EntropyPool and Entropy Filter Bit Generator

Use this page to request bits from the entropy pool.

You can request bits as an HTML page in hex, or as binary bytes.

The latter is particularly valuable to request bytes for another EntropyPool, for example.

Request Random Bytes

Entropy bits now in the pool: 15609

Feature Value Notes
Number of bytes required: Current maximum request is 8 bytes. More may be allowed for binary format requests with the limit-by-available-entropy option.
Format you'd like the data in: hexadecimal
hexadecimal without spaces or breaks
binary bytes
Binary is the recommended format for input to another program or EntropyPool so if you set entropy-per-bit of (say) 0.99 and set the limit-by-available-entropy option below, then by counting the input bytes the receiving system can work out exactly how much entropy it has received.

For generating the ASCII representation of a shared private key, eg for a VPN for IKE/ISAKMP authorisation, the "hexadecimal without spaces" format is recommended. For 128 bits of entropy for a 128-bit key request 16 bytes, for 256 bits of entropy for a 256-bit key request 32 bytes, etc. WARNING: if you are going to use this for anything critical or sensitive (entirely at your own risk) then:

  • Run a copy of this site locally where traffic cannot be overseen.
  • Add some key material (add/insert characters) from another source, eg generated by you such as something like a new password, in case there is a flaw in this generator.
Limit output bytes to the available entropy in the pool: limit output
If true then you only get data representing real entropy in the pool and thus possibly less than you requested, else if the pool runs empty you will get extra bits synthesised by the secure PRNG (pseudo-random number generator).
Press the button to get your newly-minted bytes!

Request UK National Lottery numbers (6 different numbers in range 1--49) for fun only:

Dot-com name generator for fun only:

Request a unique Java serialVersionUID for a Serializable object:

Request this page again but don't fetch any random bits:

This site does not record what bytes it has sent to whom, but:

  1. You should not trust this pronouncement.
  2. You do not know who might have observed the data in transit to you.
  3. Unless you used the `limit-by-available-entropy' flag the data returned may not represent real noise.
  4. No warranties are made that the numbers are good for any purpose whatsoever, nor that the generator and its environment are uncompromised.
So you should almost certainly regard any data you receive from this site as insecure, and not a good source of entropy for generating (for example) cryptographically-secure keys for sensitive data.

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