JEP 273: DRBG-Based SecureRandom Implementations

Summary

Implement the three Deterministic Random Bit Generator (DRBG) mechanisms described in NIST 800-90Ar1.

Non-Goals

Provide API for Source of Entropy Input (SEI), or implement approved SEI on all platforms, where "approved" means approved by NIST or FIPS.

Motivation

The JDK has two kinds of SecureRandom implementations. One is platform-dependent and based on native calls or OS devices such as reading /dev/{u}random on Unix, using the CryptoAPI on Windows, and using various preconfigured PKCS11 libraries. The latest releases of Solaris, Linux and Windows already support DRBG, but older releases and embedded systems might not. The other kind is a pure Java implementation that uses an older SHA1-based RNG implementation, which is not as strong as the algorithms used by approved DRBG mechanisms.

The DRBG mechanisms developed and approved by NIST (as in SP 800-90Ar1) use modern algorithms as strong as SHA-512 and AES-256. Each of these mechanisms can be configured with different security strengths and features to match user requirements. Support for these mechanisms is becoming very important in some environments, especially for the U.S. Government.

Description

According to NIST SP 800-90, a random bit generator (RBG, 800-90C) is constructed with a source of entropy input (800-90B and 800-90C) and a DRBG mechanism (800-90Ar1). The source of entropy input provides fresh randomness (entropy) as a seed to the DRBG mechanism, which is then able to continuously generate "random" bit sequences.

APIs

• New methods for SecureRandom matching 800-90C, which allows configuration of a SecureRandom object and specifying additional input in the course of seeding, reseeding, and random-bit generation.

• New methods in SecureRandomSpi, to implement the new methods above.

• A new SecureRandomParameters interface so that additional input can be provided to the new SecureRandom methods.

These new APIs should be generalized enough for any SecureRandom flavors (not just DRBG) and can be added to SecureRandom and SecureRandomSpi.

• A new DrbgParameters class (and its inner classes) implementing SecureRandomParameters to be used by DRBG.

Implementation

• Implement the three DRBG mechanisms (Hash_DRBG, HMAC_DRBG, CTR_DRBG) in 800-90Ar1 (on all platforms).

By-products

• SHA-512/224 and SHA-512/256 secure hash algorithms as described in FIPS 180-4.

• Related HmacSHA512/224 and HmacSHA512/256 algorithms.

Testing

• The DRBG implementations must pass the CAVP test vectors.

• SHA-512/224 and SHA-512/256 test vectors.

• An informal test vector for HmacSHA512/224 and HmacSHA512/256.