update documentation for verification in tlmgr

git-svn-id: svn://tug.org/texlive/trunk@40467 c570f23f-e606-0410-a88d-b1316a301751

1 files changed, 33 insertions, 4 deletions

diff --git a/Master/texmf-dist/scripts/texlive/tlmgr.pl b/Master/texmf-dist/scripts/texlive/tlmgr.pl
index 05e626ec8e3..9f64aa03cb7 100755
--- a/Master/texmf-dist/scripts/texlive/tlmgr.pl
+++ b/Master/texmf-dist/scripts/texlive/tlmgr.pl
@@ -6449,6 +6449,15 @@ Activates user mode for this run of C<tlmgr>; see L<USER MODE> below.
 
 Uses I<dir> for the tree in user mode; see L<USER MODE> below.
 
+=item B<--verify-downloads>
+
+=item B<--no-verify-downloads>
+
+Enables or disables cryptographic verification of downloaded database files.
+A working GnuPG (C<gpg>) binary needs to be present in the path, otherwise
+this option has no effect. See L<CRYPTOGRAPHIC VERIFICATION> below for details.
+
+
 =back
 
 The standard options for TeX Live programs are also accepted:
@@ -7509,6 +7518,25 @@ fallback information, but if you don't like them accumulating (e.g.,
 on each run C<mirror.ctan.org> might resolve to a new host, resulting in
 a different hash), it's harmless to delete them.
 
+=head1 CRYPTOGRAPHIC VERIFICATION
+
+If a working GnuPG binary (C<gpg>) is found, by default verification of
+downloaded files is performed. This can be supressed by specifying
+C<--no-verify-downloads> on the command line, or adding an entry
+C<verify-downloads = 0> to a tlmgr config file.
+
+Verification is performed as follows: For each C<texlive.tlpdb> loaded
+for a repository, the respective checksum C<texlive.tlpdb.sha512> is
+always downloaded, too, and C<tlmgr> confirms whether the checksum
+of the download tlpdb file agrees with the download data. This is done
+in any case.
+
+If cryptographic verification is done, then a signature of the checksum
+file is downloaded and the signature verified. The signature is done with
+the TeX Live Distribution GPG key 0x06BAB6BC, which in turn is signed
+by Karl Berry's key 0x9DEB46C0 and Norbert Preining's key 0x6CACA448.
+All of these keys are obtainable from the standard key servers.
+
 =head1 USER MODE
 
 C<tlmgr> provides a restricted way, called ``user mode'', to manage
@@ -7610,12 +7638,13 @@ ignored.  All other lines must look like
 
 where the allowed keys are C<gui-expertmode> (value 0 or 1),
 C<persistent-downloads> (value 0 or 1), C<auto-remove> (value 0 or 1),
+C<verify-downloads> (value 0 or 1),
 and C<gui-lang> (value as with the command-line option).
 
-C<persistent-downloads>, C<gui-lang>, and C<auto-remove> correspond to
-the respective command line options of the same name.  C<gui-expertmode>
-switches between the full GUI and a simplified GUI with only the
-important and mostly used settings.
+C<persistent-downloads>, C<gui-lang>, C<auto-remove>, and C<verify-downloads>
+correspond to the respective command line options of the same name.  
+C<gui-expertmode> switches between the full GUI and a simplified GUI
+with only the important and mostly used settings.
 
 In addition, the system-wide config file can contain the key
 C<allowed-actions>. The value is a comma-separated list of actions that