| Nickname | URL | Started | Notes |
|---|---|---|---|
| Gitta | https://gitta.zeitgitter.net/ | 2019-04-01 | public |
| Diversity | https://diversity.zeitgitter.net/ | 2019-04-04 | cross-timestamping only |
Diversity was chosen to use a slow timestamping mechanism, i.e. one which timestamp servers are unlikely to use. This is used to achieve diversity in the cryptographic algorithms used. Timestamping is one of the few applications of cryptography where offering different algorithms in parallel actually increases robustness.
| Nickname | Country | Maintainer |
|---|---|---|
| Gitta | CH | Andres Obrero, Marcel Waldvogel |
| Diversity | CH | Marcel Waldvogel |
"Maintainer" includes everyone with access to the private key, i.e., anyone who could fake a timestamp for this machine.
| Nickname | Algorithm | Key ID | Interval | Offset | Timestamped by |
|---|---|---|---|---|---|
| Gitta | dsa3072 | 8A0B0941E7C49D65 | 1h | 23m37s | Diversity, stamper, originstamp |
| Diversity | rsa4096 | 453E515FCB1593CB | 1h | 46m19s | Gitta, stamper, originstamp |
| stamper | rsa2046 | 70B61F81 (PGP 2) | 1d | 4h25m | Gitta, Diversity |
| originstamp | Bitcoin | Blockchain | 1d | — | — |
How to read this: Gitta commits, obtains a cross-timestamp from Diversity, and publishes its log every hour, 23 minutes and 37 seconds after the hour.
| Nickname | Publication site |
|---|---|
| Gitta | GitLab, GitHub |
| Diversity | GitLab, GitHub |
| stamper | GitLab, GitHub, own site |
| OriginStamp | own site |
The GitLab and GitHub links can easily and efficiently be mirrored by
anyone interested in maintaining a local copy. The blockchain-like but
very efficient properties of git repositories allow resource-efficient
replication and prevents unnoticed modifications of the history of the
repostitory. The digital signatures of the timestamps guarantees an
effective means of verification in case someone attempts to rewrite
history.
The special nickname stamper is used to refer to the PGP Digital
Timestamping Service,
established in 1995 by Matthew Richardson and still operated by him
on Jersey. Since 2019-03-09, the
signature chain created by stamper is being archived on
GitLab
and
GitHub.
Since 2019-04-03, this archive is being timestamped by Gitta and since
2019-05-26 also by Diversity.
I.e., the PGP Digital Timestamper Timestamped Archive is a normal
git timestamp client, which obtains regular timestamps on its daily commits.
After each hourly commit, Gitta and Diversity email their hashes file
(plus the ID of that commit) to stamper. As soon as the timestamped anser
email is received (shortly after the next even multiple of 5 minutes),
this timestamped answer is being added to the repository. Even though it
is published only about an hour later, the included third-party timestamp
ensures that it has not been modified between the issuance and the
publication.
originstamp is the Blockchain-based OriginStamp
timestamping system. All commits by Diversity and Gitta are also included in
the records searchable at originstamp.org and
committed up to a day later to the Bitcoin blockchain, as described by
OriginStamp.
OriginStamp does provide neither a receipt nor proof of posting which could be added to the repository. Also, OriginStamp does not provide for an independent archival of its issued timestamps, so there is no two-way timestamping.