VeriFone VX 520 Specifications download pdf (Page 92)

FILE AUTHENTICATION

File Authentication and the File System

92 VX 520 REFERENCE GUIDE

application is usually the main application stored in Group 1 and called from

the *GO variable in the CONFIG.SYS file in GID1.

• The main application stored in GID1 can access files, secondary applications,

or function libraries stored in any other file group.

• The application downloaded into GID1 is always the primary application for

the terminal. This application is owned by the primary terminal sponsor

(sponsor A) in cases where there are multiple sponsors.

• The Group 1 application controls any and all secondary applications stored in

terminal memory. That is, a secondary application can only be invoked by a

RUN command issued by the Group 1 application.

• An application stored in Groups 2–15 can only access files stored in its own

file group and in Group 15. For example, an application authorized by the

sponsor to be authenticated in Group 4 can only access files and libraries

stored in Group 4 and Group 15.

• If multiple applications (main and secondary) are to run on the same terminal,

each .OUT and/or shared library file must have its own matching signature file.

Because each application is responsible for verifying its own data and prompt

files, the other application files should have their own matching signature files.

The master .OUT file should validate that these additional signature files are

authenticated before they are used.

• If two or more applications will run on the same terminal, the signature files for

the respective applications must be downloaded, together with the

corresponding target files, into the specific file group(s) for which the

applications are authorized. If an application is downloaded into a group for

which is it not authorized, file authentication for that application fails.

If, for example, Application B is downloaded into GID4, where it is authorized

to run, but the signature files for all Application B executable files are

downloaded into GID7, file authentication for Application B fails and it is not

allowed to run.

• Each certificate contains an attribute to verify if an application is valid for a

particular group.

Authenticate Files Stored in the RAM or Flash of a File Group

All *.p7s files are loaded into RAM and contain flags that indicate if the file to

verify is stored in flash or RAM. A signature file must know if its matching

application file is stored in flash or RAM. If a signature file cannot locate its

matching application file, the application file is not authenticated.

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VeriFone VX 520 Specifications Page 92