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 n
th 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
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