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I am not the best cryptologer and therefore I have some questions so I learn more and get better. Heres the questions:

What is Initialization vector (IV)? MUST I use it or not?

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closed as too broad by DrLecter, hunter, Henrick Hellström, Gilles, yyyyyyy Dec 27 '14 at 13:25

There are either too many possible answers, or good answers would be too long for this format. Please add details to narrow the answer set or to isolate an issue that can be answered in a few paragraphs.If this question can be reworded to fit the rules in the help center, please edit the question.

What about reading about these things on your own (e.g. starting on wiki) and then coming back with more focused questions? This is too broad and shows no prior research. – DrLecter Dec 26 '14 at 11:02
Check the question again, I edited it. – tor Dec 26 '14 at 11:09
What part of the Wikipedia article don't you understand? – Gilles Dec 26 '14 at 19:13
@Gilles These sorts of attacks on perfectly reasonable beginner questions need to stop. One of the reasons why the world is as insecure as it is is that people in the industry become hostile to anyone just starting out. If this community is going to be helpful, it needs to accept questions of all skill levels, not just the extremely advanced ones that seem to be currently common. – Steve Sether Dec 29 '14 at 6:01
@SteveSether This is not an attack and not a matter of skill level. Basic questions are fine. But “what is X?” when X can be looked up in an reference which is obviously discoverable, easily accessed and known to be reliable is at best a waste of time to copy the article from said reference. Questions like “I read the Wikipedia article and I don't understand this point: …” are perfectly fine, no matter how basic they are. – Gilles Dec 29 '14 at 12:02
up vote -1 down vote accepted

Check Block Cipher Modes of Operation. IV is required for modes other than ECB, or your encryption will be extremely insecure. (Also note that ECB is insecure itself.)

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This is a very good answer! Thanks – tor Dec 26 '14 at 17:44
Hey the down-voter, could you explain why you down-voted this answer? I could understand why this question is voted down, since it seems too basic. But IMHO, this answer gave a reference to where to check exactly (since it's a basic question, a reference is enough and more informative than a short explanation) and a short answer to the questioner's last question, so I don't think I deserve a down-vote. – Haochen Xie Dec 27 '14 at 7:24
Thanks. Hope this answer has helped you. – Haochen Xie Dec 27 '14 at 8:52
Hi Haochen, welcome to Cryptography Stack Exchange. We (at Stack Exchange in general) prefer answers with a bit more explanation in the answer itself, instead of mainly a link to somewhere else on the Internet. If you could add some sentences about the function of the IV, this would improve your answer. – Paŭlo Ebermann Dec 27 '14 at 12:09
Thank you @PaŭloEbermann. I'll remember that. I was trying to choose among just giving a few sentences about what IV is, to copy and paste a large part of text from another source explaining the cipher mode, and IV (a lot of information is required in order to understand what IV does, and why it's needed), or just give an informative reference, so the questioner could check for good. The questioner is very likely already knowing what IV is, but asking further information, so I provided a link, and answered the last question directly. Well, I'll try to be more informative the next time. – Haochen Xie Dec 27 '14 at 12:32

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