DaoKeDao 0.7.2

DaoKeDao 0.7.2

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由 John Chen、moky 养护。

DaoKeDao 0.7.2

  • 作者：
  • Albert Moky

Dao Ke Dao (道可道) -- 消息模块 (Objective-C)

license Version PRs Welcome Platform

此 文档 介绍了一个用于分布式即时通讯的通用 消息模块。

版权 © 2018-2019 Albert Moky

0. 信封

消息信封

/* example */
{
    sender   : "moki@4WDfe3zZ4T7opFSi3iDAKiuTnUHjxmXekk",
    receiver : "hulk@4YeVEN3aUnvC1DNUufCq1bs9zoBSJTzVEj",
    time     : 1545405083
}

1. 内容

/* example */
{
    type     : 0x01,      // message type
    sn       : 412968873, // serial number (message ID in conversation)
    
    text     : "Hey guy!"
}

消息内容类型

typedef NS_ENUM(UInt8, DKDContentType) {
    DKDContentType_Unknown    = 0x00,
    
    DKDContentType_Text       = 0x01, // 0000 0001
    
    DKDContentType_File       = 0x10, // 0001 0000
    DKDContentType_Image      = 0x12, // 0001 0010
    DKDContentType_Audio      = 0x14, // 0001 0100
    DKDContentType_Video      = 0x16, // 0001 0110
    
    DKDContentType_Page       = 0x20, // 0010 0000
    
    // quote a message before and reply it with text
    DKDContentType_Quote      = 0x37, // 0011 0111
    
    DKDContentType_Money      = 0x40, // 0100 0000
//    DKDContentType_LuckyMoney = 0x41, // 0100 0001
//    DKDContentType_Transfer   = 0x42, // 0100 0010

    DKDContentType_Command    = 0x88, // 1000 1000
    DKDContentType_History    = 0x89, // 1000 1001 (Entity history command)
    
    // top-secret message forward by proxy (Service Provider)
    DKDContentType_Forward    = 0xFF  // 1111 1111
};

2. 消息

当用户想要发送一条消息时，客户端在发送之前需要执行两步操作：

  1. 将即时消息加密为安全消息；
  2. 将安全消息签名以确保其为可靠消息。

相应地，当客户端收到一条消息时，它需要执行两个步骤来提取内容：

  1. 验证可靠消息即是安全消息；
  2. 将安全消息解密以获取即时消息。
    Message Transforming
    ~~~~~~~~~~~~~~~~~~~~

    Instant Message  <-->  Secure Message  <-->  Reliable Message
    +-------------+        +------------+        +--------------+
    |  sender     |        |  sender    |        |  sender      |
    |  receiver   |        |  receiver  |        |  receiver    |
    |  time       |        |  time      |        |  time        |
    |             |        |            |        |              |
    |  content    |        |  data      |        |  data        |
    +-------------+        |  key/keys  |        |  key/keys    |
                           +------------+        |  signature   |
                                                 +--------------+
    Algorithm:
        data      = password.encrypt(content)
        key       = receiver.public_key.encrypt(password)
        signature = sender.private_key.sign(data)

即时消息

/* example */
{
    //-------- head (envelope) --------
    sender   : "moki@4WDfe3zZ4T7opFSi3iDAKiuTnUHjxmXekk",
    receiver : "hulk@4YeVEN3aUnvC1DNUufCq1bs9zoBSJTzVEj",
    time     : 1545405083,
    
    //-------- body (content) ---------
    content  : {
        type : 0x01,      // message type
        sn   : 412968873, // serial number (ID)
        text : "Hey guy!"
    }
}

内容 -> JSON 字符串: {"sn":412968873,"text":"Hey guy!","type":1}

安全消息

/**
 *  Algorithm:
 *      string = json(content);
 *      PW     = random();
 *      data   = encrpyt(string, PW);      // Symmetric
 *      key    = encrypt(PW, receiver.PK); // Asymmetric
 */
{
    //-------- head (envelope) --------
    sender   : "moki@4WDfe3zZ4T7opFSi3iDAKiuTnUHjxmXekk",
    receiver : "hulk@4YeVEN3aUnvC1DNUufCq1bs9zoBSJTzVEj",
    time     : 1545405083,
    
    //-------- body (content) ---------
    data     : "9cjCKG99ULCCxbL2mkc/MgF1saeRqJaCc+S12+HCqmsuF7TWK61EwTQWZSKskUeF",
    key      : "WH/wAcu+HfpaLq+vRblNnYufkyjTm4FgYyzW3wBDeRtXs1TeDmRxKVu7nQI/sdIALGLXrY+O5mlRfhU8f8TuIBilZUlX/eIUpL4uSDYKVLaRG9pOcrCHKevjUpId9x/8KBEiMIL5LB0Vo7sKrvrqosCnIgNfHbXMKvMzwcqZEU8="
}

可靠消息

/**
 *  Algorithm:
 *      signature = sign(data, sender.SK);
 */
{
    //-------- head (envelope) --------
    sender   : "moki@4WDfe3zZ4T7opFSi3iDAKiuTnUHjxmXekk",
    receiver : "hulk@4YeVEN3aUnvC1DNUufCq1bs9zoBSJTzVEj",
    time     : 1545405083,
    
    //-------- body (content) ---------
    data      : "9cjCKG99ULCCxbL2mkc/MgF1saeRqJaCc+S12+HCqmsuF7TWK61EwTQWZSKskUeF",
    key       : "WH/wAcu+HfpaLq+vRblNnYufkyjTm4FgYyzW3wBDeRtXs1TeDmRxKVu7nQI/sdIALGLXrY+O5mlRfhU8f8TuIBilZUlX/eIUpL4uSDYKVLaRG9pOcrCHKevjUpId9x/8KBEiMIL5LB0Vo7sKrvrqosCnIgNfHbXMKvMzwcqZEU8=",
    signature : "Yo+hchWsQlWHtc8iMGS7jpn/i9pOLNq0E3dTNsx80QdBboTLeKoJYAg/lI+kZL+g7oWJYpD4qKemOwzI+9pxdMuZmPycG+0/VM3HVSMcguEOqOH9SElp/fYVnm4aSjAJk2vBpARzMT0aRNp/jTFLawmMDuIlgWhBfXvH7bT7rDI="
}

(所有数据默认使用 BASE64 算法进行编码)