[PATCH 00/10] Adding RFC3161 time-stamps to tags

Hi all,

this patch series adds RFC3161 time-stamping functionality to git tags. This enables users to create and verify cryptographic time stamp signatures to prove that a commit existed at a certain point in time.

The new RFC3161 time-stamping functionality is independent from GPG signatures. However, GPG signatures include time-stamp signatures and therefore make them robust against removal or replacement.

The time stamp signature is stored in the git tag object header under the `timesig` key, which is equivalent to the format for GPG signatures in signed commits. This facilitates a possible implementation of time-stamped commits in the future.

We added two new helper commands, because of their dependencies on libcurl and libcrypto respectively. If one of the libraries is missing, a warning message is given when one of the new functionalities is used.

We tried to add as much documentation as possible. Especially timestamp-util.c, which depends on libcrypto, is a bit tough to read.

Some configuration variables have been added, where `ts.tsaurl` is the most important, which specifies the Time Stamping Autority to use.

For testing the implemented functionality, the Time Stamping Authority SafeCreative can be used, which is free for non-commercial use: https://tsa.safecreative.org. Simply set the config variable ts.tsaurl to this TSA.

Your feedback is welcome. Kind regards, Anton Wuerfel Phillip Raffeck

Anton Wuerfel (10):
Phillip Raffeck (10):
  Add Testcases for time-stamping functionality
  Documentation for time-stamping functionality
  Documentation: Whitespace fix
  Extending internal CURL wrapper for POST upload
  Make PGP macros global
  Add basic RFC3161 functionality
  Add git-http-timestamp helper tool
  Adding time-stamping helper tool
  Add time-stamping functionality to git verify-tag
  Add time-stamping functionality to git tag

 .gitignore                           |   2 +
 Documentation/config.txt             |  20 ++
 Documentation/git-http-timestamp.txt |  32 ++
 Documentation/git-tag.txt            |  32 +-
 Documentation/git-timestamp-util.txt |  52 +++
 Documentation/git-tsa-store.txt      |  68 ++++
 Documentation/git-verify-tag.txt     |  28 +-
 Makefile                             |  15 +
 builtin/tag.c                        |  55 +++-
 builtin/verify-tag.c                 |  61 +++-
 command-list.txt                     |   2 +
 gpg-interface.c                      |   3 -
 gpg-interface.h                      |   3 +
 http-timestamp.c                     |  76 +++++
 http.c                               |  30 +-
 http.h                               |  17 +-
 remote-curl.c                        |   2 +-
 rfc3161.c                            | 219 +++++++++++++
 rfc3161.h                            |  12 +
 t/t7031-verify-tag.sh                |  69 ++++
 timestamp-util.c                     | 615 +++++++++++++++++++++++++++++++++++
 21 files changed, 1380 insertions(+), 33 deletions(-)
 create mode 100644 Documentation/git-http-timestamp.txt
 create mode 100644 Documentation/git-timestamp-util.txt
 create mode 100644 Documentation/git-tsa-store.txt
 create mode 100644 http-timestamp.c
 create mode 100644 rfc3161.c
 create mode 100644 rfc3161.h
 create mode 100755 t/t7031-verify-tag.sh
 create mode 100644 timestamp-util.c