Post-Quantum Cryptography: Q&A with Jean-Philippe Aumasson
+ While quantum computing is still in its infancy, post-quantum cryptography is a field of growing interest for companies and research institutions. InfoQ has spoken with cryptography researcher Jean-Philippe Aumasson to understand where post-quantum crypto is headed.
InfoQ: How real is the threat to current cryptographic systems from quantum computing? Is the possibility that quantum computers break current ciphers “just around the corner”? Do we need post-quantum cryptography today?
Aumasson: There is little chance that we’ll see a quantum computer capable of breaking crypto in our lifetime, but the chance is not zero.
Post-quantum cryptography algorithms are alternative algorithms that could replace elliptic-curve cryptography and RSA, but be safe against quantum computers. Choosing to use these is thus a kind of insurance against the quantum computer risk.
However, in many cases today I believe that adopting these now is premature, because of the following reasons: we still don’t have established standards, interoperability would be a problem, and we don’t have enough mature, production-ready implementations.
InfoQ: What major families of post-quantum crypto algorithms are being currently proposed or investigated?
Aumasson: There are essentially five classes of post-quantum algorithms: 1) Those based on hash functions, such as BLAKE2 or SHA-3; 2) those based on error-correcting codes, which like hash-based crypto were discovered in the 1970s; 3) those based on multivariate equations, or equations with unknown variables multiplied and added together; 4) those based on mathematical lattices those based on isogenies, a pretty complex type of cryptography that involves elliptic curves, like a lot of the crypto we use today, but in such a way that it wouldn’t be broken by quantum computers.
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