Both Crypto View system and COALA system are OK as they make the students answer questions concerning the visualization presented by the system, and enable them to control the execution of algorithms forward and backward, and to configure the algorithm parameters before starting an execution, which make it possible for them to follow the result of every operation in any time. Both Crypto system and COALA system include AES, DES, RSA, Diffie-helman,Vigenere cipher, Symmetro-Asymmetro Algorithms.
Thank you Hadeel, looking at these link: https://cps-vo.org/node/19921 and reading Article COALA - System for Visual Representationof Cryptography Algorithms
it is great that visualization of these concept is at the learner fingertip.