Security, spreadsheet

Whenever a standard calculation has to be repeated over a long period of time, the generation of a validated spreadsheet should be considered. Validation of spreadsheets can be time- and resource-intensive. Therefore, it has to be decided if a validated Excel spreadsheet is the solution of choice. Beside the actual validation of each spreadsheet, a procedure has to be established to handle and work with the spreadsheet. GXP-related questions to address include the use of secure data storage locations, missing ER/ES compliance, and audit trail in Excel. These areas are as important as the validation itself and will require resources. 

The primary focus during validation is validation of the content of the spreadsheet itself. Nevertheless, items such as location of storage, security of cells and file, as well as access to the file have to be taken into account. The general validation approach for spreadsheets is not different from other validation approaches and can be arranged in three general sections (1) validation plan, (2) execution of the plan, and (3) validation documentation (protocol). 

The requirement section has to describe the requirements of the spreadsheet clearly. The requirements have to be chosen in a manner that permits tests to be developed and performed to check if the spreadsheet fulfills its functions. For each requirement a corresponding test should be performed. The requirement section will include information about purpose, functional, performance, security, and design requirements. 

This section of the validation plan should describe the expected function and security of the spreadsheet. The requirements should be formulated in a manner... 

Note The spreadsheet should be stored in a secure place after development and prior to validation to avoid unauthorized changes during and after validation. The folder should contain only spreadsheets that are currently under validation. When the validation is performed successfully, the file should be moved to a different secure folder. This movement has to be documented. 

Saving the (master) spreadsheet only on secure drives where only authorized people have access... 

The security strategy selected has to ensure that cells containing formulas (on purpose, by mistake, or by the auto-save function) of the spreadsheet cannot be overwritten. In today s standard office network environment, in some cases, the network itself is, not validated and does not fulfill the electronic record/electro-nic signature requirement. Therefore, the validated spreadsheets should be stored in a protected drive to which only restricted personnel have access. Furthermore, the server used for storage/handling should be qualified. Figure 18.7 is an example. 

The training description will include information about purpose, responsibilities, training deliverables, and training records. In some cases it will require generation of a document explaining the use of the spreadsheet. In this document, the function of the spreadsheet, the formulae used, the location of the secure templates, and the file name and path to use to save the completed form should be included. Training has to be documented. Figure 18.8 is an example. 

Electronic record/electronic signature. Currently, requirements concerning ER/ES according to FDA 21 CFR Part 11 cannot be implemented with Excel spreadsheets. Concerns include file protection, security, user access, audit trail, version retention, file deletion or erasure, electronic signature(s), and network issues. These can be resolved using a hybrid system, an electronic version of the spreadsheet and an approved hard copy. After data entry (and subsequent to... 

Security as a topic is referred to the same number of times as backup and archive. Security issues raised stress the need to limit access to computer systems to protect records, and in one instance deficient password controls are mentioned. Computer systems referred to include CDS, CAD, Record Keeping Systems, and Spreadsheets. 

Some researchers, of medical scientists or biostatisticians, have maintained that the same record could be used for all purposes it is merely a matter of what the researcher is allowed to access. There seems to be a general feeling that an ARC should be a distinct archive outside the security firewall, with the identified records held inside. Moreover there are subtleties in statistics that allow certain statistical overviews to nail down detailed data. For example, if a spreadsheet, contains multidimensional data with only averages in the rows and columns, it should not be possible for anyone to work back from the marginal summaries to deduce the interior of the spreadsheet. But in fact a mathematical algorithm is already known to medicine that allows medical images to be constructed—tomography. 

Standard Operating Procedures (SOPs), inciuding security practice and backup and restoration Use of spreadsheets... 

With respect to computation, for limited numbers of assets (small /), solutions are easily obtained (although not necessarily efficiently) using standard spreadsheet optimizers. This works for the vast majority of allocation problems because most applications typically include no more than a dozen assets. More specialized optimizers are sometimes necessary when there are many assets. For example, if MV is applied to select a stock portfolio, there may be hundreds of securities used as admissible assets. ... 

Depending on the version of EXCEL being used, the procedures to activate Macro Code differ. In EXCEL 97, when the spreadsheet is loaded, the user is asked whether macros should be enabled. An affirmative response is necessary, after which EXCEL loads the complete file, which contains many worksheets most of which are hidden. In EXCEL 2000, and later versions, three security settings under the Tool, Macros menu are offered. The highest setting does not allow VBA code to be opened. 

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