11 questions linked to/from Is HMAC needed for a SHA-3 based MAC?
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### Attacks of the MAC construction $\mathcal{H}(m\mathbin\|k)$ for common hashes $\mathcal{H}$?

Consider a common practically-collision-resistant hash function $\mathcal{H}$ (e.g. SHA-1, SHA-256, SHA-512, RIPEMD-160), perhaps based on the Merkle–Damgård construction as are the first three. We ...
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### Is the HMAC construction really neccessary for a fixed length message?

The HMAC Construction is defined as: Hash( (Key XOR opad) || Hash((Key XOR ipad) || Message) ) This was designed because a simpler construction such as: ...
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### Is there a standard way to use a nonce with HMAC?

Many protocols use HMAC on messages that include a nonce, but they don't seem to do it in a consistent way. For example, in OAuth the nonce is in the middle of an URL-encoded key-value string, like ...
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### Database row level encryption scheme

I am wanting to secure some highly sensitive data in a database. This would mean that the data needs to be encrypted and remain secure for 100 years if it were to fall into adversary hands. I also ...
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### Do we still need HMAC now that SHA3 is here? [duplicate]

In Another look at HMAC from Koblitz and Menezes, they state that HMAC came along because doing h(secret || message) was vulnerable to length extension attacks. But as far as I know, these kind of ...