EP0798673A1
Expired / Lapsed
EP
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Method of securely loading commands in a smart card
Assignee: Koninklijke KPN NV
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Filing: 1996-03-29
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Granted: —
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Expires: 2016-03-29
Abstract
Abstract The invention relates to a method of securely loading and validating commands (COM) in a smart card (SC). Especially in the case where application-specific commands are loaded by an application provider (AP), that is off-line with respect to the card issuer (CI), it must be ensured that the commands are valid. The invention provides a method involving the protection of the commands (COM) by means of authentication codes, these codes (MAC1, MAC2) being produced using two different keys: one key (K1) is stored by the card issuer (CI), the other (K2) by a trusted third party (TTP). A further authentication code (MAC3), produced using a key from a set of keys (K3*), may be utilized to selectively validate commands for individual applications (e.g. AP1, AP2).
Inventors
- 👤 Michiel Marco Paul Drupsteen
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 00:29
CPC Classifications
G; G07; G07F; G07F7/00; G07F7/08; G07F7/10; G07F7/0806; G07F7/0813; G07F7/082; G06; G06F; G06F21/00; G06F21/50; G06F21/57; G06F21/572; G06Q; G06Q20/00; G06Q20/30; G06Q20/34; G06Q20/341; G06Q20/355; G06Q20/3552; G07F7/1008
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
124 words
Method of securely loading commands (COM) in a smart card (SC) by a first party (AP), the card (SC) being issued by a second party (CI), the method comprising the steps of: - the second party (CI) producing a first authentication code (MAC1) of a command using a first key (K1), - a third party (TTP) producing a second authentication code (MAC2) of the command using a second key (K2), - transferring the command (COM) with the codes (MAC1, MAC2) to the card, - the card (SC) validating the command (COM) by reproducing the first (MAC1) and second (MAC2) authentication codes using the first (K1) and the second (K2) key respectively and comparing the reproduced codes (MAC1', MAC2') with the transferred codes (MAC1, MAC2).
Claim 2
Dependent Claim
35 words
Method according to claim 1, wherein the transferring to the card (SC) and the subsequent validation are repeated when the validation fails, the use of the loaded command (COM) being blocked until the validation succeeds.
Claim 3
Dependent Claim
31 words
Method according to claim 2, wherein the loaded command (COM) is permanently disabled if the validation fails a predetermined number (N) of times, the number (N) preferably being less than ten.
Claim 4
Dependent Claim
27 words
Method according to claim 3, wherein the disabling is performed by the card (1) changing the key (K1) of the second party (CI) stored in the card.
Claim 5
Dependent Claim
17 words
Method according to any of the preceding claims, wherein the command (COM) is an application-specific command (ASC).
Claim 6
Dependent Claim
28 words
Method according to any of the preceding claims, wherein the first (MAC1) and/or second (MAC2) authentication codes are message authentication codes produced according to the ANSI X9.19 standard.
Claim 7
Dependent Claim
51 words
Method according to any of the preceding claims, wherein the card contains several applications (e.g. AP1, AP2), each application being provided with an individual third key (e.g. K3-2) for validating a command provided with a third authentication code (MAC3), said third authentication code being produced using the individual third key (K3-2).
Claim 8
Dependent Claim
36 words
Method according to any of the preceding claims, wherein the second party (CI) produces a fourth authentication code (MAC4) of the command (COM), said fourth code (MAC4) not involving the first (K1) or second (K2) key.
Claim 9
Dependent Claim
43 words
Method according to any of the preceding claims, wherein the card comprises a flag register (FR), each flag (F-1, F-2, ...) corresponding with a command of the processor (11), the execution of a command being inhibited if its flag (e.g. F-2) is set.
Claim 10
Dependent Claim
68 words
Card (1), comprising a substrate (2) and an integrated circuit (10) having a processor (11) and a memory (12), the memory containing keys (e.g. K1, K2), characterised in that the integrated circuit (10) is arranged to regenerate, using at least two keys (e.g. K1, K2), authentication codes (MAC1, MAC2) of a received command (COM) and to compare regenerated authentication codes (MAC1', MAC2') with received authentication codes (MAC1, MAC2).
Claim 11
Dependent Claim
40 words
Card according to claim 10, the memory (12) comprising a data structure having individual applications (e.g. AP1, AP2), each application containing an individual key (e.g. K3-1, K3-2) for regenerating authentication codes and selectively loading commands associated with the authentication codes.
Claim 12
Dependent Claim
42 words
Card according to claim 10 or 11, the memory (12) comprising a flag register (FR), each flag (F-1, F-2, ...) corresponding with a command of the processor (11), the execution of a command being inhibited if its flag (e.g. F-2) is set.
References Cited (Backward Citations)
EP0218176A2
Cited
DE4119924A1
Cited
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