[146743] in cryptography@c2.net mail archive
Re: [Cryptography] Why prefer symmetric crypto over public key
daemon@ATHENA.MIT.EDU (Naif M. Otaibi)
Sat Sep 7 14:53:00 2013
X-Original-To: cryptography@metzdowd.com
In-Reply-To: <AC356128-00B0-481A-BD0D-BBB2EC0225D4@cs.ru.nl>
Date: Sat, 7 Sep 2013 21:28:35 +0300
From: "Naif M. Otaibi" <otaibinm@gmail.com>
To: Jaap-Henk Hoepman <jhh@cs.ru.nl>
Cc: Crypto <cryptography@metzdowd.com>, Jon Callas <jon@callas.org>
Errors-To: cryptography-bounces+crypto.discuss=bloom-picayune.mit.edu@metzdowd.com
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it boils down to this: symmetric crypto is much faster than asymmetric
crypto. Asymmetric crypto should only be used to exchange symmetric keys
and signing.
On Sat, Sep 7, 2013 at 11:10 AM, Jaap-Henk Hoepman <jhh@cs.ru.nl> wrote:
>
> > I have also, in debate with Jerry, opined that public-key cryptography
> is a powerful thing that can't be replaced with symmetric-key cryptography.
> That's something that I firmly believe. At its most fundamental, public-key
> crypto allows one to encrypt something to someone whom one does not have a
> prior security relationship with. That is powerful beyond words.
>
> I share that belief. Hence my desire to fully understand Bruce's remark.
>
> Strictly speaking you need some kind of security relationship: you need to
> be sure the public key belongs to the intended recipient (and is under his
> sole control). So public key crypto allows you to bootstrap from some
> authentic piece of information (public key belongs to X) to a confidential
> communication channel (with X).
>
> Jaap-Henk
> _______________________________________________
> The cryptography mailing list
> cryptography@metzdowd.com
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>
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<div dir=3D"ltr">it boils down to this: symmetric crypto is much faster tha=
n asymmetric crypto. Asymmetric crypto should only be used to exchange symm=
etric keys and signing.</div><div class=3D"gmail_extra"><br><br><div class=
=3D"gmail_quote">
On Sat, Sep 7, 2013 at 11:10 AM, Jaap-Henk Hoepman <span dir=3D"ltr"><<a=
href=3D"mailto:jhh@cs.ru.nl" target=3D"_blank">jhh@cs.ru.nl</a>></span>=
wrote:<br><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;bor=
der-left:1px #ccc solid;padding-left:1ex">
<div class=3D"im"><br>
> I have also, in debate with Jerry, opined that public-key cryptography=
is a powerful thing that can't be replaced with symmetric-key cryptogr=
aphy. That's something that I firmly believe. At its most fundamental, =
public-key crypto allows one to encrypt something to someone whom one does =
not have a prior security relationship with. That is powerful beyond words.=
<br>
<br>
</div>I share that belief. Hence my desire to fully understand Bruce's =
remark.<br>
<br>
Strictly speaking you need some kind of security relationship: you need to =
be sure the public key belongs to the intended recipient (and is under his =
sole control). So public key crypto allows you to bootstrap from some authe=
ntic piece of information (public key belongs to X) to a confidential commu=
nication channel (with X).<br>
<span class=3D"HOEnZb"><font color=3D"#888888"><br>
Jaap-Henk<br>
</font></span><div class=3D"HOEnZb"><div class=3D"h5">_____________________=
__________________________<br>
The cryptography mailing list<br>
<a href=3D"mailto:cryptography@metzdowd.com">cryptography@metzdowd.com</a><=
br>
<a href=3D"http://www.metzdowd.com/mailman/listinfo/cryptography" target=3D=
"_blank">http://www.metzdowd.com/mailman/listinfo/cryptography</a><br>
</div></div></blockquote></div><br></div>
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