Re: Encrypting a user home folder on a laptop

Thread: Re: Encrypting a user home folder on a laptop

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Re: Encrypting a user home folder on a laptop
United States	2008-02-16 00:46:30
HERE ARE SOME OTHER QUICK READS THAT APPEAR TO BE ACCURATE: SERPENT CIPHER:   HTTP://EN.WIKIPEDIA.ORG/WIKI/SERPENT_%28CIPHER%29 >FROM SERPENT'S SITE - A CLAIM IT IS STRONGER THAN AES:  HTTP://WWW.CL.CAM.AC.UK/~RJA14/SERPENT.HTML AES:  HTTP://EN.WIKIPEDIA.ORG/WIKI/ADVANCED_ENCRYPTION_STANDARD TWO FISH:  HTTP://EN.WIKIPEDIA.ORG/WIKI/TWOFISH BRUCE SCHNEIER ON TWO FISH BEING FAR FROM BROKEN:  HTTP://WWW.SCHNEIER.COM/BLOG/ARCHIVES/2005/11/TWOFISH_CRYPTAN.HTML CIPHER MODES:  HTTP://EN.WIKIPEDIA.ORG/WIKI/BLOCK_CIPHER_MODES_OF_OPERATION ELECTRONIC CODE BOOK (ECB):  HTTP://EN.WIKIPEDIA.ORG/WIKI/ELECTRONIC_CODE_BOOK CHAIN BLOCK CIPHER (CBC):  HTTP://EN.WIKIPEDIA.ORG/WIKI/BLOCK_CIPHER_MODES_OF_OPERATION TRUE CRYPT:  HTTP://EN.WIKIPEDIA.ORG/WIKI/TRUE_CRYPT TRUE CRYPT'S SITE:  HTTP://WWW.TRUECRYPT.ORG/ BRIAN MICEK ON FRIDAY FEBRUARY 15 2008 10:06 PM, SAMUEL HALICKE WROTE: > READ INTRODUCTION TO ALGORITHMS AND GET THE MIT OPEN COURSEWARE FOR > THE BOOK FROM THEIR SITE OR ITUNES UNIV. > > AT LEAST YOU GET A START THAT WAY > > SAM > > ON FEB 15, 2008, AT 6:08 PM, RANDY BARLOW WROTE: > > BMICEKSPEAKEASY.NET WROTE: > >> I SPENT TIME ABOUT A YEAR AGO LOOKING INTO GOOD ENCRYPTION.  AT THAT >; >> TIME, CRYPTSETUP WAS THE BEST BET.  ITS REALLY EASY TO USE.  WITH >; >> CRYPTSETUP, YOUR BEST OFF ENCRYPTING AN ENTIRE FILESYSTEM/PARTITION > >> SO > >> THERE ARE NO RESTRICTIONS REGARDING SIZE. > >> > >> AS FAR AS CIPHERS, THERE ARE THREE POPULAR ONES THAT ARE 256 BITS >; >> IN THE > >> LINUX KERNEL.  YOU'LL HAVE TO PICK THE ONE(S) YOU LIKE BEST. > >> GENERALLY, > >> EVERYONE AGREES SERPENT IS THE STRONGEST, FOLLOWED BY AES THEN >; >> FOLLOWED > >> BY TWOFISH.  FROM MY TESTS, PERFORMANCE OF THE ALGORITHMS IS IN > >> REVERSE > >> ORDER (MEANING TWOFISH IS THE FASTEST).  LINUX IS A BIT BEHIND LAST I > >> CHECKED REGARDING ENCRIPTION MODES OF OPERATION AND SEEMS TO ONLY >; >> OFFER > >> ECB OR CBC.  CBC IS CHAIN BLOCK CIPHER AND IS BASED ON AN IV WHICH IS > >> LIKE AN INDEX INTO YOUR MEDIA.  THE IV IS USED TO ENCRIPT A BLOCK OF > >> DATA SO A PREVIOUS IDENTICAL BLOCK WONT BE IDENTICALLY ENCRYPTED.  