Subject: Questions on the use case of KeyUsage type in Key Usage extension

From: "Jonghyun Baek" <[email-masked]>
Date: Wed, 14 Feb 2007 14:47:24 +0900

Dear PKIX WG,

The key usage extension(section 4.2.1.3 in RFC3280)  have nine KeyUsage types such as digitalSignature, non repudiation, keyEncipherment, etc.
I can understood each of the KeyUsage types meaning but i would like to know a real example or a use case of the encipherOnly type and the decipherOnly type. i mean which kind of the service or application need the encipherOnly or decipherOnly type certificate and for what ?
I will be so appriciate if you give me a hand.

Thanks!

Jonghyun Baek 

=================================================== 
Jonghyun Baek 
--------------------------------------------------- 
Senior Researcher
Electronic Transaction Security Planning Team
Korea Information Security Agency (KISA) 
--------------------------------------------------- 
78 Garak-Dong, Songpa-Gu, Seoul, Korea 138-803 
Tel : +82-2-405-5423  
Fax : +82-2-405-5219 
Mobile : +82-16-591-3664 
E-mail : [email-masked] 
===================================================

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From: Stephen Kent <[email-masked]>
Date: Wed, 14 Feb 2007 07:11:13 -0500

At 2:47 PM +0900 2/14/07, Jonghyun Baek wrote:
>Dear PKIX WG,
>
>The key usage extension(section 4.2.1.3 in RFC3280)  have nine 
>KeyUsage types such as digitalSignature, non repudiation, 
>keyEncipherment, etc.
>I can understood each of the KeyUsage types meaning but i would like 
>to know a real example or a use case of the encipherOnly type and 
>the decipherOnly type. i mean which kind of the service or 
>application need the encipherOnly or decipherOnly type certificate 
>and for what ?

The typical example that has been provided (by others) is a multicast 
application where one wants to enforce encrypt/decrypt only key use 
for subscribers, e.g., most subscribers are authorized to listen 
(decrypt) and only one or a few are authorized to send (encrypt).

Steve

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From: Russ Housley <[email-masked]>
Date: Wed, 14 Feb 2007 14:33:37 -0500

Jonghyun Baek:

The encipherOnly and decipherOnly were specified to support a form of key
escrow that was developed at Royal Holloway.  To the best of my
knowledge, no one is using that key escrow system today.

Russ

Dear PKIX WG,

The key usage extension(section 4.2.1.3 in RFC3280)
have nine KeyUsage types such as digitalSignature, non repudiation,
keyEncipherment, etc.

I can understood each of the KeyUsage types meaning but i would like to
know a real example or a use case of the encipherOnly type and the
decipherOnly type. i mean which kind of the service or application need
the encipherOnly or decipherOnly type certificate and for what ?

Thanks!

Jonghyun Baek

Jonghyun Baek

Senior Researcher

Tel : +82-2-405-5423

Fax : +82-2-405-5219

Mobile : +82-16-591-3664