Re: Proof for a creation date

2016-12-30 Thread Richard Ulrich
Hi Bertram, sorry for the late answer.  Blockchain was mentioned in some answers, but nothing in concrete. Check this out: https://github.com/opentimestamps Rgds Richard Am Freitag, den 02.12.2016, 03:12 +0100 schrieb Bertram Scharpf: > Hi, > > we all know that kidnappers do publish a picture o

Re: Proof for a creation date

2016-12-07 Thread NdK
Il 07/12/2016 09:53, Andrew Gallagher ha scritto: > No signature can possibly attest that something is valid *forever*. Well, "till the heat death of the Universe" can be enough for any practical purpose :) > You're right that stapling is absolutely required in a data at rest > use case, because

Re: Proof for a creation date

2016-12-07 Thread Andrew Gallagher
> On 7 Dec 2016, at 05:50, NdK wrote: > > The "stapling" part is the hardest, since with OCSP usually you need to > verify that something is valid "now", while with a GPG signature you > should be able to attest that something will be valid "forever". No signature can possibly attest that somet

Re: Proof for a creation date

2016-12-06 Thread NdK
Il 07/12/2016 00:27, Andrew Gallagher ha scritto: > I don't see any reason why it couldn't be done in principle - anyone who > wants could set up an "authority" that produces a regular, signed list of all > the certificates it currently trusts at each point in time. The trick is a) > making sur

Re: Proof for a creation date

2016-12-06 Thread Andrew Gallagher
I don't see any reason why it couldn't be done in principle - anyone who wants could set up an "authority" that produces a regular, signed list of all the certificates it currently trusts at each point in time. The trick is a) making sure that revocations get submitted to the authority in a time

Re: Proof for a creation date

2016-12-06 Thread NdK
Il 06/12/2016 23:14, Andrew Gallagher ha scritto: >> That could actually reduce trust in any PGP signature, unless there's a >> way to timestamp 'something' that says "as of 'now' this key have not >> been revoked". Ideally that attestation should be included with the >> signature itself > So, es

Re: Proof for a creation date

2016-12-06 Thread Andrew Gallagher
So, essentially OCSP? Andrew Gallagher > On 6 Dec 2016, at 21:42, NdK wrote: > > That could actually reduce trust in any PGP signature, unless there's a > way to timestamp 'something' that says "as of 'now' this key have not > been revoked". Ideally that attestation should be included with the

Re: Proof for a creation date

2016-12-06 Thread NdK
Il 06/12/2016 12:30, Roman Zeyde ha scritto: > You can also use OpenTimestamps service as described here: > https://petertodd.org/2016/opentimestamps-announcement Interesting! To remain on-topic, I'd like to take the "footnote 3": -8<-- An interesting nuance to this is someone who has stolen a PGP

Re: Proof for a creation date

2016-12-06 Thread Roman Zeyde
You can also use OpenTimestamps service as described here: https://petertodd.org/2016/opentimestamps-announcement On Mon, Dec 5, 2016 at 2:11 PM, Bertram Scharpf wrote: > On Thursday, 01. Dec 2016, 19:59:15 -0800, Schlacta, Christ wrote: > > On Dec 1, 2016 7:43 PM, "Bertram Scharpf" > wrote: >

Re: Proof for a creation date

2016-12-05 Thread Glenn Rempe
On 12/5/16 4:11 AM, Bertram Scharpf wrote: > I might resume it to two possibilities to accomplish the task: > > - Post a digest to a site where you cannot withdraw it > ever and where it can be retrieved by everybody. This > could be a Github issue, on Reddit or Twitter or maybe >

Re: Proof for a creation date

2016-12-05 Thread Bertram Scharpf
On Thursday, 01. Dec 2016, 19:59:15 -0800, Schlacta, Christ wrote: > On Dec 1, 2016 7:43 PM, "Bertram Scharpf" wrote: > > > > we all know that kidnappers do publish a picture of their > > hostage holding up a todays newpaper. The purpose of this is > > to proof that the victim was alive _after_ a

Re: Proof for a creation date

2016-12-04 Thread Stephan Beck
MFPA: > > > On Friday 2 December 2016 at 1:46:00 PM, in > , Stephan Beck > wrote:- > > > >> gpg's signature timestamp (on a given file) would NOT >> be a real proof of >> a document being allegedly signed at that specific >> date or (prior to a >> determined date). > > > Maybe use a digita

Re: Proof for a creation date

2016-12-03 Thread MFPA
-BEGIN PGP SIGNED MESSAGE- Hash: SHA512 On Friday 2 December 2016 at 1:46:00 PM, in , Stephan Beck wrote:- > gpg's signature timestamp (on a given file) would NOT > be a real proof of > a document being allegedly signed at that specific > date or (prior to a > determined date). Mayb

Re: Proof for a creation date [GishPuppy]

2016-12-02 Thread Glenn Rempe
Unfortunately, I think the public key from that service is no longer importable in modern GnuPG. https://gnupg.org/faq/whats-new-in-2.1.html#nopgp2 Trying to import the public key on this page results in no public key being imported. Without this the service cannot be used to verify the signatu

Re: Proof for a creation date

2016-12-02 Thread Glenn Rempe
Tierion creates a Merkle tree of incoming hashes and puts the root of the Merkle tree on the Bitcoin blockchain which proves that the hash was placed there prior to the time embedded in the BTC transaction. You want to use their HashAPI. https://tierion.com/features Other similar services are:

Re: Proof for a creation date [GishPuppy]

2016-12-02 Thread gmane . bl4
Bertram Scharpf wrote: > I want to make evidence that I created a document > _before_ a certain point of time. > http://www.itconsult.co.uk/stamper.htm Gishpuppy | To change the delivery settings for this email, click here: http://www.gishpuppy.com/cgi-bin/edit.py?email=gmane@gishpuppy.co

Re: Proof for a creation date

2016-12-02 Thread Brian Minton
On Fri, Dec 02, 2016 at 01:37:00PM +0800, Quan Zhou wrote: > so GnuPG's timestamping isn't an option for this? > Even X509 has a timestamping feature for this kind of use. > No, because you could just set your computer's clock to anything you want, then create the GnuPG /X509 timestamp. I agre

Re: Proof for a creation date

2016-12-02 Thread Stephan Beck
Hi Quan Zhou, Quan Zhou: > so GnuPG's timestamping isn't an option for this? > Even X509 has a timestamping feature for this kind of use. > > On Fri, Dec 2, 2016 at 11:59 AM, Schlacta, Christ > wrote: > >> The easiest way is to publish your code to a publicly controlled source >> with a signatu

Re: Proof for a creation date

2016-12-01 Thread Quan Zhou
so GnuPG's timestamping isn't an option for this? Even X509 has a timestamping feature for this kind of use. On Fri, Dec 2, 2016 at 11:59 AM, Schlacta, Christ wrote: > The easiest way is to publish your code to a publicly controlled source > with a signature on or before your desired date. Not s

Re: Proof for a creation date

2016-12-01 Thread Schlacta, Christ
The easiest way is to publish your code to a publicly controlled source with a signature on or before your desired date. Not sure if there's a *better* way. On Dec 1, 2016 7:43 PM, "Bertram Scharpf" wrote: > Hi, > > we all know that kidnappers do publish a picture of their > hostage holding up a

Re: Proof for a creation date

2016-12-01 Thread Daniel Kahn Gillmor
On Thu 2016-12-01 21:12:50 -0500, Bertram Scharpf wrote: > I want to make evidence that I created a document _before_ a certain > point of time. One approach i've seen recommended is to create a cryptographically-strong digest of the signed document in question and then post it to a public, append