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update decrypt_packets.md

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Gered 2021-03-24 18:13:22 -04:00
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decrypt_packets.md
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@ -11,9 +11,9 @@ to what my local login_server instance was sending proved invaluable to me.
## Network Protocol ## Network Protocol
After the initial `0x17` packet sent from the server to the client (which contains the client and server encryption After the initial `0x02` or `0x17` packet sent from the server to the client (which contains the client and server
keys), all subsequent communication between the server and client is encrypted. When you have the full set of packets, encryption keys), all subsequent communication between the server and client is encrypted. When you have the full set
beginning with the `0x17` packet, it is pretty trivial to decrypt the entire set of data. of packets, beginning with the `0x02` or `0x17` packet, it is pretty trivial to decrypt the entire set of data.
```text ```text
'Welcome' packet. id=17, flags=0, size=276 'Welcome' packet. id=17, flags=0, size=276
@ -40,7 +40,8 @@ server_key = 0x4f4b816b
client_key = 0x7865a201 client_key = 0x7865a201
``` ```
Note, sometimes the `0x17` packet will contain significantly less text than what is shown above. The above output is Note, sometimes the packet will contain significantly less text than what is shown above. As well, the first bit of
text may be slightly different depending on if it was received from a login or ship server, etc. The above output is
from a Fuzziqer [newserv](https://github.com/fuzziqersoftware/newserv) I was testing with. from a Fuzziqer [newserv](https://github.com/fuzziqersoftware/newserv) I was testing with.
Also of note is that Sylverant's login_server currently seems to always use identical server and client keys (I believe Also of note is that Sylverant's login_server currently seems to always use identical server and client keys (I believe
@ -73,8 +74,12 @@ I do not have this set up and I cannot be bothered to figure out the janky "Tap"
because I am lazy. And because I have a router running [OpenWrt](https://openwrt.org/) which allows me to easily set up because I am lazy. And because I have a router running [OpenWrt](https://openwrt.org/) which allows me to easily set up
packet mirroring with a special iptables kernel module loaded so that I can capture packets directly from my Gamecube. packet mirroring with a special iptables kernel module loaded so that I can capture packets directly from my Gamecube.
I'm not going to go into details here on setting up either method. If you're knowledgeable enough to be considering If you're running the PSO server yourself, then you can just capture packets from that same machine, no special setup
doing packet capture analysis of any sort in the first place, then you should be able to set up either method yourself. required.
I'm not going to go into details here on setting up any of these methods. If you're knowledgeable enough to be
considering doing packet capture analysis of any sort in the first place, then you should be able to set up either
method yourself.
### Dumping PSO Server/Client Communication Data Dumps with Wireshark ### Dumping PSO Server/Client Communication Data Dumps with Wireshark
@ -82,8 +87,7 @@ It is easy to generate packet data dumps containing _just_ the PSO packet data w
After taking a capture of a PSO server/client session, find the TCP packet sent from the server to the client that After taking a capture of a PSO server/client session, find the TCP packet sent from the server to the client that
contains the `0x17` packet. This should be easy enough to find as it will be one of the first TCP packets sent from the contains the `0x17` packet. This should be easy enough to find as it will be one of the first TCP packets sent from the
server to the client and contains the clear-text string `DreamCast Port Map. Copyright SEGA Enterprises. 1999` (for server to the client and contains a clear-text string similar to `DreamCast Port Map. Copyright SEGA Enterprises. 1999`.
non-BB clients anyway, this tool is aimed at GC anyway so that is all I will be covering ...).
Once you've found this packet, right-click it from the top packet list and select "Follow" then "TCP Stream". This will Once you've found this packet, right-click it from the top packet list and select "Follow" then "TCP Stream". This will
bring up a window that shows the raw data, colour-coded to show data originating from the client and server. Use the bring up a window that shows the raw data, colour-coded to show data originating from the client and server. Use the