Encryption Algorithm

Hello,

I am using RsLogix 500 and have my system already programmed in Ladder Logic. I am trying to add a step where I use an encryption algorithm to encrypt data being sent to and from the system, but how can I add a step that uses a coded algorithm into the ladder logic?

Thanks

Logiks5,

I have to ask, why would you want to do such a thing?
Yes, it can be done, but, all you are doing is making the program more complicated, slowing down the process scan time, having to write the encryption / decryption routines, and making the program hard to debug / modify, and writing code that only you can understand. A company could interpet this as writing code for job security. You may have a good reason for doing this, but i know of several people who have been escorted out the front door for writing such code. it cost their companies over a million dollars and now those companies (and those individuals) are required to sign legal documents assuming liability for any such code in the future.

Not trying to slam you, just expressing my opinion, because i'm the one who has to trouble shoot that code, report the problem, document the problem, answer to the department head, show him what's happening & why production was down for so long (or still is down). it gets real messy and pretty soon, the plant manager will be involved and possibly the legal department to see what can be done now and in the future.

regards,
james

James Mcqade:

Thank you for your concern for my job. I am working on a simple system, and testing methods to protect it from cyber attacks, and since it is experimental, there would not be any consequences for attempting encryption. However, I do appreciate the information.

Do you have any recommendation on how to implement encryption? I read about other programs using defined function blocks, or converting rslogix5000 to ST and coding in that. However, I am restricted to using RsLogix 500.

I don't think you will be able to accomplish the task at hand when working with a 40 year old platform.
IMHO the only way you could prevent SLC/ML systems unwanted intrusions is by using the built-in access/file/data transfer security functions depending of the system's controller class.

Encryption is very computationally expensive and PLCs shouldn't be doing such things without some sort of coprocessor or hardware chip. The math would be messy in ladder. I would at least use a process that can be programmed with structured text.

That's sort of my question, assuming I have an encryption algorithm coded in Structured text, is there a way for me to integrate that code into my already existing ladder logic program?

Not on a Logix500 platform.
The only RA/Allen-Bradley system supporting STL is Logix5000.

Maybe a Basic module 1746-BAS.

http://literature.rockwellautomatio...-bas&passedType=Full&passedParameter=1746-bas

unlock rslogix500

hi
its a hex password of AB plc rslogix500
79 24 53 21 50 0C 7B 28 59
and my password is
BBBBBBBBBB = 42 42 42 42 42 42 42 42 42 42
whats the algorithm??
can you help me?
i have a lock plc and i test this,i cant find the algorithm between them.
thanks
anahita