US5745571A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cryptographic communications method and system
Assignee: Telstra Corp Ltd
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Filing: 1993-03-30
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Granted: 1998-04-28
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Expires: 2013-03-30
Abstract
Abstract A method for loading secret data, such as an application key, on a smart card (6), which involves storing a random key on the card (6), encrypting the random key on the basis of a public key, and providing the encrypted random key to a central processing station (4). The encrypted random key is decrypted at the central station on the basis of a secret key, and the station (4) encrypts data on the basis of the random key and transmits it to the smart card (6). The smart card decrypts the encrypted data on the basis of the random key. The random key can be generated internally and stored on read protected memory (23) of the card (6). The public key encrypting and secret key decrypting steps may be based on the RSA algorithm, using a small encryption exponent.
Inventors
- 👤 Edward Andrew Zuk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:58
CPC Classifications
G; G07; G07F; G07F7/00; G07F7/08; G07F7/10; G07F7/1008; G06; G06Q; G06Q20/00; G06Q20/30; G06Q20/34; G06Q20/341; G06Q20/355; G06Q20/3552; G06Q20/36; G06Q20/367; G06Q20/3674; G06Q20/38; G06Q20/40; G06Q20/409; G06Q20/4097; G06Q20/40975; G07F7/1016; H; H04; H04L; H04L9/00; H04L9/08; H04L9/0816; H04L9/0819; H04L9/0825; H04L9/0861; H04L9/0877; H04L9/30; H04L9/3006; H04L9/302
Claims Analysis
Total Claims: 43
Claim 1
Independent Claim
77 words
A cryptographic communications method comprising: storing a random key on a smart card; encrypting said random key using a public key and providing the encrypted random key to a central processing station; decrypting said encrypted random key at said central station using a secret key; encrypting data using said random key and transmitting the encrypted data from said central station to said smart card; and decrypting the encrypted data at said smart card using said random key.
Claim 2
Dependent Claim
77 words
A cryptographic communications method comprising: storing a random key on a smart card; encrypting said random key using a public key and providing the encrypted random key to a central processing station; decrypting said encrypted random key at said central station using a secret key; encrypting data using said random key and transmitting the encrypted data from said central station to said smart card; and decrypting the encrypted data at said smart card using said random key.
Claim 3
Dependent Claim
27 words
A communications method as claimed in claim 1, wherein said random key is stored in a memory area of said smart card which is not externally addressable.
Claim 4
Dependent Claim
18 words
A communications method as claimed in claim 2, wherein said data includes an application key for said card.
Claim 5
Dependent Claim
17 words
A communications method as claimed in claim 3, including generating said random key on said smart card.
Claim 6
Dependent Claim
34 words
A communications method as claimed in claim 4, including deleting at least one of said random key, said public key, and a program code for encrypting using said public key, after receiving said data.
Claim 7
Dependent Claim
38 words
A communications method as claimed in claim 5, including storing an identification number on said smart card, transmitting said identification number to said central station, and accessing said secret key at said central station using said identification number.
Claim 8
Dependent Claim
27 words
A communications method as claimed in claim 6, including generating said public and secret keys at said station and storing said secret key using said identification number.
Claim 9
Dependent Claim
20 words
A communications method as claimed in claim 7, wherein said public and secret keys are unique for said smart card.
Claim 10
Dependent Claim
22 words
A communications method as claimed in claim 7, wherein said public and secret keys are unique for a batch of smart cards.
Claim 11
Dependent Claim
32 words
A communications method as claimed in claim 7, wherein the pubic key encrypting and secret key decrypting steps comprise an RSA based algorithm, using a modulus m and a small encryption exponent.
Claim 12
Dependent Claim
13 words
A communications method as claimed in claim 10, wherein said exponent is three.
Claim 13
Dependent Claim
22 words
A communications method as claimed in claim 10, including keeping said modulus secret and using said modulus to authenticate said smart card.
Claim 14
Dependent Claim
19 words
A communications method as claimed in claim 10, including using said encrypted random key to authenticate said smart card.
Claim 15
Dependent Claim
33 words
A communications method as claimed in claim 10, wherein said algorithm comprises encrypting and decrypting a value Z using: Z.sup.b *(2.sup.-R).sup.(b-1) (mod m) where b is the exponent and R is a constant.
Claim 16
Dependent Claim
81 words
A communications system comprising smart card means and a central processing station, said smart card means including: means for storing a random key on a smart card, means for encrypting said random key using a public key; and means for decrypting data encrypted using said random key; and said central station including: means for decrypting the encrypted random key using a secret key, and means for encrypting data using said random key and transmitting the encrypted data to said smart card.
Claim 17
Dependent Claim
81 words
A communications system comprising smart card means and a central processing station, said smart card means including: means for storing a random key on a smart card, means for encrypting said random key using a public key; and means for decrypting data encrypted using said random key; and said central station including: means for decrypting the encrypted random key using a secret key, and means for encrypting data using said random key and transmitting the encrypted data to said smart card.
