Is it possible to use process.hrtime in Node-RED to measure an algorithm’s decryption time in microseconds?
Yes.
Depends.
It depends on how that algorithm is being run. If in a function node, then certainly you can. If between nodes in a flow, you still could but I don't know how meaningful it would be due to other overheads.
In a function node, simply "install" node:process in the function node's "Setup" tab with the name process. You can then simply use process.hrtime in your function code.
