Pseudorandom Number Generator

A transaction that generates a pseudorandom number. When the pseudorandom number generate transaction executes, its transaction record will contain the 384-bit array of pseudorandom bytes. The transaction has an optional range parameter. If the parameter is given and is positive, then the record will contain a 32-bit pseudorandom integer r, where 0 <= r < range instead of containing the 384 pseudorandom bits.

When the nth transaction needs a pseudorandom number, it is given the running hash of all records up to and including the record for transaction n-3. If it needs 384 bits, then it uses the entire hash. If it needs 256 bits, it uses the first 256 bits of the hash. If it needs a random number r that is in the range 0 <= r < range, then it lets x be the first 32 bits of the hash (interpreted as a signed integer).

The choice of using the hash up to transaction n-3 rather than n-1 is to ensure the transactions can be processed quickly. Because the thread calculating the hash will have more time to complete it before it is needed. The use of n-3 rather than n-1000000 is to make it hard to predict the pseudorandom number in advance.\

Reference: HIP-351

Field	Description
Range	The specified range to return the pseudorandom number from.

Methods

Method	Type	Requirement
setRange(<range>)	integer	Optional
getRange(<range>)	integer	Optional

Java

//Create the transaction with range set
TransactionResponse transaction = new PrngTransaction()
        //Set the range
        .setRange(250)                
        .execute(client);

//Get the record
TransactionRecord transactionRecord = transaction.getRecord(client);

//Get the number
int prngNumber = transactionRecord.prngNumber;

System.out.println(prngNumber);

//SDK version 2.17.0

JavaScript

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