Claim 18
Dependent Claim
16 words
A communications system as claimed in claim 15, wherein said storing means is not externally addressable.
Claim 19
Dependent Claim
18 words
A communications system as claimed in claim 16, wherein said data includes an application key for said card.
Claim 20
Dependent Claim
24 words
A communications system as claimed in claim 17, wherein said smart card means includes means for generating said random key on said smart card.
Claim 21
Dependent Claim
45 words
A communications system as claimed in claim 18, wherein said smart card includes program code for encrypting using said public key, wherein at least one of said program code, said public key and said random key are deleted after said smart card receives said data.
Claim 22
Dependent Claim
41 words
A communications system as claimed in claim 19, wherein said smart card includes an identification number, and means for transmitting said identification number to said central station, said central station including means for accessing said secret key using said identification number.
Claim 23
Dependent Claim
30 words
A communications system as claimed in claim 20, wherein said central station includes means for generating said public and secret keys and storing said secret key using said identification number.
Claim 24
Dependent Claim
20 words
A communications system as claimed in claim 21, wherein said public and secret keys are unique for said smart card.
Claim 25
Dependent Claim
22 words
A communications system as claimed in claim 21, wherein said public and secret keys are unique for a batch of smart cards.
Claim 26
Dependent Claim
34 words
A communications system as claimed in claim 21, wherein said public key encrypting means and said secret key decrypting means execute an RSA based algorithm, using a modulus m and a small encryption exponent.
Claim 27
Dependent Claim
13 words
A communications system as claimed in claim 24, wherein said exponent is three.
Claim 28
Dependent Claim
21 words
A communications system as claimed in claim 24, wherein said modulus is kept secret and used to authenticate said smart card.
Claim 29
Dependent Claim
20 words
A communications system as claimed in claim 24, wherein said encrypted random key is used to authenticate said smart card.
Claim 30
Dependent Claim
33 words
A communications system as claimed in claim 24, wherein said algorithm comprises encrypting and decrypting a value Z using: Z.sup.b *(2.sup.-R).sup.(b-1) (mod m) where b is the exponent and R is a constant.
Claim 31
Independent Claim
94 words
A method of initializing a smart card comprising: generating a random key; storing said random key in a memory area of said smart card which is not externally addressable; encrypting said random key using a public key; providing a central processing station with the encrypted random key; decrypting said encrypted random key at said central station using a secret key; encrypting secret data at said central station using said random key; transmitting the encrypted secret data to said smart card; and decrypting said encrypted secret data at said smart card using said random key.
Claim 32
Independent Claim
94 words
A method of initializing a smart card comprising: generating a random key; storing said random key in a memory area of said smart card which is not externally addressable; encrypting said random key using a public key; providing a central processing station with the encrypted random key; decrypting said encrypted random key at said central station using a secret key; encrypting secret data at said central station using said random key; transmitting the encrypted secret data to said smart card; and decrypting said encrypted secret data at said smart card using said random key.
Claim 33
Dependent Claim
19 words
A method as claimed in claim 29, wherein said secret data includes an application key for said smart card.
Claim 34
Dependent Claim
16 words
A method as claimed in claim 30, wherein said random key is generated on said card.
Claim 35
Dependent Claim
38 words
A method as claimed in claim 30, including deleting at least one of said random key, said public key and a program code for encrypting using said public key from said smart card after receiving said secret data.
Claim 36
Dependent Claim
22 words
A method as claimed in claim 30, including generating said public and secret keys for said smart card at said central station.
Claim 37
Dependent Claim
34 words
A method as claimed in claim 30, wherein said public key encrypting and secret key decrypting steps comprise a Montgomery modulo reduced RSA based algorithm, using a modulus m and a small encryption exponent.
Claim 38
Dependent Claim
36 words
A smart card comprising: read protected memory for storing a random key and a public key; means for encrypting said random key using said public key; and means for decrypting encrypted data using said random key.
Claim 39
Dependent Claim
36 words
A smart card comprising: read protected memory for storing a random key and a public key; means for encrypting said random key using said public key; and means for decrypting encrypted data using said random key.
Claim 40
Dependent Claim
15 words
A smart card as claimed in claim 35, wherein said data includes an application key.
Claim 41
Dependent Claim
15 words
A smart card as claimed in claim 35, including means for generating said random key.
Claim 42
Dependent Claim
37 words
A smart card as claimed in claim 35, including means for deleting at least one of said random key and said public key and a program code for encrypting using said public key after receiving said data.
Claim 43
Dependent Claim
35 words
A smart card as claimed in claim 35, wherein said means for encrypting executes a public key component of a Montgomery modulo reduced RSA based algorithm, using a modulus m and a small encryption exponent.
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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) | 2001-04-27 | 2001-10-27 | 2002-04-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-04-27 | 2005-10-27 | 2006-04-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-04-27 | 2009-10-27 | 2010-04-28 | $7700.00 | Window Closed / Lapsed |