The first line of PCK.ITPA_SHARED.PRV.INCLUDE.DECRYPT_PASSWORD is below:
:SET &DECRYPT_COMMAND# = 'java -jar "&$AGENT_RESOURCES_CLIENT#itpa-tool.jar" ARB -cmd cipher decrypt "&UC4RB_ENCRYPTED_PASSWORD_TMP#"'
Where to get itpa-tool.jar?
Release : 12.2
Component : AUTOMATION ENGINE
The itpa-tool.jar is a resource file of this ITPA_SHARED pack,
It is saved as a resource file in the store object PCK.ITPA_SHARED.PRV.STORE, only when the job is executed, this file will be attached to agent's resource directory.
You don't have to download or get it manually from anywhere, it is loaded along with the store object when the package was installed.