4
Independent Claim
25 words
The method of one of claims 1 to 3, wherein said first transformation is a cryptographic transformation using an encryption key shared with said authenticator.
Claim 5
Independent Claim
42 words
The method of one of claims 1 to 4, wherein said step of generating an authentication parameter comprises the steps of: combining said time-dependent information with non-time-dependent information to generate composite information; and encrypting said composite information to generate said authentication parameter.
Claim 6
Dependent Claim
20 words
The method of claim 5, wherein said non-time-dependent information is generated by encrypting nonsecret information identifying a request for authentication.
Claim 7
Independent Claim
18 words
The method of one of claims 1 to 6, wherein said password comprises a string of alphanumeric characters.
Claim 8
Independent Claim
37 words
The method of one of claims 1 to 7, wherein said authentication parameter has a predetermined first number of possible values, said character string having a predetermined second number of possible values greater than said first number.
Claim 9
Independent Claim
62 words
The method of one of claims 1 to 8, comprising the further steps of: determining whether the password presented to the authenticator has a corresponding authentication parameter from which the password could have been generated using said second transformation; further processing said password if it is determined to have said corresponding authentication parameter, otherwise denying access to a resource without further processing.
Claim 10
Independent Claim
17 words
The method of one of claims 1 to 9, wherein said time-dependent information comprises time-of-day (TOD) information.
Claim 11
Independent Claim
178 words
The method of one of claims 1 to 10 in a system in which a valid password is generated by generating an authentication parameter as a function of time-dependent information using a predetermined first transformation and then generating a time-dependent password comprising a character string from said authentication parameter using a predetermined second transformation, said predetermined first transformation having an inverse transformation such that said time-dependent information may be regenerated from said password using said inverse transformation, said predetermined second transformation having an inverse transformation such that said authentication parameter may be regenerated from said password using said inverse transformation, a method of validating a password presented to an authenticator comprising the steps of: regenerating said authentication parameter from the password presented to said authenticator using the inverse of said second transformation; regenerating said time-dependent information from said regenerated authentication parameter using the inverse of said first transformation; comparing the regenerated time-dependent information with reference time-dependent information; and granting access to a resource in accordance with the comparison of said regenerated time-dependent information with said reference time-dependent information.
Claim 12
Independent Claim
52 words
The method of one of claims 2 to 11, wherein said first transformation is a cryptographic transformation using an encryption key shared with said authenticator, said encryption key having a corresponding decryption key, said step of regenerating said time-dependent information comprising the step of decrypting said authentication parameter using said decryption key.
Claim 13
Independent Claim
40 words
The method of one of claims 1 to 12, wherein said password contains a plurality of sets of bits, each of said sets of bits being generated as a function of a corresponding set of bits of said authentication parameter.
Claim 14
Dependent Claim
18 words
The method of claim 13, wherein each of said sets of bits in said password represents a character.
Claim 15
Dependent Claim
20 words
The method of claim 13 or 14, wherein the corresponding sets of bits in said authentication parameter overlap one another.
Claim 16
Dependent Claim
147 words
An authentication method comprising the steps of: generating time-dependent information at a requesting node; combining said time-dependent information with non-time-dependent information to generate composite information, the combining being such that said time-dependent information can be regenerated from said composite information by combining said composite information with said non-time-dependent information; generating an authentication code from said composite information using a predetermined transformation, said predetermined transformation having an inverse transformation such that said composite information may be regenerated from said authentication code using said inverse transformation; transmitting said authentication code to an authenticator located at an authenticating node, whereby said authenticator may regenerate said time-dependent information from said authentication code by regenerating said composite information from the authentication code transmitted to said authenticator using the inverse of said predetermined transformation and then regenerating said time-dependent information from said composite information by combining said composite information with said non-time-dependent information.
Claim 17
Dependent Claim
46 words
The method of claim 16, further comprising the steps of: regenerating said composite information from the authentication code transmitted to said authenticator using the inverse of said transformation; and regenerating said time-dependent information from said composite information by combining said composite information with said non-time-dependent information.
Claim 18
Dependent Claim
40 words
The method of claim 17, further comprising the steps of: comparing the regenerated time-dependent information with reference time-dependent information; and granting access to a resource in accordance with the comparison of said regenerated time-dependent information with said reference time-dependent information.
Claim 19
Independent Claim
32 words
The method of one of claims 16 to 18, wherein said non-time-dependent information and said time-dependent information each comprise bit strings and are combined bitwise by the operation of modulo 2 addition.
Claim 20
Independent Claim
25 words
The method of one of claims 16 to 19, wherein said predetermined transformation is a cryptographic transformation using an encryption key shared with said authenticator.
Claim 21
Independent Claim
190 words
A method of transforming an input data block containing n bits into an output data block containing n bits, where n is an even integer, said method comprising the steps of: (a) partitioning the input data block into first and second halves each containing n/2 bits; (b) subjecting said halves of said input data block to a plurality of rounds in which first and second input halves are transformed into first and second output halves serving as the corresponding input halves for the subsequent round, each of said rounds comprising the steps of: (1) generating a predetermined first function of the first input half; (2) generating the first output half as a predetermined second function of said predetermined first function and the second input half; and (3) generating the second output half as a predetermined third function of the first input half; at least one of said first, second and third functions involving a permutation of a set of n/2 input bits to yield n/2 output bits, said permutation being different for each of said rounds; and (c) recombining said first and second halves to produce said output data block.
