Support for encrypted connections.

[MajsterTynek]

I made a script, for AdvancedMacros mod, that logs encryption keys used to a file named keylog.log:

KEY E6FEFDA27AF6D290002EC7BC9F62E8F5 FOR [id: 0xad1ae36a, L:/192.168.1.21:53813 - R:mc.hypixel.net/172.65.238.120:25565]
KEY 801A2DED50FE57C0AC37C8D90699A87A FOR [id: 0x648c0406, L:/192.168.1.21:59582 - R:mc.hypixel.net/172.65.210.134:25565]
KEY 8417CC6430DBF49A02114035EE45346B FOR [id: 0x387d190b, L:/192.168.1.21:60442 - R:mc.hypixel.net/172.65.210.134:25565]
KEY 9B650A12788E120F9597347C3BA78E65 FOR [id: 0xc964c4f5, L:/192.168.1.21:61041 - R:mc.hypixel.net/172.65.219.148:25565]
KEY EEAA925581E6792670175C0DAD41F7F0 FOR [id: 0xad58dc6e, L:/192.168.1.21:61111 - R:mc.hypixel.net/172.65.195.223:25565]
KEY 4F16EAFE841999C217B0E3A8EE8F18FC FOR [id: 0x5100fb74, L:/192.168.1.21:61460 - R:mc.hypixel.net/172.65.237.131:25565]

Could it be possible for this dissector to decrypt captured connections if key is provided?

[uis246]

Not yet. AFAIK wireshark support tls decryption. So it possible to implement it.

[MajsterTynek]

Minecraft uses -aes-128-cfb8 cipher stream.
Shared secret generated by client is used both as IV and key.
https://wiki.vg/Protocol_Encryption#Symmetric_Encryption
I have no idea if TLS supports that.

Here's the script I have mentioned earlier, if anyone wishes to work on this:

-- event JoinWorld --
waitTick()

-- SRG mapping 1.12_stable_39 is used here
-- for other versions revise fields yourself

-- here get all the stuff needed
local baseClass = 'com.theincgi.advancedMacros.AdvancedMacros'
local minecraft = luajava.bindClass(baseClass):getMinecraft()
local netManager = minecraft:func_147114_u().field_147302_e

if netManager:func_150731_c() then
    return -- connection is local
end

if not netManager:func_179292_f() then
    return -- connection not encryypted
end

local logger = function(txt)
    assert(type(txt) == "string", "expected string")
    local file = filesystem.open("~/keylog.log", "a")
    file.writeLine(txt)
    file.close()
end

local channel = netManager.field_150746_k
local decrypt = channel:pipeline():get("decrypt")
local cipher = decrypt.field_150509_a.field_150507_a

local hexIV, IV = '', cipher:getIV()
for idx = 1, #IV, 1 do 
    hexIV = hexIV..string.format('%02X',IV:byte(idx)) 
end

logger( "KEY "..hexIV.." FOR "..channel:toString() )
toast( cipher:getAlgorithm(), hexIV )

It may be run manually or by key bind. Way doesn't matter.
Log is stored in .minecraft\mods\advancedMacros\keylog.log.
We might point to it with a enviroment variable,
so it is done similar to SSLKEYLOGFILE as for TLS.