a set of control plane settings and components. While the entire mesh respects the same APIs and config,
apps may target different 'environments' which contain different instances and variants of Istio.

- Better security: separate Istio components reside in different namespaces, allowing different teams or
roles to manage different parts of Istio. For example, a security team would maintain the

arcfour256
arcfour128
arcfour
aes128-cbc
3des-cbc
```

`--sftp=mac-algos=...` specifies a default set of MAC algorithms in preference order.
This is based on RFC 4253, section 6.4, but with hmac-md5 variants removed because they have 
reached the end of their useful life.

Valid values: 

```
******@****.***
******@****.***
hmac-sha2-256
hmac-sha2-512
hmac-sha1