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KAMSPioneer t1_j1noanj wrote

Reply to comment by StinkiePhish in An IBM Quantum Computer Will Soon Pass the 1,000-Qubit Mark by giuliomagnifico

Totally. Just to be clear for the thread, a useful quantum computer will break ECC way, way before AES or SHA2.

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pm_me_wet_kittehs t1_j1qg1oa wrote

for symmetric algorithms, a quantum computer would turn 256 bits of security into the equivalent of "Only" 128 bits. Double the key length amd any advantage just goes up in smoke. quantum won't help in a practical manner for AES

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maqp2 t1_j1tmb9l wrote

Also, SHA256 does lossy compression, and obtaining preimages larger than 256 bits can not be done at all, QC or not.

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