VeriFone DUET Vx810, Справочное руководство

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F
ILE
A
UTHENTICATION
File Authentication and the File System
84
V X 810 R
EFERENCE
G
UIDE
If the signature file authenticates its target file and the *FA variable is present in
the config.sys file of the target file group and is set to 0, the signature file is erased
when its target file is authenticated.
If you intend to perform back-to-back downloads, as described in Chapter 6 , all
signature files must be retained in the V
x
810’s application memory, together with
the target application files they authenticate.
Restrictions on Downloading Different File Types
A typical application download includes a variety of different file types. The
following restrictions describe how you can download different kinds of files to the
V
x
810 and how files are stored in its file system:
The normal size of a signature file is approximately 400 bytes. Depending on the
application’s size and on how memory space is allocated, the area available for
storing multiple signature files must be carefully managed. The memory space
required by a certificate file is also approximately 400 bytes, but certificate files
are temporary. When a certificate is authenticated, the data it contains is copied to
the certificate tree, and the certificate file is erased from the target file group’s
SRAM.
NOTE
Normally signature files are retained in the device even after being used to
authenticate executable (code) or data files. This is to facilitate back-to-back
downloads, as described in
Chapter 6 . Users who do not intend to perform
back-to-back downloads can remove signature files after use, gaining space for
other files. Automatic removal is performed if the user sets *FA=0 in the
config.sys file of Group 1. The main reason for using *FA is to force automatic
removal. If the user desires the default behavior (retain signature files, to allow
for back-to-back downloads), the user does not need to set *FA.
NOTE
To control if signature files are retained or deleted when they are processed by
the file authentication module, you must use the protected config.sys variable
*FA as documented in the Verix V Operating System Programmers Manual.
Table 14 Download File Extensions
File Type Restriction
Certificate (*.crt) Must be downloaded onto the SRAM of the target file group
(GID1–GID15) selected in system mode.
Signature (*.p7s) Must be downloaded onto the SRAM of the target file group
(GID1–GID15) selected in system mode.
Operating system Must be downloaded onto Group 1 SRAM. When the OS files,
related certificates and signature files are authenticated, they are
automatically moved from Group 1 SRAM into the Group 0 sub-
partition reserved for the operating system.