JEP 287: SHA-3 Hash Algorithms

Summary

Implement the SHA-3 cryptographic hash functions (BYTE-only) specified in NIST FIPS 202.

Non-Goals

This JEP will not implement the SHAKE128 and SHAKE256 extendable-output functions (XOFs) because they are not approved as hash functions. The latest PKCS11 v2.40 draft does not contain SHA-3 support. Thus, there is no change to the "SunPKCS11" provider. Also, this JEP will not implement SHA-3 based algorithms for other cryptographic functions such as Signatures, MACs, and Ciphers since there are no standards for them yet. Those will be covered in subsequent enhancements and/or JEPs.

Motivation

SHA-2 was published over 10 years ago, and although no significant attack on SHA-2 has been demonstrated, NIST perceived a need for a dissimilar cryptographic hash function as an alternative to SHA-2. Nine years in the making, SHA-3 is the first cryptographic hash algorithm NIST has developed using a public competition and vetting process. FIPS 202 "SHA-3 Standard: Permutation-Based Hash and Extendable-Output Functions" was finalized as a standard in August 2015. Cryptographic vendors such as BouncyCastle started supporting SHA-3 when FIPS 202 was still a draft. Solaris will also support SHA-3 in the coming Solaris 12.0 release. Since hash functions are used extensively in security applications and SHA-3 implementations are already being added by other vendors, it is important to provide support for SHA-3 in the JDK.

Description

FIPS 202 defines four new hash functions: SHA3-224, SHA3-256, SHA3-384, and SHA3-512. These can be implemented as new algorithms of the java.security.MessageDigest API under the standard names "SHA3-224", "SHA3-256", "SHA3-384", and "SHA3-512". No new APIs are necessary, since there are no parameters required.

Here is the list of providers and the corresponding algorithm enhancements:

• "SUN" provider: SHA3-224, SHA3-256, SHA3-384, and SHA3-512
• "OracleUcrypto" provider: SHA-3 digests supported by Solaris 12.0

Testing

The implementation must pass the relevant known-answer tests provided by NIST where the input size is multiple of 8-bits and existing regression and unit tests.