diff --git a/.gitignore b/.gitignore
index 36e9cc0..470c161 100644
--- a/.gitignore
+++ b/.gitignore
@@ -13,9 +13,13 @@
 ?*.gitignore.*
 ?*.gitignore.*/
 *.gitomit
-*.gitomit/
 *.gitomit.*
+*.gitomit/
 *.gitomit.*/
+*.nogit
+*.nogit.*
+*.nogit/
+*.nogit.*/
 # 保留
 !.gitignore
 !.gitignore.*
diff --git a/seafile-ignore.txt b/seafile-ignore.txt
index 6795407..f761786 100644
--- a/seafile-ignore.txt
+++ b/seafile-ignore.txt
@@ -17,6 +17,10 @@
 *.sfomit.*
 *.sfomit/
 *.sfomit.*/
+*.nosf
+*.nosf.*
+*.nosf/
+*.nosf.*/
 
 .DS_Store
 */.DS_Store
diff --git a/ticc.js b/ticc.js
index 8df5475..5e45cf2 100644
--- a/ticc.js
+++ b/ticc.js
@@ -1,5 +1,5 @@
-// const BigNumber=require('bignumber.js') // 处理整数 https://github.com/MikeMcl/bignumber.js
-const BigInt = require('big-integer') // 处理整数 https://github.com/peterolson/BigInteger.js
+// const BigNumber=require('bignumber.js') // 处理整数 https://github.com/MikeMcl/bignumber.js // size: 360K
+const BigInt = require('big-integer') // 处理整数 https://github.com/peterolson/BigInteger.js // size: 188K. ethers.js 24M.
 const crypto = require('crypto')
 const nacl = require('tweetnacl')
 const bs58check = require('bs58check')
@@ -193,6 +193,7 @@ class TicCrypto {
    * @param {option} [{ hasher = my.HASHER, salt, input = my.INPUT, output = my.OUTPUT }={}]
    * @return {String}
    * @memberof TicCrypto
+   * 返回结果不包含 0x
    */
   static hash_easy (data, { hasher = my.HASHER, salt, input = my.INPUT, output = my.OUTPUT } = {}) {
     // data can be anything, but converts to string or remains be Buffer/TypedArray/DataView
@@ -264,9 +265,11 @@ class TicCrypto {
     // data 应当是 encrypt 输出的数据类型
     if (mode === 'ecrsa') {
       if (key?.prikey && key?.pubkey) {
-        return ecrsa.decryptMessage(data, key?.prikey, key?.pubkey)
+        return ecrsa.decryptMessage(data, key.prikey, key.pubkey)
+      } else if (key?.receiverPrikey && key?.senderPubkey) {
+        return ecrsa.decryptMessage(data, key.receiverPrikey, key.senderPubkey)
       } else {
-        return ecrsa.decryptMessage(data, key?.receiverPrikey, key?.senderPubkey)
+        return null
       }
     } else if (mode === 'ecc') {
       try {
@@ -533,6 +536,8 @@ class TicCrypto {
       return `m/44'/60'/${path}`
     } else if (coin === 'TIC') {
       return `m/44'/60000'/${path}`
+    } else if (coin === 'MATIC') { // Polygon 测试网 (Mumbai): 80001
+      return `m/44'/137'/${path}`
     } else if (/[A-Z]{3}/.test(coin)) {
       return `m/44'/60${this.alpha_to_digit(coin)}'/${path}`
     } else {
@@ -1097,7 +1102,7 @@ class TicCrypto {
     // hash为64hex字符，sig为128hex字符。返回用hex表达的距离。
     if (this.is_signature({ sig: sig }) && this.is_hash({ hash })) {
       var hashSig = this.hash_easy(sig) // 把签名也转成32字节的哈希，同样长度方便比较
-      return (BigInt('0x' + hash) - BigInt('0x' + hashSig)).toString(16).replace(/^-/, '')
+      return (new BigInt(hash, 16) - new BigInt(hashSig, 16)).toString(16).replace(/^-/, '') // if using bignumber.js: (BigInt('0x' + hash) - BigInt('0x' + hashSig)).toString(16)
     }
     return null
   }
@@ -1455,15 +1460,18 @@ class TicCrypto {
     return '04' + this.padStart(x.toString(16), 64, '0') + this.padStart(y.toString(16), 64, '0')
   }
 
+  // cosh: content hash. 最核心的纯hex的内容地址，没有任何额外标记。同一个内容的cosh是唯一的，而cid是在cosh基础上有各种不同的编码。cid建议叫做 coid.
   static cid_to_cosh ({ cid }) {
     if (/^[Q|1]/.test(cid)) {
-      return this.b58_to_hex(cid).slice(4)
+      return this.b58_to_hex(cid).slice(4) // 前2字节是 cid0 的字节序数标记
     } else if (/^[b|B]/.test(cid)) {
-      return this.b32_to_hex(cid.substr(1)).slice(8)
+      return this.b32_to_hex(cid.substr(1)).slice(8) // 前4字节是 cid1 的标记
     } else if (/^z/.test(cid)) {
       return this.b58_to_hex(cid.substr(1)).slice(8)
     } else if (/^[m|M|u|U]/.test(cid)) {
       return Buffer.from(cid.substr(1), 'base64').toString('hex')
+    } else if (/^9/.test(cid)) {
+      return new BigInt(cid.substr(1)).toString(16).slice(7) // BigInt toString(16) 后，去掉了 01551220... 的打头的 0，所以只有7位需要跳过了
     }
   }
 
@@ -1522,6 +1530,8 @@ class TicCrypto {
         converted = Buffer.from(fullHex, 'hex').toString('base64')
       } else if (cidBase === 'b64') {
         converted = Buffer.from(fullHex, 'hex').toString('base64').replace(/=/g, '')
+      } else if (cidBase === 'b10') {
+        converted = new BigInt(fullHex, 16).toString()
       }
       return multibase[cidBase] + converted
     }