翻墙工具-flint

TCP proxy using Enigma rotor cipher.
中文
Simple experimental TCP proxy using Enigma rotor cipher applied to base24 encoded data, written in D. The only dependency is botan.
Flint provides strong integrity and really weak confidentiality, as Enigma is a WWII cipher. It is recommended to use stunnel for some true confidentiality.

Building

dub build --build=release

The example client side config is flint.config and server side flint.config_server. You can start the server using --config=flint.config_server.

Where are my keys?

cd keytool
dub --build=release

The files pubkey.key and privkey.key will be created under the folder keytool. The server requires privkey.key and the client requires pubkey.key.

Usage

Use --config=<file> to specify a config file. Explanations go below.
type should be client or server.
rotors and rings should be the settings of the first, second and third rotors. reflector is the type of the reflector. Only 3 rotors are supported currently. See enigma.d for available types.
On client side, listen and port specify where to listen for application connections and remote and rport specify the server address. On server side, listen and port specify where to listen for clients and remote and rport specify where to forward applications connections to. timeout is the timeout of client or server connections and does not affect application connections. idletimeout affects only the server and specifies the length of inactivity before disconnecting a client.
keyfile specifies the RSA public or private key file. powleadingzero is the required number of leading zero bytes (0x00) in client's proof of work and powfirstbytemax is the the highest acceptable value of the first non-zero byte in client's proof of work. powsalt is the salt value for proof of work hashes. maxdisconnectdelay is the the maximum delay when disconnecting, during which a random delay between 0 and this value will be chosen and the shutdown of connection will only be done after the random delay.

How does it work?

Flint multiplexes application TCP connections in one TCP connection. When started, the client does a proof of work and then connects to the server. The first message sent over the connection is the 'hello' message from client to server, which is a 32-byte proof of work string followed by some random alphabetical data. The server checks the proof of work and replies with a 'cookie' message, which is a 8-byte cookie concatenated with a 26-byte alphabet, followed by some random alphabetical data. The client then replies with a 'key' message, which is a base24 encoded RSA cipher string containing crypto keys, mixed with the two letters unused in the base24 process and followed by some random alphabetical data again. After the server's successful decryption, the handshake is finished. The three handshake messages have no length field and flint clearly has broken behavior that an intact message is required to be received at one time. Spaces are always ignored in flint protocol, so an arbitrary amount of spaces could be added into the message being sent over the wire, making flint data stream look more like plain text and enables flint to be a replacement of bananaphone.
After handshake, the following message structure is used.

[HMAC][length authentication tag][length][payload]

The message will be encoded using base24 and then encrypted using an Enigma machine. Authenticate then encrypt is a bad idea but I have no idea how to implement encrypt-then-authenticate.

from https://github.com/nametoolong/flint
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dub的安装，参见https://dlang.org/download.html#dmd

在64位linux vps上，安装dmd和dub

wget http://downloads.dlang.org/releases/2.x/2.078.1/dmd.2.078.1.linux.tar.xz
tar Jxvf  dmd.2.078.1.linux.tar.xz
cd dmd2

root@RegalMusty-VM:~/dmd2# ls
README.TXT  html         linux  osx      solaris  windows
freebsd     license.txt  man    samples  src
root@RegalMusty-VM:~/dmd2#  cd linux
root@RegalMusty-VM:~/dmd2/linux# ls
bin32  bin64  lib32  lib64
root@RegalMusty-VM:~/dmd2/linux# cd bin64
root@RegalMusty-VM:~/dmd2/linux/bin64# ls
README.TXT  dman  dmd.conf  dumpobj   obj2asm
ddemangle   dmd   dub       dustmite  rdmd
(dmd和dub是可执行文件）
root@RegalMusty-VM:~/dmd2/linux/bin64#
root@RegalMusty-VM:~/dmd2/linux/bin64# echo 'export PATH=$PATH:~/dmd2/linux/bin64'>> /etc/profile
root@RegalMusty-VM:~/dmd2/linux/bin64# . /etc/profile
root@RegalMusty-VM:~/dmd2/linux/bin64# which dmd
/root/dmd2/linux/bin64/dmd
root@RegalMusty-VM:~/dmd2/linux/bin64# which dub
/root/dmd2/linux/bin64/dub
root@RegalMusty-VM:~/dmd2/linux/bin64#
这样dmd和dub就安装好了。

https://github.com/dlang/dub