Claim 22
Independent Claim
217 words
A method of transforming an input data block containing n bits into an output data block containing n bits, where n is an even integer, said method comprising the steps of: (a) partitioning the input data block into first and second halves each containing n/2 bits; (b) subjecting said halves of said input data block to a plurality of rounds in which first and second input halves are transformed into first and second output halves, the output halves of a given round serving as the corresponding input halves for the subsequent round, each of said rounds comprising the steps of: (1) padding said first input half with padding bits to generate a m-bit input value, where m is greater than n/2; (2) encrypting said m-bit input value using a predetermined m-bit encryption procedure to generate a 64-bit output value; (3) selecting predetermined bits of said m-bit output value to form an n/2-bit output value; (4) generating the first output half for said round as a function of the modulo 2 sum of said n/2-bit output value and the second input half for said round; and (5) setting the second output half for said round equal to the first input half for said round; and (c) recombining said first and second halves to produce said output data block.
Claim 23
Dependent Claim
40 words
The method of claim 22, wherein m is 64 and said predetermined encryption procedure is the DES encryption procedure, and said predetermined m-bit encryption procedure has a key and wherein the same key is used for each of said rounds.
Claim 24
Dependent Claim
218 words
Authentication apparatus comprising: means for generating an authentication parameter as a function of time-dependent information using a predetermined first transformation, said predetermined first transformation having an inverse transformation such that said time-dependent information may be regenerated from said authentication parameter using said inverse transformation; means for generating a time-dependent password comprising a character string from said authentication parameter using a predetermined second transformation, said predetermined second transformation having an inverse transformation such that said authentication parameter may be regenerated from said password using said inverse transformation; and means for presenting said password to an authenticator, whereby said authenticator may regenerate said time-dependent information from said password for comparison with reference time-dependent information by regenerating said authentication parameter from the password presented to said authenticator using the inverse of said second transformation and then regenerating said time-dependent information from said authentication parameter using the inverse of said first transformation; means for regenerating said authentication parameter from the password presented to said authenticator using the inverse of said second transformation; means for regenerating said time-dependent information from said authentication parameter using the inverse of said first transformation; means for comparing the regenerated time-dependent information with reference time-dependent information; and means for granting access to a resource in accordance with a comparison of said regenerated time-dependent information with reference time-dependent information.
Claim 25
Dependent Claim
188 words
Authentication apparatus comprising: means for generating time-dependent information at a requesting node; means for combining said time-dependent information with non-time-dependent information to generate composite information, the combining being such that said time-dependent information can be regenerated from said composite information by combining said composite information with said non-time-dependent information; means for generating an authentication code from said composite information using a predetermined transformation, said predetermined transformation having an inverse transformation such that said composite information may be regenerated from said authentication code using said inverse transformation; means for transmitting said password to an authenticator located at an authenticating node, whereby said authenticator may regenerate said time-dependent information from said authentication code by regenerating said composite information from the authentication code transmitted to said authenticator using the inverse of said transformation and then regenerating said time-dependentinformation from said composite information by combining said composite information with said non-time-dependent information; means for regenerating said composite information from the authentication code transmitted to said authenticator using the inverse of said transformation; and means for regenerating said time-dependent information from said composite information by combining said composite information with said non-time-dependent information.
Claim 26
Dependent Claim
195 words
Apparatus for transforming an input data block containing n bits into an output data block containing n bits, where n is an even integer, said apparatus comprising: (a) means for partitioning the input data block into first and second halves each containing n/2 bits; (b) means for subjecting said halves of said input data block to a plurality of rounds in which first and second input halves are transformed into first and second output halves serving as the corresponding input halves for the subsequent round, said means including means operative on each of said rounds for: (1) generating a predetermined first function of the first input half; (2) generating the first output half as a predetermined second function of said predetermined first function and the second input half; and (3) generating the second output half as a predetermined third function of the first input half; at least one of said first, second and third functions involving a permutation of a set of n/2 input bits to yield n/2 output bits, said permutation being different for each of said rounds; and (c) means for recombining said first and second halves to produce said output data block.
Claim 27
Dependent Claim
222 words
Apparatus for transforming an input data block containing n bits into an output data block containing n bits, where n is an even integer, said apparatus comprising: (a) means for partitioning the input data block into first and second halves each containing n/2 bits; (b) means for subjecting said halves of said input data block to a plurality of rounds in which first and second input halves are transformed into first and second output halves, the output halves of a given round serving as the corresponding input halves for the subsequent round, said means including means operative on each of said rounds for: (1) padding said first input half with padding bits to generate a m-bit input value, where m is greater than n/2; (2) encrypting said m-bit input value using a predetermined m-bit encryption procedure to generate a 64-bit output value; (3) selecting predetermined bits of said m-bit output value to form an n/2-bit output value; (4) generating the first output half for said round as a function of the modulo 2 sum of said n/2-bit output value and the second input half for said round; and (5) setting the second output half for said round equal to the first input half for said round; and (c) means for recombining said first and second halves to produce said output data block.
References Cited (Backward Citations)
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