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14 votes
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Is SipHash cryptographically secure?

A fast 64-bit hash cannot be completely secure, since a $2^{32}$ brute force collision search is completely doable, and even a $2^{64}$ preimage attack could be feasible. As a MAC used for hash table ...
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7 votes

Is SipHash cryptographically secure?

This may just be a matter of terminology. A claim that an algorithm is "secure" is meaningless without qualifying/quantifying what it is secure against. Conventionally, the security/strength ...
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5 votes
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Generate a unique 64 bit numeric database key without collisions at $2^{32}$ birthday threshold?

Unfortunately, without some additional assumptions about the strings (e.g. that the first 8 bytes are unique), there is no way to reduce the chance of collision below the usual chance levels. If you ...
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  • 360
5 votes

Same 64-bit preimage resistance security for SipHash and SHA-512/64?

SipHash doesn't claim to be a secure hash function. Only a secure MAC. So if you try to use it as a hash function, with a constant, public key, you are on your own. SHA-512/64 should be a "secure" 64-...
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4 votes

Does SipHash have 64 bit (second) preimage security?

SipHash is a MAC (aka Pseudo Random Function Family) with 64-bit output and 128-bit key, rather than a hash (aka random public member of a Pseudo Random Function Family). It is explicitly designed to ...
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3 votes
Accepted

A fast non-cryptographic hash function that is "strong enough"?

So what you need is a fast cryptgraphically secure hash function? There are some. If you're in hardware Keccak might be an option as it uses many bit-permutations. If you're in software there are ...
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2 votes
Accepted

SipHash's (non-)collision resistance

It is not collision-resistant because the tag is only 64 bits, so on average only $2^{32}$ inputs are needed to find a collision. This is the classic birthday bound. This is completely insecure, so ...
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  • 4,643
2 votes
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Cryptanalysis of Marvin32 compared to SipHash

It isn't a good cryptographical PRF (and, to be fair to the inventor, he never claimed it was). Marvin32 starts with a secret state, and processing the message and the state to give a new state, and ...
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2 votes

Same 64-bit preimage resistance security for SipHash and SHA-512/64?

A quick resarch showed that there are no (good) attacks on Siphash. For SHA-512 there are defintely no known attacks. The first 64 bits of SHA-512 should have the same security guarantees as full SHA-...
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1 vote

Cryptanalysis of Marvin32 compared to SipHash

Looks like Marvin32 is a part of a patent :-) And Microsoft really do believe it is resistant to Hash Flood attack. http://www.google.com/patents/US20130262421
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1 vote

Generate a unique 64 bit numeric database key without collisions at $2^{32}$ birthday threshold?

However, if instead you truncated the hash to (64 bits - X bits), and concatenated the resulting hash with the first X bits of the input string, you'd reduce the chance of collision since two similar ...
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