X-Git-Url: https://git.mxchange.org/?p=quix0rs-apt-p2p.git;a=blobdiff_plain;f=TODO;h=0654dba2b87abfd22450402df4f2c7de704e42b9;hp=7a586fe9a2c4b15861764d4b103f9bcd22a2f5f0;hb=194d18a4f4f1c615eecc7d93f379497e0eb586cd;hpb=a9f0deccc4673d5332622ce40407ff009af6c8a3

diff --git a/TODO b/TODO
index 7a586fe..0654dba 100644
--- a/TODO
+++ b/TODO
@@ -1,9 +1,41 @@
-Add all cache files to the database.
-
-All files in the cache should be added to the database, so that they can
-be checked to make sure nothing has happened to them. The database would
-then need a flag to indicate files that are hashed and available, but
-that shouldn't be added to the DHT.
+Use GPG signatures as a hash for files.
+
+A detached GPG signature, such as is found in Release.gpg, can be used
+as a hash for the file. This hash can be used to verify the file when
+it is downloaded, and a shortened version can be added to the DHT to
+look up peers for the file. To get the hash into a binary form from
+the ascii-armored detached file, use the command
+'gpg --no-options --no-default-keyring --output - --dearmor -'. The
+hash should be stored as the reverse of the resulting binary string,
+as the bytes at the beginning are headers that are the same for most
+signatures. That way the shortened hash stored in the DHT will have a
+better chance of being unique and being stored on different peers. To
+verify a file, first the binary hash must be re-reversed, armored, and
+written to a temporary file with the command
+'gpg --no-options --no-default-keyring --output $tempfile --enarmor -'.
+Then the incoming file can be verified with the command
+'gpg --no-options --no-default-keyring --keyring /etc/apt/trusted.gpg
+--verify $tempfile -'.
+
+All communication with the command-line gpg should be done using pipes
+and the python module python-gnupginterface. There needs to be a new
+module for GPG verification and hashing, which will make this easier.
+In particular, it would need to support hashlib-like functionality
+such as new(), update(), and digest(). Note that the verification
+would not involve signing the file again and comparing the signatures,
+as this is not possible. Instead, the verify() function would have to
+behave differently for GPG hashes, and check that the verification
+resulted in a VALIDSIG. CAUTION: the detached signature can have a
+variable length, though it seems to be usually 65 bytes, 64 bytes has
+also been observed.
+
+
+Consider what happens when multiple requests for a file are received.
+
+When another request comes in for a file already being downloaded,
+the new request should wait for the old one to finish. This should
+also be done for multiple requests for peer downloads of files with
+the same hash.
 
 
 Packages.diff files need to be considered.
@@ -30,6 +62,14 @@ and not the headers, and also misses the requests for downloads sent to
 other peers.
 
 
+Rehash changed files instead of removing them.
+
+When the modification time of a file changes but the size does not,
+the file could be rehased to verify it is the same instead of
+automatically removing it. The DB would have to be modified to return
+deferred's for a lot of its functions.
+
+
 Consider storing deltas of packages.
 
 Instead of downloading full package files when a previous version of