Smart Card Handbook phần 5

Nếu quyền lực là tắt hoặc thất bại tạm thời, nội dung của bộ nhớ RAM là không xác định. một bộ nhớ dẫn đến nhảy chương trình không kiểm soát được hoặc lỗi tính toán đơn giản trong bộ vi xử lý. Những hành động đó bị lỗi có thể được sử dụng để xác định khóa bí mật bằng cách sử dụng các kỹ thuật phân tích lỗi sự khác biệt giữa (DFA), | Data Transmission Protocols 419 Terminal Smart Card TPDU NAD PCB LEN APDU EDC 00 00 06í A4 00 00 02 3F 00 A2 SELECT FILE FID 3F00 response to SELECT FILE TPDU NAD PCB LEN APDU EDC 00 00 02 90 00 B2 TPDU NAD PCB LEN APDU EDC 00 40 06 A4 00 00 02 3F 00 E2 SELECT FILE FID 3F00 response to SELECT FILE TPDU NAD PCB LEN APDU EDC 00 40 02 90 00 F2 TPDU NAD PCB LEN APDU EDC 00 00 06 A4 00 00 02 3F 00 A2 SELECT FILE FID 3F00 response to SELECT FILE TPDU NAD PCB LEN APDU EDC 00 00 02 90 00 B2 Figure Successful transmission of a TPDU using the T 1 transmission protocol. The XOR option is used for the error detection code EDC . A SELECT FILE command with a FID of 3F00 which selects the MF is transmitted in the APDU. The incrementing of the send sequence count in the PCB byte for each transaction and the corresponding changes in the EDC can be readily seen used. The elaborate error correction mechanisms are a typical example. Although they may be theoretically interesting in many cases they are ineffective in dealing with actual transmission errors. In practice it is usually better to simply reinsert the card in the terminal and start a new session rather than using innumerable resynchronization requests to attempt to restabilize communications. Consequently the EMV specification imposes several restrictions relative to the original ISO IEC standard as summarized in Table . The T 14 transmission protocol Germany The ISO IEC 7816-3 standard includes a tag in the ATR for designating a national transmission protocol. Such a transmission protocol is designated T 14. With the introduction of the C-Netz for mobile telephony and card phones in Germany a protocol was needed for communicating with the smart cards used in these systems. The character-oriented T 0 protocol was considered undesirable and at that time there was not yet a standardized block-oriented protocol. Consequently in 1987 Telekom decided to use a protocol developed by a DIN working group. This .