4VtHfikE

1encodedPutPolicy = "eyJzY29wZSI6Im15LWJ1Y2tldDpzdW5mbG93ZXIuanBnIiwiZGVhZGxpbmUiOjE0NTE0OTEyMDAsInJldHVybkJvZHkiOiJ7XCJuYW1lXCI6JChmbmFtZSksXCJzaXplXCI6JChmc2l6ZSksXCJ3XCI6JChpbWFnZUluZm8ud2lkdGgpLFwiaFwiOiQoaW1hZ2VJbmZvLmhlaWdodCksXCJoYXNoXCI6JChldGFnKX0ifQ==";
2SecretKey ="MY_SECRET_KEY";
3	
4signdString = "c10e287f2b1e7f547b20a9ebce2aada26ab20ef2"
5	
6hash[string_String, method_String : "SHA"] := 
7  FromCharacterCode@
8   Interpreter["HexInteger"]@
9    StringPartition[IntegerString[Hash[string, method], 16], 2];
10
11HMAC[key_String, message_String, method_String: "SHA", 
12   blockSize_Integer: 64] := 
13  Module[{char54, char92, key2, ipad, opad}, {char54, char92} = 
14    FromCharacterCode /@ {54, 92};
15   key2 = 
16    Switch[StringLength@key, blockSize, key, l_ /; l > blockSize, 
17     hash[key, method], _, 
18     StringPadRight[key, blockSize, FromCharacterCode@0]];
19   ipad = 
20    FromCharacterCode[
21     BitXor @@ 
22      Map[ToCharacterCode, {StringRepeat[char54, blockSize], key2}]];
23   opad = 
24    FromCharacterCode[
25     BitXor @@ 
26      Map[ToCharacterCode, {StringRepeat[char92, blockSize], key2}]];
27   hash@StringJoin[opad, hash@StringJoin[ipad, message]]];
28	
29HMAC[SecretKey, encodedPutPolicy]