Oraclize: Difference between random methods

Question

I write a smart contract and want to use oraclize for getting random number. Are there any differences between those methods:

Using WolframAlpha:

oraclize_query("WolframAlpha", "random number between 1 and 2^64");

Using Random.org:

oraclize_query(
     "URL",
     "json(https://api.random.org/json-rpc/1/invoke).result.random.data.0",
     '\n{"jsonrpc":"2.0","method":"generateIntegers","params":{"apiKey":"9844ab4d-52ef-4587-9cf3-20a6930a7f6e","n":1,"min":1,"max":1000,"replacement":true,"base":10},"id":1}');

Using oraclize random method:

bytes32 queryId = oraclize_newRandomDSQuery(delay, N, callbackGas); 

In term of price, I see that:

• WolframAlpha: 0.03$/query. unlimited queries.
• Random.org: 0.01$/query. only 1000 requests/day (limited by random.org)
• oraclize_newRandomDSQuery: 0.05$/query.

Please tell me differences in functionality. Thanks

Answer 1

The random data source query is designed so that assuming the ledger hardware enclave isn't compromised, your contract can verify that Oraclize really gave you a random number.

Using Wolfram Alpha or random.org require you to trust those organisations, plus Oraclize and their CDNs, any of whom could cheat undetectably.