Problems with Cryptography and Real World Examples

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RESPONSE:

1. List 4 problems dealt with by cryptography & give real world examples of each. (2 paragraphs please.)

Cryptography is used to solve the following problems related to securing communications:

1. Confidentiality, also known as secrecy (click on underlined words for more detail if required):: For example, only an authorised recipient should be able to extract the contents of the message from its encrypted form. Otherwise, it should not be possible to obtain any significant information about the message contents.

2. Integrity: For example, the recipient should be able to determine if the message has been altered during transmission.

3. Authentication: For example, the recipient should be able to identify the sender, and verify that the purported sender actually did send the message.

4. Non-repudiation: For example, the sender should not be able to deny sending the message.

5. Anti-replay: For example, the message should not be allowed to be sent multiple times to the recipient without the
sender knowing.

6. Proof of delivery: For example, the sender should be able to proove the recipient received the message.

Cryptography can provide mechanisms to help achieve all of the above. However, some goals are not always necessary, practical or even desirable in some contexts. For example, the sender of a message may wish to remain anonymous; clearly non-repudiation would be inappropriate in that case (http://en.wikipedia.org/wiki/Cryptography#Other_topics).

EXTRA INFORMATION FOR CONSIDERATION:

More on Security: Cryptography prevents attacks

Hackers and attackers can "crack the code" and break into systems for information in this way. For example, the goal of cryptanalysis is to find some weaknesses or insecurity in a cryptographic scheme. Cryptanalysis might be undertaken by a hostile attacker, attempting to subvert a system; or by the system's designer (or others) wishing to evaluate whether a system is secure. There are a wide variety of cryptanalytic attacks, and they can be classified in several ways. One distinction concerns what an attacker can know and do in order to learn secret information. For example, does the cryptanalyst have access only to the ciphertext? Does he also ...