If a mapping needs to use real time data from a database table, then this approach may offer a nice solution. It uses a combination of the standard RFClookup function in combination with a UDF for storing a hash table. The trick is to use a generic ABAP function module that reads data using the input in PI:

RFClookup and Java hashlist

 

Tips to setup key authentication for SFTP (based on SSH protocol). SSH can use key based authentication, which consists of a private key and a public key. The private key needs is known to the client and a public key is installed on the server. Each time the ssh or sftp client connects to the server, it sends a public key to the server. The server can verify that the received public key is signed with the same private key as is the one already installed on the server.