## IMPORTANT WARNINGS

1. APIs marked with the `@Beta` annotation at the class or method level
are subject to change. They can be modified in any way, or even
removed, at any time. If your code is a library itself (i.e. it is
used on the CLASSPATH of users outside your own control), you should
not use beta APIs, unless you [repackage] them. **If your

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
hmac-sha1-96