rsc/tlogdb

Tlogdb is a trivial transparent log client and server. It is meant as more a
starting point to be customized than a tool to be used directly.

A transparent log is a tamper-proof, append-only, immutable log of data
records. That is, if the server were to violate the “append-only, immutable”
properties, that tampering would be detected by the client. For more about
transparent logs, see https://research.swtch.com/tlog.


Server Operations

To create a new log (new server state):

    tlogdb [-f file] newlog $servername

The newlog command creates a new database in file (default tlog.db)
containing an empty log and a newly generated public/private key pair for
the server using the given name.

The newlog command prints the newly generated public key. To see it again:

    tlogdb [-f file] publickey

To add a record named name to the log:

    cat data | tlogdb [-f file] add name

To serve the authenticated log data:

    tlogdb [-a addr] [-f file] serve

The default server address is localhost:6655.


Client Operations

The client maintains a cache database both for performance (avoiding
duplicate downloads) and for storing the server's public key and the most
recently seen log head.

To create a new client cache:

    tlogdb [-c file] newcache key

The newcache command creates a new database in file (default tlogclient.db)
and stores the given public key for later use. The key should be the output
of the tlogdb's server commands newlog or publickey, described above.

To look up a record in the log:

    tlogdb [-a addr] [-c file] lookup name

The default server address is again localhost:6655.


Example

Putting the various commands together in a Unix shell:

    rm -f tlog.db tlogclient.db
    go build

    ./tlogdb newlog myname
    ./tlogdb publickey
    echo hello world | ./tlogdb add greeting
    ./tlogdb serve &

    ./tlogdb newcache $(./tlogdb publickey)
    ./tlogdb lookup greeting

    kill $!