Overview

The NIST Interoperable Randomness Beacons project, hosted by the Computer Security Resource Center (CSRC), defines and operates a public randomness beacon that broadcasts high-quality, full-entropy random bit-strings at fixed intervals. Each broadcast, called a pulse, is sequence-numbered, timestamped, digitally signed, and cryptographically chained to the previous pulse so that no party, including the beacon operator, can retroactively alter a published value without detection. The project’s goal is interoperability: a common pulse format and REST API so that independent beacon operators can run compatible services. Beacon Format 2.0 is the current prototype (beta), with Format 1.0 retained for reference, and the design is documented in the NIST Internal Report NISTIR 8213.

Key points

• Pulses are emitted every 60 seconds, each carrying a 512-bit full-entropy output value produced by combining multiple hardware entropy sources.
• Every pulse is digitally signed and includes the hash of the previous pulse, forming a hash chain that makes the sequence tamper-evident.
• Pulse fields include a sequence-numbered timestamp, the output value, precommitment and local random values, chaining data, a status code, and a signature over the record.
• A REST API lets clients fetch pulses by Unix time (milliseconds since the epoch), the previous or next pulse relative to a time, the latest pulse, a specific chain and pulse index, and per-pulse certificates; an XSD schema formalizes the data structure.
• The documentation warns explicitly that beacon values are public and must never be used as secret cryptographic keys; they are intended as publicly verifiable, unbiased randomness.
• Interoperability across beacon operators is the central aim, supporting applications that need auditable, third-party randomness for public scrutiny.

Relevance to Truestamp

Truestamp captures external public randomness beacons (including the NIST Randomness Beacon) as entropy sources whose signed, hash-chained pulses provide an independent, tamper-evident time reference. Because a pulse cannot have existed before its published timestamp, incorporating a beacon value into a block strengthens the public randomness guarantees behind Truestamp’s submission-window claims.

Citations

1. Interoperable Randomness Beacons (NIST CSRC). NIST Computer Security Resource Center; Beacon Format 2.0 prototype, documented in NISTIR 8213.