token standard: 0x address and fix token.lua code

lua-examples/ao-standard-token/README.md

@@ -101,6 +101,8 @@ If there is an insufficient balance, then you will receive a `Transfer-Error` Me
 }
 ```
 
+If the Transfer's Recipient is a 0x address, it must be an [EIP55](https://github.com/ethereum/EIPs/blob/master/EIPS/eip-55.md) standard address, since 0x addresses on ao only support the EIP55 address format
+
 ### Mint
 
 The Process itself can `mint` more `Points Coin`!

lua-examples/ao-standard-token/token.lua

@@ -21,6 +21,7 @@
         them the Processes' balance
 ]] --
 local json = require('json')
+local crypto = require(".crypto.init")
 
 --[[
   Initialize State
@@ -72,14 +73,15 @@ end)
   Balances
 ]] --
 handlers.add('balances', handlers.utils.hasMatchingTag('Action', 'Balances'),
-             function(msg) ao.send({ Target = msg.From, Data = json.encode(Balances) }) end)
+             function(msg) ao.send({ Target = msg.From,  Data = json.encode(Balances) }) end)
 
 --[[
   Transfer
 ]] --
 handlers.add('transfer', handlers.utils.hasMatchingTag('Action', 'Transfer'), function(msg)
   assert(type(msg.Tags.Recipient) == 'string', 'Recipient is required!')
   assert(type(msg.Tags.Quantity) == 'string', 'Quantity is required!')
+  assert(verifyEccAddress(msg.Tags.Recipient) == true, 'Ecc recipient must be EIP55')
 
   if not Balances[msg.From] then Balances[msg.From] = 0 end
 
@@ -137,3 +139,45 @@ handlers.add('mint', handlers.utils.hasMatchingTag('Action', 'Mint'), function(m
     })
   end
 end)
+
+function verifyEccAddress(address)
+    if isEthereumAddress(address) then
+    -- EIP-55
+        local mixedAddress = toChecksumAddress(address)
+        return mixedAddress == address
+    end
+        return true
+end
+
+function isEthereumAddress(address)
+    if type(address) == "string" and address:sub(1, 2) == "0x" and #address == 42 then
+        local isValid = true
+        for i = 3, #address do
+            local char = address:sub(i, i)
+            if not string.match(char, "%x") then
+                isValid = false
+                break
+            end
+        end
+        return isValid
+    else
+        return false
+    end
+end
+
+function toChecksumAddress(address)
+    address = string.lower(string.gsub(address, "^0x", ""))
+    local hash = crypto.digest.keccak256(address):asHex()
+    local ret = "0x"
+
+    for i = 1, #address do
+        local hashChar = tonumber(string.sub(hash, i, i), 16)
+        if hashChar >= 8 then
+            ret = ret .. string.upper(string.sub(address, i, i))
+        else
+            ret = ret .. string.sub(address, i, i)
+        end
+    end
+
+    return ret
+end