AS > >> FAR AS YOUR QUESTION REGARDING ONE-BIT CHANGES, A ONE BIT CHANGE WILL >; >> HAVE THE EFFECT YOU MENTIONED BUT ONLY FOR ONE ENCRYPTED BLOCK. > >> > >> I'D RECOMMEND READING UP ON THE CIPHERS TO SEE WHAT YOU LIKE. > >> THERE HAS > >> BEEN SOME TALK ABOUT TWOFISH BEING BROKEN HOWEVER I FIND IT HARD TO > >> BELIEVE.  THERE HAS BEEN A LOT OF TALK ABOUT TRUECRYPT ON LINUX. > >> FROM >; >> WHAT I CAN TELL, IT SEEMS A BIT MORE ADVANCED AND SUPPORTS DIFFERENT > >> (MORE MODERN?) MODES OF ENCRYPTION. > > >; > THANKS FOR THE REPLY BRIAN!  IN A COURSE I AM TAKING THIS SEMESTER, WE > > HAVE LEARNED THE NITTY GRITTY OF AES, AND I THINK I AM PRETTY HAPPY > > WITH >; > THAT ONE GIVEN A LONG ENOUGH KEY (256 IS WAY PLENTY!)  I HAVE BEEN >; > PLAYING AROUND WITH THE CREATION OF THE FILE FOR THE LOOPBACK BLOCK > > DEVICE FOR DM-CRYPT, AND I HAVE LEARNED SOME SURPRISING THINGS ABOUT > > FILESYSTEMS.  CAN ANYBODY EXPLAIN THE FOLLOWING TO ME? > > >; > IF I CREATE A FILE LIKE THIS: > > >; > DD IF=/DEV/ZERO BS=1000000000 OF=/PATH/TO/CRYTPED/FILE > > >; > IT MAKES A FILE THAT TAKES UP 1 GB OF HARD DRIVE SPACE.  IT TAKES A > > WHILE TO WRITE TO DISK, AND YOU WILL NOTICE THAT THE FILE IS 1 GB WITH >; > LS -L AND YOU WILL ALSO NOTICE A CHANGE IN THE SPACE FOR THE PARTITION > > USING DF. > > >; > IF I CREATE A FILE LIKE THIS: > > >; > DD BS=1 SEEK=1GB IF=/DEV/NULL OF=/PATH/TO/CRYPTED/FILE > > >; > IT MAKES A FILE THAT REPORTS ITSELF TO BE 1 GB LONG BY LS -L, BUT > > DOESN'T SEEM TO WRITE 1 GB TO THE DISK.  ALSO, DF DOESN'T REPORT 1 GB > > LESS THAN BEFORE YOU RUN THE COMMAND. > > >; > WHAT'S HAPPENING HERE?  I HAD ASSUMED BEFORE I DID THIS THAT THE > > OUTPUT > > OF LS -L IS THE ACTUAL NUMBER OF BITS CONSUMED BY A FILE, BUT THAT >; > DOESN'T SEEM TO BE THE CASE ANYMORE. > > >; > I CREATED A FILE USING THE SECOND COMMAND, AND NOW AS I COPY FILES > > INTO >; > IT I CAN SEE THE DISK SPACE GOING DOWN BIT BY BIT.  THIS IS REALLY > > WHAT >; > I WANTED IN THE FIRST PLACE, BUT I AM JUST CONFUSED AS TO WHAT IS > > REALLY > > GOING ON.  COULD ANYBODY EXPLAIN, PLEASE? > > >; > -- > > RANDY BARLOW > > HTTP://ELECTRONSWEATSHOP.COM > > -- > > GENTOO-SECURITYLISTS.GENTOO.ORG MAILING LIST -- GENTOO-SECURITYLISTS.GENTOO.ORG MAILING LIST