For my final year project, I'm developing some Bitcoin/Bitcoin related technologies (BIP32, BIP 38, BIP39, Bas58Check encoding/decoding, etc) in pure Node.js (using only native libraries, such as 'crypto').
After writing the module dealing with BIP32 wallet generation, I wrote a bunch of tests trying to cover 100% of statements/branches/functions/lines, but there's one scenario I can't seem to reproduce, due to it being very unlikely to stumble upon.
Given a random seed, you apply HMAC-SHA512 to get the master extended private key. In it, there is a private key, which can be invalid if equal to 0x0000000000000000000000000000000000000000000000000000000000000000 or greater than 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364140.
Have you guys seen any seed which generates an invalid private key? I looked through the internet for such known value and could not find it.
The same can happen when generating children private keys. Is there any known parent private key + parent chain code + index resulting in an invalid private key?
Thanks a ton!