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Questions tagged [cbc-mac]

Cipher Block Chaining MAC (CBC-MAC) is a method of building a message authentication code from a block-cipher.

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Does length prepending fix the key reuse problems with CBC and CBC-MAC?

As I hope everybody is well-aware, re-using the key for CBC-MAC and CBC is a really bad idea. Now, there's also the paradigm to prepend the message length to the CBC-MAC (as "associated data") to ...
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Authenticated Encryption CCM encrypt MAC

Suppose I have Encryption in CTR-Mode and a CBC-MAC. Why should I also encrypt the MAC? In the documentation of NIST stands: "By encrypting T we avoid CBC-MAC collision attacks". But I can not ...
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Modify basic CBC-MAC construction using a keyed function

Typically, CBC-MAC is a secure MAC for fixed length message if the construction uses a pseudorandom function. However, for a secure MAC, we can use a keyed function that is not necessarily ...
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Create MAC and IV given known IV and MAC for previous message

I've been given a AES-CBC-MAC, a message and the IV. I don't know the key. Given a second message I am supposed to derive the IV and create a valid MAC. I believe I've successfully created the ...
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CBC MAC and DES combined question?

Suppose that we want to develop a MAC scheme which is as secure as Triple-DES CBC-MAC and at the same time as efficient as Single-DES CBC-MAC. We come up with the following idea: Except the last ...
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how to use CBC-MAC to ensure both integrity and authentication?

If I used the CBC mode to encrypt and decrypt (n) blocks how can I use CBC-MAC to ensure both integrity and the authentication, I know how to use it for authentication only but what if I want to use ...
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CBC-MAC with a constant key

What affect does having a constant key have on a CBC-MAC algorithm and how would it make the CBC-MAC not pre-image resistant.
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From block-wise Universal Hash Function to bit-wise UHF

Let's assume we have an $\epsilon$-bounded Universal Hash Function Family $H = \{H_K:\mathcal{X}^{\leq m}\rightarrow \mathcal{X}\mid \forall K\in \mathcal{K}\}$ with $\mathcal{X} = \mathcal{K} = \{0,1\...
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NRPAD and FPAD padding schemes (Korean Seed?)

I've got an API spec that specifies NRPAD and FPAD as possible padding schemes. I see these being used together with the Korean SEED algorithm. The SEED specification however is void of any padding ...