11- What are the main techniques on which secure systems? 12- How does modern cryptography work? 13- In a group of users who cooperate directly share resources such as documents in a small, closed...

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Extracted text: 11- What are the main techniques on which secure systems? 12- How does modern cryptography work? 13- In a group of users who cooperate directly share resources such as documents in a small, closed group. 14- When the client sends a request for an operation to be carried out, we say that the client .... .... 15- What is mobile code?