Editing Salt (cryptography) (section)

===1970s–1980s===
Earlier versions of [[Unix]] used a [[Passwd (file)|password file]] <code>/etc/passwd</code> to store the hashes of salted passwords (passwords prefixed with two-character random salts). In these older versions of Unix, the salt was also stored in the passwd file (as cleartext) together with the hash of the salted password. The password file was publicly readable for all users of the system. This was necessary so that user-privileged software tools could find user names and other information. The security of passwords is therefore protected only by the one-way functions (enciphering or hashing) used for the purpose. Early Unix implementations limited passwords to eight characters and used a 12-bit salt, which allowed for 4,096 possible salt values.<ref>{{Cite web
 | url = http://cm.bell-labs.com/cm/cs/who/dmr/passwd.ps
 | title = Password Security: A Case History |website=[[Bell Laboratories]]
 | first1 = Robert | last1 = Morris | first2 = Ken | last2 = Thompson | date = 1978-04-03
 | archive-url = https://web.archive.org/web/20130821093338/http://cm.bell-labs.com/cm/cs/who/dmr/passwd.ps
 | archive-date = 2013-08-21
}}</ref>  This was an appropriate balance for 1970s computational and storage costs.<ref>{{cite book |chapter-url=https://www.safaribooksonline.com/library/view/practical-unix-and/0596003234/ch04s03.html |chapter=How Unix Implements Passwords |title=Practical UNIX and Internet Security |edition=3rd |author=Simson Garfinkel |author2=Gene Spafford |author3=Alan Schwartz |publisher=O'Reilly Media |date=2003 |isbn=9780596003234}}</ref>