Sorry I was a little inexact, when I said SHA-2 256 I meant specifically the SHA-2 256 bit (SHA-256) hashing algorithm as opposed to SHA-1 which is considered

Sorry I was a little inexact, when I said SHA-2 256 I meant specifically the SHA-2 256 bit (SHA-256) hashing algorithm as opposed to SHA-1 which is considered weak. Not the key length. Though I suspect a 64 character long random string has sufficient entropy.