ssh-dss
```

`--sftp=kex-algos=...` specifies the supported key-exchange algorithms in preference order.

Valid values: 

```
curve25519-sha256
******@****.***
ecdh-sha2-nistp256
ecdh-sha2-nistp384
ecdh-sha2-nistp521
diffie-hellman-group14-sha256
diffie-hellman-group16-sha512
diffie-hellman-group14-sha1
diffie-hellman-group1-sha1
```