Add RS512, PS256, and PS512 support

With new release of god_crypto v1.4.7, you can now add support for the following algorithms: RS512, PS256, and PS512.

RS512

await rsa.sign(message, { algorithm: "rsassa-pkcs1-v1_5", hash: "sha512" })
await rsa.verify(signature, message,  { algorithm: "rsassa-pkcs1-v1_5", hash: "sha512" });

PS256

await rsa.sign(message, { algorithm: "rsassa-pss", hash: "sha256" });
await rsa.verify(signature, message, { algorithm: "rsassa-pss", hash: "sha256" });

PS512

await rsa.sign(message, { algorithm: "rsassa-pss", hash: "sha512" });
await rsa.verify(signature, message, { algorithm: "rsassa-pss", hash: "sha512" });

[invisal]

Thank. I have checked the problems and I found the problem in my implementation:

• For RS512, the encryption is right, except that I write the wrong oid (using sha256 oid). I use verify code to test the sign code and my verify code does not include checking oid. I will update more test case for this one.
• For PS256, there is small error in my code as well and add more test cases.

The test method for testing PS256 in your code is also wrong. PS256 and PS512 include random salt. That’s mean that it always produce different signature for same message.

I will patch the fix this week and I will update back to you on this issue.

[timonson]

The tests pass now.

I would love to get a code review before I merge these changes: https://github.com/timonson/djwt/pull/44