Subject: [Trans] [trans] #105 (rfc6962-bis): Shrink LogID

From: "trans issue tracker" <[email-masked]>
Date: Fri, 21 Aug 2015 14:06:23 -0000

#105: Shrink LogID

 SCTs currently contain...
     struct {
         opaque key_id[HASH_SIZE];
     } LogID;

 That's 32 bytes (assuming SHA-256) just to give clients a hint about which
 log public key should be used to verify the SCT signature.  Wasteful.

 Also, I don't see why it needs to be a "struct".

 There are various schemes we could use, but here's my proposal...

 1. Redefine LogID to...
     opaque LogID<1..2^8-1>;

 2. Change...
    '"key_id" is the HASH of the log's public key, calculated over the DER
     encoding of the key represented as SubjectPublicKeyInfo.'
    ...to...
    '"LogID" is the DER-encoding of an OID, excluding the ASN.1 tag and
     length bytes, that the log operator has allocated for the purpose of
     uniquely identifying this log.'

 3. Add the LogID OID to the log metadata.

 Any better ideas?

-- 
-------------------------------------+-------------------------------------
 Reporter:                           |      Owner:
  [email-masked]           |  [email-masked]
     Type:  enhancement              |     Status:  new
 Priority:  major                    |  Milestone:
Component:  rfc6962-bis              |    Version:
 Severity:  -                        |   Keywords:
-------------------------------------+-------------------------------------

Ticket URL: <http://trac.tools.ietf.org/wg/trans/trac/ticket/105>
trans <http://tools.ietf.org/trans/>

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From: "trans issue tracker" <[email-masked]>
Date: Fri, 21 Aug 2015 14:08:53 -0000

#105: Shrink LogID

Comment (by [email-masked]):

 The ASN.1 tag byte can be omitted in my proposal because we'd know it's an
 OID from the context, and the length byte(s) can be omitted because
 <1..2^8-1> already tracks the variable length for us.

 Severity:  -                        |  Resolution:
 Keywords:                           |

Ticket URL: <http://trac.tools.ietf.org/wg/trans/trac/ticket/105#comment:1>
trans <http://tools.ietf.org/trans/>