Wnode (whisper node) is a command-line diagnostic tool. It does not have a nice user interface, because its main purpose is diagnostic, and it's meant to be very light-weight rather than beautiful. Wnode might be used for different purposes, including:
- running a standalone bootstrap node, in order to set up a private whisper network
- connecting to particular node for debugging or other purposes
- engaging in command-line chat with another peer in order to test its functionality
In case an argument is missing, `wnode` will either use the default value or prompt the user at startup. For security reasons, it is not possible to provide passwords in command-line arguments. In `test` mode, a hardcoded password ("test") is used.
`-savedir`: directory where all incoming messages will be saved as files. Only big messages are stored there, except in `fileexchange` mode where all files are stored there.
my public key: 0x040ef7acd60781c336c52056b3782f7eae45be2063e591ac6b78472dc27ba770010bde445ffd2f3623ad656f3859e00d11ef518df4916c4d4e258c60b15f34c682 enode://15454fc65bbf0031155f4eee83fa732f1454c314e9f78ade9cba4d4a098d29edbf5431764ee65b200169025c3f900cacc3348a000dda7a8a0d9643d0b7618712@127.0.0.1:30379
Upon restarting the bootstrap node, its enode will be different, because the ID is randomly generated. For persistence accross restarts, it is possible to specify an ID stored in a file using the 'idfile' argument.
my public key: 0x04be81a00a90f5c21ead8887eaa254b3f7a37e06f8f2d776dcc46954a228bc50c6fb6dfd155f7e44e6fef9b62fdf6dad041759b864d2cbe4089b6f5c16a817ff46 enode://7d13360f5b1ddcf6947f244639113597a863abba0589d2fa5fffb2816ead0acea6211d5778a8be648e45e81ed881f4c1f5c9bbbf0e79065dfb54bcd97de3beab@127.0.0.1:30379
For two nodes to communicate using symmetric encryption, one of them must assume the role of a bootstrap node, and the second one that of the client. The bootstrap node is started with the `standalone` flag, and the client must connect to it. It is easy to do on the same machine or on a dedicated server. But what if two peers are behind distinct NAT? In that case, you need a third bootstrap node on a dedicated server, which both peers can connect to. At the time of writing we have out test node with the following enode:
The user is prompted for the symmetric encryption password. The symmetric key is derived from this password. The topic will be derived from the password as well, unless it's provided by the user on the command line (which is strongly encouraged for any meaningful communication):
The first number (1493061848) is UNIX timestamp. This format is useful for Mail Client/Server tests. The number in brackets is the ID with which the message is signed. Seeing an ID with only zeros means the message is not signed, although encrypted with the right key. Another `wnode` peer will show the same output:
First line of the output contains the key which should be passed to another peer, and vice versa. Once both clients have entered their peer's public key, the chat session is active.
File exchange is activated with the `fileexchange` flags. Examples here use the `-test` flag for simplicity. Assuming that the incoming messages are to be stored in `/home/tester/tmp/msg`, the resulting command line is:
1493124416 {624fdf6983940c7ffa8a4742f76dc78ae9775c47}: message received and saved as 'aa6f339e830c86718ddf4254038dd9fa8da6494e3f3c856af500a5aeaf0df62d' (4 bytes)
Messages are not displayed, but saved instead. Examine the contents of `/home/tester/tmp/msg/aa6f339e830c86718ddf4254038dd9fa8da6494e3f3c856af500a5aeaf0df62d` to confirm that the message is saved there.
Whisper protocol allows you to exchange messages with other peers only if you are online. But what if you go offline? Will important messages be lost forever? The golang implementation of Whisper v6 has a built-in support for Mail Client/Server functionality, which allows to create very secure (and even dark) anonymous email-like system. Wnode is designed to demonstrate the viability of such project.
Mail Server and Client must have direct connection, since they exchange special kind of messages, which are not propagated any further. The reason for that is simple: if you receive the old (expired) message from the Server, and try to send it to other peers, they will recognise the message as expired, and drop connection with you.
