Re: [Cfrg] BLS Signature for X.509

Dan Brown <> Thu, 06 October 2016 15:05 UTC

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From: Dan Brown <>
To: Antonio Sanso <>
Thread-Topic: [Cfrg] BLS Signature for X.509
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Date: Thu, 6 Oct 2016 15:04:30 +0000
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Subject: Re: [Cfrg] BLS Signature for X.509
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The risks (as in potential or theoretical risk) of pairing-groups are (1) newer (usual for any new crypto), (2) recent progress in finite field DLP over certain extension fields, e.g Barbulescu et al. quasi-polynomial time [see also].  Does BLS somehow bypass these risks?  Or is there is a choice of pairing-group that is not deemed risky?

From: Antonio Sanso []
Sent: Thursday, October 06, 2016 8:20 AM
To: Dan Brown
Cc: Paul Grubbs;
Subject: Re: [Cfrg] BLS Signature for X.509

hi Dan

On Oct 5, 2016, at 8:18 PM, Dan Brown <<>> wrote:

Hi Antonio,

Can you briefly expand on the advantages of BLS, especially the aggregation of chains [citing also a reference]?

here a couple of references

AFAIU if the signature used is BLS  there is not need to calculate the certificate chain since any “node” involved can "fully proof" the “chain” .

  How well are these advantages aligned with IETF needs?  At the moment, I’m a little skeptical that the benefits (smaller chains?) outweigh the risks (relying on pairing-groups), but I could be wrong.

are  you aware of any risk of using BLS. I am not so far….

Just to be clear, although BLS uses pairing-groups, it does not have any escrow worries (unlike IBE etc.), or am I badly mistaken?

Is BLS standardized elsewhere (ISO, IEEE 1363*, etc.)?

In any event, you could prepare an individual I-D to propose BLS to IETF, although I do not how much it would be accepted.

if there is any interest I would be happy to take a stub and write a draft. Is there anyone interested to join the effort?



Pairing-groups have been proposed for in use IETF before:

Best regards,


From: Cfrg [] On Behalf Of Paul Grubbs
Sent: Wednesday, October 05, 2016 1:53 PM
To: Antonio Sanso <<>>
Subject: Re: [Cfrg] BLS Signature for X.509

The IETF does play an important role in the process, but most people (at least in the US) won't consider anything in crypto 'standardized' unless it involves NIST.

On Wed, Oct 5, 2016 at 5:09 AM, Antonio Sanso <<>> wrote:
hi Paul,

thanks. Isn’t where this group can help though (namely standardization) ?



On Oct 4, 2016, at 6:01 PM, Paul Grubbs <<>> wrote:

BLS signatures would be nice for many reasons. The lack of standardized pairing groups makes it a little difficult from a deployability perspective, I think.

On Tue, Oct 4, 2016 at 2:12 AM, Antonio Sanso <<>> wrote:
anyome :S ?

On Sep 30, 2016, at 8:57 AM, Antonio Sanso <<>> wrote:

> hi *,
> sorry for the noise.
> I was wondering if it was already discussed the idea to use BSL Signature for X.509.
> AFAIK this will avoid certificate chains thanks to the signature aggregation property…
> If this was already discussed I apologize.
> If not WDYT about this?
> regards
> antonio
> _______________________________________________
> Cfrg mailing list

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