I am doing a security review on a system.

From one part of the system to another, information is sent using an encrypted string.

This string is over 400 characters long, but within it are 4 sets of 10 identical characters. I am assuming that the data that was encrypted also has this pattern, for example the word "parameters".

I have tested encrypting a string containing several identical strings with DES, but do not get the same pattern.

Question is: Is there an encryption method that would produce this result. Or have the parts been encrypted seperatly and conncatinated?