The original version of the SSH software used various pieces of free software, such as GNU libgmp, but later versions released by SSH Communications Security evolved into increasingly proprietary software.
Originálna verzia SSH softvéru používala rôzne časti slobodného softvéru ako GNU libgmp, ale neskoršie verzie, ktoré uvoľnila SSH Secure Communications sa postupne stávali proprietárnym softvérom.