SHA integrity validation

Hi,

SFTP answers both questions:
authentification, and confidentiality!
But what's about integrity?
I think that a checking via exchange of checksum SHA/MD5 would benefit SFTP largely?
no?

MD5 checksums are supported only by the latest SFTP version 5. Problem is that probably no server supports the version yet. The most widespread SSH server, OpenSSH, supports only version 3.