A 39-year-old login password of Ken Thompson, the co-creator of the UNIX operating system among, has finally been cracked that belongs to a BSD-based system, one of the original versions of UNIX, which was back then used by various computer science pioneers.

In 2014, developer Leah Neukirchen spotted an interesting "/etc/passwd" file in a publicly available source tree of historian BSD version 3, which includes hashed passwords belonging to more than two dozens Unix luminaries who worked on UNIX development, including Dennis Ritchie, Stephen R. Bourne, Ken Thompson, Eric Schmidt, Stuart Feldman, and Brian W. Kernighan.

Since all passwords in that list are protected using now-depreciated DES-based crypt(3) algorithm and limited to at most 8 characters, Neukirchen decided to brute-force them for fun and successfully cracked passwords (listed below) for almost everyone using password cracking tools like John the Ripper and hashcat.

The ones that she wasn't able to crack belonged to Ken Thompson and five other contributors who helped build the Unix system, including Bill Joy, who later co-founded Sun Microsystems in 1986 and designed the Java programming language.

"Ken's password eluded my cracking endeavor. Even an exhaustive search over all lower-case letters and digits took several days (back in 2014) and yielded no result," she wrote in a blog post published Wednesday.

"I also realized that compared to other password hashing schemes (such as NTLM), crypt(3) turns out to be quite a bit slower to crack (and perhaps was also less optimized)."

All Passwords Have Finally Been Cracked, Except Just One!

Earlier this month, Neukirchen posted all her findings on the Unix Heritage Society mailing list and requested other members to help to crack the remaining passwords.

Just 6 days after that, Australian engineer Nigel Williams responded with the plaintext password of Thompson, the father of Unix, which he claimed to have cracked in over 4 days using "an AMD Radeon Vega64 running hashcat at about 930MH/s."

Thompson's password has been revealed as "p/q2-q4!a" — a notation in chess to describe the move "pawn from Queen's 2 to Queen's 4."

Just a day after Willians revealed Thompson's password, another mailing list member, Arthur Krewat, successfully cracked and provided the passwords for four more remaining uncracked hashes.

Here below we have listed plaintext passwords of all Unix luminaries, including their names, usernames and original hashed versions of their passwords:

Ken Thompson, co-inventor of Unix

• Hashed → ZghOT0eRm4U9s
• Plaintext → p/q2-q4!

Dennis Ritchie, co-inventor of BSD and creator of the C programming language

• Hashed → gfVwhuAMF0Trw
• Plaintext → dmac

Brian W. Kernighan, Canadian computer scientist and Unix contributor

• Hashed → ymVglQZjbWYDE:
• Plaintext → /.,/.,

Stephen R. Bourne, creator of the Bourne shell command line interpreter

• Hashed → c8UdIntIZCUIA
• Plaintext → bourne

Eric Schmidt, an early developer of Unix software and Former Google CEO:

• Hashed → FH83PFo4z55cU
• Plaintext → wendy!!!

Stuart Feldman, author of Unix automation tool make and the first Fortran compiler

• Hashed → IIVxQSvq1V9R2
• Plaintext → axolotl

Here's a list of cracked passwords belonging to other computer science pioneers:

Person	Username	Hashes	Plaintext password
Mark Horton	mark	Pb1AmSpsVPG0Y	uio
Kirk McKusick	mckusick	AAZk9Aj5/Ue0E	foobar
Richard Fateman	fateman	E9i8fWghn1p/I	apr1744
Runs a program, not a login shell	network	9EZLtSYjeEABE	network
UNIX-to-UNIX Copy	uucp	P0CHBwE/mB51k	whatnot
Peter Kessler	peter	Nc3IkFJyW2u7E	...hello
Kurt Shoens	kurt	olqH1vDqH38aw	sacristy
Brian W. Kernighan	jkf	9ULn5cWTc0b9E	sherril.
Peter J. Weinberger	pjw	N33.MCNcTh5Qw	uucpuucp
Ernie Co-vax	root	OVCPatZ8RFmFY	cowperso
John Reiser	jfr	X.ZNnZrciWauE	5%ghj
Steve Johnson	scj	IL2bmGECQJgbk	pdq;dq
Bob Kridle	kridle	4BkcEieEtjWXI	jilland1
Keith Sklower	sklower	8PYh/dUBQT9Ss	theik!!!
Robert Henry	henry	lj1vXnxTAPnDc	sn74193n
Howard Katseff	hpk	9ycwM8mmmcp4Q	graduat;
Özalp Babaoğlu	ozalp	m5syt3.lB5LAE	12ucdort
Bob Fabry	fabry	d9B17PTU2RTlM	561cml..
Tom London	tbl	cBWEbG59spEmM	..pnn521

Until now, all members in the list that Neukirchen found have had their passwords cracked except Bill Joy, whose username is bill and hashed password is ".2xvLVqGHJm8M"