# Tag Info

## Hot answers tagged post-quantum-cryptography

2

Symmetric algorithms are secure post-quantum, only with less bits of security (usually about half). That means you only need to care about the authentication and key exchange parts of the cipher suite. Suites that don't use public key authentication or key exchange, i.e. preshared key suites, are post-quantum secure, but not useful in most usecases. There ...

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That Wikipedia article is full of errors and false claims. Most importantly, FSB has not been proven to be as hard as an NP-complete problem. This is because the syndrome decoding problem is NP-hard in the worst case, but FSB uses random instances of the problem. Indeed, these random instances may be much easier to break than arbitrary instances. There is no ...

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One algorithm that is especially suited to one-use key pars is lamport signatures. Like many (all?) other signature functions, lamport signatures first hash the message to get it down to a size that is more reasonable to sign. For this use case, if you are willing to have $n^{2}$-bit signatures and $2n^{2}$-bit keys (public and private), you can sign a ...

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Properly speaking, forward secrecy is a property of a protocol. The protocol is forward secret if compromise of the long term keys does not allow an attacker to decipher any past communications. (Occasionally a distinction is made between that and perfect forward secrecy, with the latter secure when the attacker also knows e.g. all other session keys.) You ...

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If "it's a fact (not just theory) that quantum computing will break PKI in less then 10-20 years" then "we still use, advise PKI" because there is only a small amount of currently existing evidence for that fact. Specifically, there are known algorithms which can be used for PKI that are not known to be breakable by feasible quantum adversaries.

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