transientMap in node.js and getTransient in chaincode

Question

Can somebody explain the usage of transientMap in channel.sendTransactionProposal(request, timeout) and getTransient() in chaincode with an use case. What is so special with data of getTransient() when compared to normal arguments

Answer 1

Regular arguments are a part of the endorsement proposal and therefore persisted even when the transient map is not. 

For this reason, if you would like to pass some data which is not required to be kept in the endorsement proposal, use GetTransient API. 

For example, while doing application-level encryption, pass the keys and crypto material within the transient map itself.