I am curious as to whether there is a specific amount of quantum volume that will allow a quantum computer to break a 2048 bit number used in RSA encryption, and if so, what that number is. (within a realistic time frame of less than 1 hour)


  • $\begingroup$ The quantum volume has nothing to do with the time taken. Otherwise: Yes, there is a specific amount. $\endgroup$ Jun 23 at 10:52

To perform integer factorization on a quantum computer sucessfully depends mainly on number of available qubits and their quality (low noise and long decoherence time). Of course, quantum volume is linked to these two parameters.

According to the article this article dissused here, some millions of qubits are necessary to break 2,048 bit RSA key.

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    $\begingroup$ Some million physical or some million logical qubits? The quantum volume should ultimately (asymptotically) measure logical qubits, shouldn't it? $\endgroup$ Jun 24 at 17:19
  • $\begingroup$ @norbert schuch: Logical qubits I suppose as you need to avoid errors caused by decoherence. $\endgroup$ Jun 24 at 18:03
  • $\begingroup$ I don't believe that you need millions of logical qubits to factor a 2000 bit number! Afair storing some number on the order of N^2 should suffice. (I mean, the time must scale as poly(N), and thus also the space. This would have to be a rather high power!) And if it is physical qubits, I don't think this has much to do with quantum volume. $\endgroup$ Jun 24 at 20:25

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