Implementation includes some of functionality provided by OpenSSH.
OpenSSH itself is derivative of the original and free ssh 1.2.12
release by Tatu Ylonen. Aaron Campbell, Bob Beck, Markus Friedl,
Niels Provos, Theo de Raadt, and Dug Song removed many bugs,
re-added newer features and created OpenSSH.
Roumen Petrov adds X.509 certificate support, modernize use of
cryptography library including FIPS mode and creates PKIX-SSH.

Project depend of OpenSSL an excellent cryptography library.
Precise autoconf based testings of available functionality
allows PKIX-SSH to work fine not only with current stable releases
but with upcoming versions or other compatible libraries.
Ancient versions are still supported.

Functional testing ensures portability to many platforms. The list
includes but is not limited to Linux, Android, Solaris, BSD variants
Cygwin, Darwin and AIX.

Enhanced key management allows use of key material stored not only on
file system, but provided from external sources like PKCS#11 module,
loadable cryptography module (engine) or OpenSSL store interface.
Each key material could be used in all supported algorithms.
For instance each server host-key is announced in all supported and
allowed algorithms.
For a key used as client identity adaptive algorithm selection allows
client to chose automatically most suitable algorithm for connection