I expect that if you ran a query using UDFs to try to read a property from the blob it either wouldn't find the property at all or would give you the encryped value.
You could try something like this. The value in the first parameter is the string name of the property that you are looking for. Case is important. Since every blob should have a pxObjClass property that is one that should work for what you want, adjusting the table name and pzInskey value in the where clause as needed.
select pr_read_from_stream('pxObjClass',pzinskey,pzpvstream) from pc_work where pzinskey = 'PEGASAMPLE C-1';
What will be my dynamic sysem setting for enabling encryption, suppose my class for encryption is com.pega.pegarules.crypto.PRCipherSampleBF,then the setting is crypto.sitecipherclass and com.pega.pegarules.crypto.PRCipherSampleBF in Pega-Engine Ruleset ?
P.S Steps followed to enable encryption
1. Used RunPega Utility to run the List the supported Cipher
2. Used RunPega Utility to Create Cipher[Got the Java code]
3. Used CompileandLoad Utility to load the java code generated [By Replacing the class name and package name com.pega.pegarules.crypto.PRCipherSampleBF]
4. Created DSS setting specified above.
5. Restarted the 2 nodes out of the 4 nodes.
6. Clicked on Encrypt Blob on the Class, and performed a commint on the work object of that class.
As you can see in this article under the section "Updating the prconfig.xml file to refer to the new cipher class" you can see the prconfig setting that is needed to specify what the cipher class to use is.
While most prconfig settings can be specified as DSS instead I am not sure if this particular prconfig setting is one that can be specified as a DSS. Refer to this article for how to set prconfig values as DSS.