diff --git a/index.js b/index.js
index fd9c42e..1e02765 100644
--- a/index.js
+++ b/index.js
@@ -273,8 +273,7 @@ module.exports = {
         switch(option.coin){
           case 'BTC': key=hdmaster.derive("m/44'/0'/0'/0/0"); break
           case 'ETH': key=hdmaster.derive("m/44'/60'/0'/0/0"); break
-          case 'TIC': key=hdmaster.derive("m/44'/66'/0'/0/0"); break
-          default: key=hdmaster.derive("m/44'/99'/0'/0/0"); break
+          case 'TIC': default: key=hdmaster.derive("m/44'/60000'/0'/0/0"); break
         }
       }else { // 指定了路径 option.path，例如 "m/44'/0'/0'/0/6" 或 "m/0/2147483647'/1"
         key=hdmaster.derive(option.path)
@@ -292,18 +291,19 @@ module.exports = {
   seed2path(seed, {coin='TIC'}={coin:'TIC'}){
     // 路径规范 BIP44: m/Purpose'/Coin'/Account'/Change/Index,
     // 但实际上 Purpose, Coin 都可任意定；' 可有可无；
-    // Account 最大到 parseInt(0x7FFFFFFF, 16), Coin/Index最大到 parseInt(0xFFFFFFFF, 16)
-    // 后面还可继续延伸 /xxx/xxx/xxx/......    let hash=this.hash(seed, {hasher:'md5'})
+    // Account/Change/Index 最大到 parseInt(0x7FFFFFFF, 16)
+    // 后面还可继续延伸 /xxx/xxx/xxx/......    
+    let hash=this.hash(seed, {hasher:'md5'})
     let part0=parseInt(hash.slice(0,6), 16)
     let part1=parseInt(hash.slice(6,12), 16)
     let part2=parseInt(hash.slice(12,18), 16)
     let part3=parseInt(hash.slice(18,24), 16)
-    let part4=parseInt(hash.slice(24,32), 16)
+    let part4=parseInt(hash.slice(24,30), 16)
+    let path=`${part0}'/${part1}/${part2}/${part3}/${part4}/${part5}`
     switch (coin){
-      case 'BTC': return `m/44'/0'/${part0}'/${part1}/${part2}/${part3}/${part4}`
-      case 'ETH': return `m/44'/60'/${part0}'/${part1}/${part2}/${part3}/${part4}`
-      case 'TIC': 
-      default: return `m/44'/66'/${part0}'/${part1}/${part2}/${part3}/${part4}`
+      case 'BTC': return `m/44'/0'/${path}`
+      case 'ETH': return `m/44'/60'/${path}`
+      case 'TIC': default: return `m/44'/60000'/${path}`
     }
   }
   ,
@@ -769,6 +769,31 @@ module.exports = {
     return null
   }
   ,
+  aiid2regcode(aiid) {
+    const alphabet = 'e5fcdg3hqa4b1n0pij2rstuv67mwx89klyz'
+    const base = 16367
+    let num = (aiid+base)*(base - alphabet.length)
+    let code = ''
+    let mod
+    while ( num > 0) {
+        mod = num % alphabet.length;
+        num = (num - mod) / alphabet.length
+        code = code+alphabet[mod] // 倒序存放
+    }
+    return code
+  }
+  ,
+  regcode2aiid(code) {
+    const alphabet = 'e5fcdg3hqa4b1n0pij2rstuv67mwx89klyz'
+    const base = 16367
+    let len = code.length
+    let num = 0
+    for (let i=0; i < len; i++) {
+        num += alphabet.indexOf(code[i]) * Math.pow(alphabet.length, i)
+    }
+    return num/(base - alphabet.length)-base
+  }
+  ,
   // test: https://iancoleman.io/bitcoin-key-compression/
   // compress: https://hacpai.com/article/1550844562914
   compressPubkey(uncompressed){ // 把 04xy 的非压缩公钥 转成 02x 或 03x 的压缩公钥