Property rules — Implementing and using the TextEncrypted type

Comparing the Password and TextEncrypted property types

Process Commander offers two Types for sensitive Single Value, Value List and Value Group properties: Password and TextEncrypted. Both types produce encrypted (or hashed) values for the property value within the PegaRULES database, and both types offer some degree of security within the user interface.

When choosing which Type value to use, consider these factors:

• The Password type requires no advanced configuration or Java skills to set up. Several standard properties implement this type; for example, the property Data-Admin-Operator-ID.pyPwdCurrent. Process Commander applies the one-way MD5 message digest algorithm to this value, which is never sent to any external system.
• For best use, the TextEncrypted type requires one-time Java coding of encryption Java functions of your choice to implement a Public API Interface. (A working sample is provided).
• On Process Commander forms, the display of a Password value is either a string of asterisks or the hexadecimal hash value, for all users, in all situations. The Password value is never decrypted. In contrast, the value of a TextEncrypted property can appear in clear text or as asterisks, depending on the runtime outcome of an access when rule (Rule-Access-When rule type). Thus your application can make the clear-text value visible to specific users, or on certain reports, or during specified time periods.
• Password properties are initially added to the clipboard as unencrypted, clear text values. The system computes the hashed value only as the page is committed to the PegaRULES database. Thereafter, the hashed value appears in both the clipboard and the database row.
• TextEncrypted values are always encrypted on the clipboard and in server-to-database network messages.

Implementing the TextEncrypted type

1. Create a Java class that implements the following PublicAPI interface:

com.pega.pegarules.crypto.IPRCipher

Your implementation can start with the working sample, which is based on the Blowfish algorithm:

com.pega.pegarules.crypto.PRCipherSampleBF

However, don't use this sample directly without modification. Using a custom implementation provides your enterprise with greater security, as it makes your site-specific encryption differ from the sample.

2. Update the prconfig.xml file (on each node) to add lines that identify the Java class:

<env name="crypto/sitecipherclass" value="cccc" />
<env name="classloader/classpath" value="dddd" />

where cccc is the class name and dddd identifies the directory containing the class. (You can omit the second line, depending on the class paths of your system.)

3. Redeploy and restart to make the prconfig.xml changes effective.

4. Create one or more properties that use the TextEncrypted type. Complete the General tab:

• Set the Type to TextEncrypted.
• Set the HTML Property field to ShowTextEncryptedPropertyValue.
• In the Access When field, enter the second key part (When Name) of a Rule-Access-When rule that determines whether the property value appears as decrypted clear text or asterisks. The Rule-Access-When rule can depend on any properties in the Applies To class, plus properties on the pxRequestor page or other clipboard pages.

5. Reference the property normally in other rules.

6. Implement the identical prconfig.xml changes and Java class on each server node of a cluster. If you attempt to decrypt a property value but no cipher algorithm is defined on that node, the system records an exception in the Pega log similar to the following:

com.pega.pegarules.pub.context.CryptographicException: decrypt: No site-specific cipher algorithm

Comparisons

You can use a TextEncrypted property in expressions, testing for equality or inequality only. Call the standard function rule encryptPropertyValue() to encrypt the comparison value (a constant, a property value, or computed text value) before the comparison. For example:

@encryptPropertyValue("Virginia") == .myEncryptProperty

.myEncryptProperty != @encryptPropertyValue(.pyLabel)

The access when rule test and automatic encryption (or decryption) occur only as users interact with a form. In all other cases, your application must explicitly call the functions.

Process Commander allows comparisons other than equality or inequality, but results are unpredictable.

Type conversions

Process Commander does not perform any automatic type conversions for TextEncrypted properties during Property-Set operations. As a result, it is rarely useful to directly assign an encrypted value to another property, or assign another property value to a TextEncrypted property.

When a TextEncrypted property is set to a value, the system encrypts the value unless it is already encrypted. For example, in an activity, a Property-Set method operates on two properties MyEncrypted (of type TextEncrypted) and MyText (of type Text).

After the first of these three lines executes, the value in property MyEncrypted is encrypted. After the second line, the value in property MyText matches the value of MyEncrypted; no encryption or decryption takes place. After the third line, MyEncrypted holds the encrypted value from "Rosebud"; encryption is implicit.

Reports

To use a TextEncrypted property as a selection criteria on the Content tab of a list view or summary view rule:

1. Expose the TextEncrypted property a database column.
2. Enter the clear text value (or a property reference for the comparison) in the Value field.
3. Select either Is Equal To or Is Not Equal To for the comparisons.
4. Enter EncryptTextPropertyValue in the Edit Input field.

The rule forms accept comparisons other than Is Equal To or Is Not Equal To, but results are unpredictable.

Services and connectors

If an external system calls a service and sends to Process Commander a (clear text) value for a field that is mapped to a TextEncrypted property, the value becomes encrypted as soon as it reaches the clipboard.

Responses to service calls and connector requests normally send only the encrypted value. Your application can call the standard function @decryptPropertyValue() to send the decrypted, clear text value, but only in a context when the access when rule is true.

Notes

Don't send an encrypted property value to an external system that expects the clear-text value.

On the Clipboard tool display, the value of a TextEncrypted property is blank.

Except as described here, Process Commander treats the value of a TextEncrypted property similar to a Text property. Your application can place dates or numbers in the value, but no validation occurs.

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	About Access When rules

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