Also, a 3GS at least has HW acceleration for AES, SHA-1, and some sort of RSA bignum acceleration. Not sure what the new HW has but I suspect backwards compatib

Also, a 3GS at least has HW acceleration for AES, SHA-1, and some sort of RSA bignum acceleration. Not sure what the new HW has but I suspect backwards compatibility may be a reason for holding SHA-1++ back on iOS.