# Re: QC-proof cipher?

*From*: Peter Fairbrother <zenadsl6186@xxxxxxxxx>*Date*: Tue, 23 May 2006 21:47:52 +0100

Paul Rubin wrote:

Peter Fairbrother <zenadsl6186@xxxxxxxxx> writes:

Does anyone know of a secure symmetric cipher which is known to be

resistant to quantum computation techniques?

"Known"? There isn't even a symmetric cipher "known" to be resistant

to conventional computation techniques, let alone quantum computing.

I realise that. Perhaps I misspoke. If we want to be picky, there is only

one "secure" symmetric cipher too, OTP.

What are you really asking?

Isn't it obvious? I'm looking for a symmetric cipher (or even a hash)

designed with resistance to QC in mind.

I'd like a reasonable level of assurance. AES level would be good but almost

certainly not available, even hasty-pudding-level would be good - but

designed under the assumption that qc's are available to the attacker.

I'm preferably looking for something around 512 bits key and 512 bits block

size, for long-term future-proofing.

I'm not getting into the question of whether QC's will exist, or when, just

whether anyone has designed a half-decent or better cipher with resistance

to QC techniques in mind.

--

Peter Fairbrother

.

**Follow-Ups**:**Re: QC-proof cipher?***From:*laura fairhead

**Re: QC-proof cipher?***From:*John Savard

**Re: QC-proof cipher?***From:*Paul Rubin

**References**:**QC-proof cipher?***From:*Peter Fairbrother

**Re: QC-proof cipher?***From:*Paul Rubin

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