z/OS OpenSSH and IBM Ported Tools OpenSSH (for z/OS versions older than V2R2) include a port of the popular OpenSSH tools. These tools provide for secure remote login and program execution (ssh) and file transfer (sftp and scp). The sftp and sftp-server commands implement a file transfer program that is similar to ftp, but use ssh for their underlying secure transport. The sftp specification  accounts only for binary transfers. The IBM z/OS sftp client has been enhanced to support ASCII-EBCDIC conversion. Dataset support is not provided.
The Co:Z Co-Processing Toolkit for z/OS includes Co:Z SFTP - a port of the OpenSSH (v6.4p1) sftp-server subsystem and sftp command (renamed as cozsftp). Extensive enhancements have been made to support z/OS facilities such as z/OSS datasets and spool files. z/OS OpenSSH or IBM Ported Tools OpenSSH, as applicable based on the z/OS version, is required since Co:Z does not provide the base ssh and sshd components.
Co:Z is compatible with most existing sftp products (see the section called “Client Requirements”).
Transfer datasets via the get and put commands
Navigate z/OS catalogs via the cd command.
List dataset information and PDS directories via the ls command.
Records SMF 119 records if user has
Support for IBM FTP compatible user exits. A guide to setting up and using these exits can be found here: http://dovetail.com/docs/sftp/coz_sftp_exits.pdf.
Supports direct access to datasets which can be opened in sequential, record mode by the
fopen()C-library routine. This includes:
MVS sequential datasets (QSAM, BSAM, VSAM)
PDS and PDSE members
SYSOUT datasets, including the MVS internal reader
Supports JES2 and JES3 job submission, status and spool file transfer on z/OS 1.9 or later. Future releases of Co:Z SFTP will also support cancel and purge facilities.
Supports text or binary conversion via flexible line-termination rules:
Cr, Lf/Newline, CrLf, Cr and/or Lf, RDW, none
Supports flexible record padding / overflow rules
Can specify dataset dynamic allocation (BPXWDYN) keywords
Can specify name patterns to automatically associate file transfer options to POSIX files and datasets
V1R12 or later, with a minimum machine architecture of z9 and above
Note Users running machine architectures lower than z9 or a z/OS release lower than V1R12 should use Co:Z release 2.4.5.
z/OS V2R2 includes OpenSSH. Earlier versions of z/OS require IBM Ported Tools OpenSSH v1.2 (or later) to be installed. See the version of our Quick Install Guides matching your z/OS OpenSSH version for additional information.
Co:Z SFTP is compatible with a wide variety of operating systems, including Windows, *IX variants, z/OS...
Products supporting the SSH File Transfer Protocol, such as:
Many commercial implementations.
Note: Not all products support all of the Co:Z SFTP extensions. Refer to Client Compatibility for additional information.
 SFTP specification: http://tools.ietf.org/html/draft-ietf-secsh-filexfer-02