Using SecureRandom with SHA-256

Question

I have been using SecureRandom with a seeded SHA1PRNG algorithm to create shared randomness between two processes. I recently learned that SHA1 is being deprecated according to NIST's standards, so we are making an effort to switch to SHA256. The problem I've discovered is that SecureRandom ONLY supports SHA1PRNG, at least according to Oracle's documentation. I was wondering if there's a way to use SecureRandom with SHA256, or probably better, what is a suitable alternative to using SecureRandom?

Answer 1

David, as I understand you are referring to this document: http://csrc.nist.gov/publications/nistpubs/800-131A/sp800-131A.pdf

May be, I am missing something. However, what it says:

From January 1, 2011 through December 31, 2013, the use of SHA-1 is deprecated 
for digital signature generation. The user must accept risk when SHA-1 is used, 
particularly when approaching the December 31, 2013 upper limit.

However, below it says

For all other hash function applications, the use of SHA-1 is acceptable. The 
other applications include HMAC, Key Derivation Functions (KDFs), Random Number 
Generation (RNGs and RBGs), and hash-only applications (e.g., hashing passwords 
and using SHA-1 to compute a checksum, such as the approved integrity technique 
specified in Section 4.6.1 of [FIPS 140-2]). 

So, as I understand SHA1 is ok for random number generation.

Answer 2

I agree to Victor's statement overall. But as a further clarification, section 4 of NIST SP800-131a has a table that separates RNGs NOT using RBGs as mentioned in NIST SP800-90 or ANSI X9.62-2005 will time out in 2015.

Answer 3

Use the following code for Android (Java):

SecureRandom random = null;
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
   random = SecureRandom.getInstanceStrong();
} else {
   random = SecureRandom.getInstance("NativePRNG");
}