We need to deny access to the editing of R node or meta node, and put on him the password, like in Excel (you can put a password to edit the sheet). This is necessary to ensure that inexperienced users do not accidentally removed a piece of code in the node and did not violate the system performance.
Thanks a lot
You can Lock/Encrypt metanodes so they cannot be inspected or altered unless you have the password, but enabling this feature requires a KNIME Partner Productivity or Server License.
Now, if all you need is to "hide" the code inside an R snippet node so a casual average user will not be able to see/break it, I can share with you a kind of workarond.
You can save the code to an R source file sitting somewhere and use setwd() and source() inside the R snippet node to run it from that file instead that having it typed inside the node. Works equally well.
This said, if your users are more advanced that the average ones, they will still be able to figure out where the R source file is and read/alter it if they want to.
If you need a bulletproof solution then going with KNIME's commercial extensions mentioned above and using metanode Locking/Encryption is definitely what you should do.
You really helped. Thanks again.