一筆交易最終的權重增長 === 先給出猜測 :::info 一筆交易a的權重增長 , 有很大的機率 , 最終會變成任何新發起的交易 , 都會增加a的權重(交易選擇算法是選tip , 盡可能不選lazy tip的算法) ::: 分兩個例子來觀察以上猜測 # 一般節點 node的網路拓樸 ```graphviz graph graphname{ 1 -- 2; 2 -- 3; 3 -- 4; } ``` node $3$ 的DAG ```graphviz digraph init{ rankdir=RL; a[ label="c" color=blue, fontcolor=blue, fontsize=24, shape=box]; b[label="b" color=blue, fontcolor=blue, fontsize=24, shape=box]; c[label="a" color=blue, fontcolor=blue, fontsize=24, shape=box] e[label="e" color=blue, fontcolor=blue, fontsize=24, shape=box] d[label="d" color=blue, fontcolor=blue, fontsize=24, shape=box] 31[label="31" color=pink, fontcolor=pink, fontsize=24, shape=box] 21[label="21" color=blue, fontcolor=blue, fontsize=24, shape=box] 41[label="41" color=blue, fontcolor=blue, fontsize=24, shape=box] 32[label="32" color=blue, fontcolor=blue, fontsize=24, shape=box] 11[label="11" color=blue, fontcolor=blue, fontsize=24, shape=box] 22[label="22" color=blue, fontcolor=blue, fontsize=24, shape=box] 42[label="42" color=blue, fontcolor=blue, fontsize=24, shape=box] 33[label="33" color=blue, fontcolor=blue, fontsize=24, shape=box] 12[label="12" color=blue, fontcolor=blue, fontsize=24, shape=box] 23[label="23" color=blue, fontcolor=blue, fontsize=24, shape=box] 43[label="43" color=blue, fontcolor=blue, fontsize=24, shape=box] a -> c; b -> c; a -> c; b -> c; e -> a; e -> b; d -> a; d -> b; 31->d; 31->d; 21->e; 21->d; 41->e; 41->d; 32->31; 32->21; 11->e; 11->e; 22->21; 22->31; 42->41; 42->31; 33->42; 33->22; 12->11; 12->21; 23->22; 23->32; 43->32; 43->42; } ``` 說明交易內 $11$ 的意義 $xy$ , $x$ 代表 node $x$ , $y$ 代表第 $y$ 秒發起的交易 所以 $11$ 代表 node $1$ 第 $1$ 秒發起的交易 看粉紅色交易 $\color{pink}{31}$ , 代表是 node $3$ 第 $1$ 秒發起的交易 注意到直接或間接指向 $\color{pink}{31}$ 的交易 直接的有 $32$ , $22$ , $42$ 依照 $lazy \space tip$ 的假設 是 node $3$ 附近 latency 低的node發起的交易 , 比較容易增加 $\color{pink}{31}$ 的權重 然後看直接驗證 $32$ , $22$ , $42$ 的 $23$ , $43$ , $33$ 也會增加 $\color{pink}{31}$ 的權重 看一下 node $2$ 的DAG ```graphviz digraph init{ rankdir=RL; a[ label="c" color=blue, fontcolor=blue, fontsize=24, shape=box]; b[label="b" color=blue, fontcolor=blue, fontsize=24, shape=box]; c[label="a" color=blue, fontcolor=blue, fontsize=24, shape=box] e[label="e" color=blue, fontcolor=blue, fontsize=24, shape=box] d[label="d" color=blue, fontcolor=blue, fontsize=24, shape=box] 21[label="21" color=blue, fontcolor=blue, fontsize=24, shape=box] 11[label="11" color=blue, fontcolor=blue, fontsize=24, shape=box] 31[label="31" color=pink, fontcolor=pink, fontsize=24, shape=box] 22[label="22" color=blue, fontcolor=blue, fontsize=24, shape=box] 12[label="12" color=blue, fontcolor=blue, fontsize=24, shape=box] 32[label="32" color=blue, fontcolor=blue, fontsize=24, shape=box] 41[label="41" color=blue, fontcolor=blue, fontsize=24, shape=box] 23[label="23" color=blue, fontcolor=blue, fontsize=24, shape=box] 13[label="13" color=blue, fontcolor=blue, fontsize=24, shape=box] 42[label="42" color=blue, fontcolor=blue, fontsize=24, shape=box] 33[label="33" color=blue, fontcolor=blue, fontsize=24, shape=box] a -> c; b -> c; a -> c; b -> c; e -> a; e -> b; d -> a; d -> b; 21->e; 21->d; 11->e; 11->e; 31->d; 31->d; 22->21; 22->31; 41->e; 41->d; 