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3

You can do either. Though make sure you tighten up how you do the first scheme. In the first case you are going to have multiple tags, 1 for each chunk. In the latter, you will have a single tag. If you are downloading files that are approximately 1MB, I think #2 makes sense. If you are downloading files that are 1GB or 1TB, maybe #1 makes the most sense, ...


0

The latest version (1.6) can be found on http://www.gsma.com or http://dacas.iie.cas.cn/. Direct links: Specification of the 3GPP Confidentiality and Integrity Algorithms 128-EEA3 & 128-EIA3. Document 2: ZUC Specification (pdf) on gsma.com ZUC算法文档v1.6 (zip) on dacas.iie.cas.cn (contains a bit more information such as more test vectors)


2

There is no such thing as 64 bit triple DES. Well, to be more precise, there is, but it is fully equivalent to single DES. If the first block decrypts and the rest doesn't then you're probably using the wrong mode of operation. Try a few others such as DES in CBC mode or CTR mode using a zero valued IV.


0

Your algorithm is vulnerabel to brute force attacks. XOR the ciphertext with parts of the PI fraction starting with n and then with n+1 and so on. Today's fast computers won't take long to crack it. :)


4

The definitions are not all universal and there is quite some overlap. The clearest definition is for PRG, which is the (synchronous) stream cipher model. A PRG maps a secret value to a long, random-looking keystream, so that an attacker cannot predict any part of the keystream from knowing other parts of it. For a precise definition, you can see the ...



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