Hardening RSA keys for PKI and SSH

[ghost]

Hello,

For security reasons, I've :

• added RSA 16384 for PKI
• added RSA 4096 for SSH
• switched the default SSH to 2048 because it's the default value when we use ssh-keygen

Regards

[jefferai]

I'll merge this if you remove the 16384 bit value for RSA. I'm wary of people that don't really know what they're doing selecting this because it exists and such computations could bring a Vault server to its knees (remember, it's a shared process). I know of no evidence that such high bit values are necessary (usually if you need better security the answer is "don't use RSA any more"); even 8192 bits are not often seen in the wild, in favor of other key types (such as much smaller and faster elliptic curve types).