12->11; 12->21; 32->21; 32->31; 23->22; 23->32; 42->41; 42->31; 13->12; 13->22; 33->22; 33->42; } ``` $13$ 經過廣播從 node $2$ 傳到 node $3$ 一秒後也會增加 $\color{pink}{31}$ 的權重 node $3$ 收到 $13$ 的DAG如下 ```graphviz digraph init{ rankdir=RL; a[ label="c" color=blue, fontcolor=blue, fontsize=24, shape=box]; b[label="b" color=blue, fontcolor=blue, fontsize=24, shape=box]; c[label="a" color=blue, fontcolor=blue, fontsize=24, shape=box] e[label="e" color=blue, fontcolor=blue, fontsize=24, shape=box] d[label="d" color=blue, fontcolor=blue, fontsize=24, shape=box] 31[label="31" color=pink, fontcolor=pink, fontsize=24, shape=box] 21[label="21" color=blue, fontcolor=blue, fontsize=24, shape=box] 41[label="41" color=blue, fontcolor=blue, fontsize=24, shape=box] 32[label="32" color=blue, fontcolor=blue, fontsize=24, shape=box] 11[label="11" color=blue, fontcolor=blue, fontsize=24, shape=box] 22[label="22" color=blue, fontcolor=blue, fontsize=24, shape=box] 42[label="42" color=blue, fontcolor=blue, fontsize=24, shape=box] 33[label="33" color=blue, fontcolor=blue, fontsize=24, shape=box] 12[label="12" color=blue, fontcolor=blue, fontsize=24, shape=box] 23[label="23" color=blue, fontcolor=blue, fontsize=24, shape=box] 43[label="43" color=blue, fontcolor=blue, fontsize=24, shape=box] 13[label="13" color=blue, fontcolor=blue, fontsize=24, shape=box] a -> c; b -> c; a -> c; b -> c; e -> a; e -> b; d -> a; d -> b; 31->d; 31->d; 21->e; 21->d; 41->e; 41->d; 32->31; 32->21; 11->e; 11->e; 22->21; 22->31; 42->41; 42->31; 33->42; 33->22; 12->11; 12->21; 23->22; 23->32; 43->32; 43->42; 13->12; 13->22; } ``` 可以注意到比較久時間後 , node $1$ 發的交易也可能增加 $\color{pink}{31}$ 的權重 # 邊緣節點(edge node) ```graphviz digraph init{ rankdir=RL; a[ label="c" color=blue, fontcolor=blue, fontsize=24, shape=box]; b[label="b" color=blue, fontcolor=blue, fontsize=24, shape=box]; c[label="a" color=blue, fontcolor=blue, fontsize=24, shape=box] e[label="e" color=blue, fontcolor=blue, fontsize=24, shape=box] d[label="d" color=blue, fontcolor=blue, fontsize=24, shape=box] 41[label="41" color=blue, fontcolor=blue, fontsize=24, shape=box] 31[label="31" color=blue, fontcolor=blue, fontsize=24, shape=box] 42[label="42" color=blue, fontcolor=blue, fontsize=24, shape=box] 21[label="21" color=blue, fontcolor=blue, fontsize=24, shape=box] 32[label="32" color=blue, fontcolor=blue, fontsize=24, shape=box] 43[label="43" color=blue, fontcolor=blue, fontsize=24, shape=box] 33[label="33" color=blue, fontcolor=blue, fontsize=24, shape=box] 22[label="22" color=blue, fontcolor=blue, fontsize=24, shape=box] 11[label="11" color=blue, fontcolor=blue, fontsize=24, shape=box] a -> c; b -> c; a -> c; b -> c; e -> a; e -> b; d -> a; d -> b; 41->e; 41->d; 31->d; 31->d; 42->41; 42->31; 21->e; 21->d; 32->21; 32->31; 43->42; 43->32; 11->e; 11->e; 22->21; 22->31; 33->22; 33->42; } ``` edge node 可以注意到 全部node發的交易會幫助 edge node發的交易增加權重 , 會是比較慢才會出現的 看 $41$ 這筆交易就可以看出 只有 $42$ , $33$ , $43$ 可以增加權重 所以edge node 發的交易 , 安全性是比較低的(權重增加的速率比較慢) # 機率分析 # 總結 猜測: :::info 一筆交易a的權重增長 , 有很大的機率 , 最終會變成任何新發起的交易 , 都會增加a的權重(交易選擇算法是選 $tip$ , 盡可能不選 $lazy \space tip$ 的算法) ::: 從以上模擬出來的DAG來看 , 猜測似乎是對的 而目前還提不出詳細的數學證明 ###### tags: `IOTA`