Is it possible to get a SSL SHA2 email certificate for free? How do I make sure it's SHA-2 and not SHA-256, SHA-384, or SHA-512? Apparently the best algorithms are SHA-2 and elliptic-curve-based algorithms. Maybe iOS only supports SHA-256, SHA-384, or SHA-512? If that's the case then it's not really good SSL right? Microsoft officials recommend that customers stop using SHA1 now and begin using certificates based on SHA2, which is much more resistant to collision attacks.