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1

Before I give my answer, lets first go over the subject of HMAC. Hash-based message authentication code (or HMAC) is a mechanism for calculating a message authentication code involving a hash function in combination with a secret key. This can be used to verify the integrity and authenticity of a a message. Now HMAC authentication guarantees the ...


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The AES competition received 15 candidates, two of which suffered from "academic breaks" (weaknesses that are only theoretical, but still demonstrate that the underlying block cipher is not "optimally secure"). The remaining 13 are, to my knowledge, still unbroken to this day. Therefore, the choice of Rijndael had to be done for reasons other than security. ...


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On software encryption vs hardware encryption, read this comparison on Kingston's website, and your choice may be easy, but this is marketing language. I'm quite sure that Open Source software encryption like GPG is more secure. See this question: Is hardware based disk encryption more secure that software based?. The basic question is: from who do you ...


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That's right, if the attacker modify one or multiple bits of data that encrypted with AES algorithm, it's not possible to decrypt the data on client .


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My understanding of NFC is that, as a standard, it doesn't offer any provision for encryption of data security. This means you'll have to implement security on top of it. So first: the important part: do not try to implement it yourself: You do not have the understanding necessary to design it properly (as demonstrated by your question) Even with proper ...


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At least the block where the attacker does the modification, its information will not be recoverable (you'll recover senseless info, be careful on that also because it may have sense even!), but depending on the block cipher mode it could disturb your decryption in a longer set. No information is released on that, but how you react to this issue may release ...


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You would go through the relatively arduous task of decrypting and re-encrypting data for only one reason: you believe the crypto key has been compromised, but the data have not, or the reverse. If both data and key were compromised. you're toast. No amount of key-changing will save you. If one of key or data were compromised, it might make sense to ...


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Why you do not do the decryption encryption on demand? Not sure if that work for your case, but here is my thoughts. The data originally come to your web application as plain data right? Then you encrypt the data and store it. Let us assume the following scenario Today I upload file "My_Data1.txt" to your server you encrypt it using an AES key named ...


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Encryption keys can have a cryptoperiod after which those keys shouldn't continue to be used for encryption. This may be due to security policies, due to an individual who knows a key component leaving the business, due to suspicion of an encryption key compromise etc. Often, a business will use an encryption key (let's call this keyA) for encryption for X ...


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Yes, the (unencrypted) contents of the temp file can be recovered after they are deleted (I don't think 7-Zip overwrites them before removing), so they can be a problem (assuming an attacker can the BitLocker disk, such as having administrative account privileges (not necessarily voluntarily given, it could be through a compromise) to your booted computer). ...


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If you have a good encryption algorithm, it shouldn't matter that you include the encryption key. However, better than storing the password itself you better store a salted hash. Or just a truncated version of it (the basis being that a user error is unlikely to mistype one of the very few colliding passwords, while a brute-force attack would not be able to ...



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