Entry 30585 (Berkeley CSUA MOTD)

Berkeley CSUA MOTD:Entry 30585

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2025/07/12 [General] UID:1000 Activity:popular

7/12

2004/6/3-4 [Computer/SW/Security] UID:30585 Activity:high

6/3     What kind of encryption scheme is used in the German Enigma Machine?
        Is it symmetrical encryption? Why was it so hard to crack in the 40s?
        \_ I believe it was a poly-alphabetic cypher that changed on each
           letter (therefore, yes it was symmetric).  So, the first
           letter in a mesage would use one cypher, the next would use
           another. The standard machine used 3 wheels, so the opertator
           would set the 3 wheels to that day's setting, and type in
           either the message or the cypher-text.  Each would produce the
           other.  This kind of message is easy to break with a computer,
           and lots of example messages, but I wouldn't want to work it
           out on a sheet of paper.  Of course the setting changed
           (daily?) frequently, and when the settings changed, you got
           almost a whole new encryption problem.  There are LOTS of pages
           on this, and example java applets.  Google.
           \_ And if you like novelisations, Neal Stephenson's _Cryptonomicon_
              and Robert Harris' _Enigma_ cover both the math and the history
              quite nicely.
           \_ Actually, the German field soldiers tended to set them (there
              were more wheels later on) to swear words, so there was
              actually a decent message depth. -chialea
           \_ They had plenty of sample messages when nearly every unit that
              had one all sent happy birthday messages to hitler.
           \_ interesting weakness- the rotors were hard-wired- so for a given
              position the mapping of one letter was reversible.  Say the code
              key was XXX and you typed A and got a Z... if you had typed a Z
              you would also get a A.  For the rotors in that position.  Ask
             chialea for how useful that actually would be.     -brain
        \_ Applet http://www.ugrad.cs.jhu.edu/~russell/classes/enigma

2025/07/12 [General] UID:1000 Activity:popular

7/12

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2010/3/9-30 [Computer/HW/CPU, Computer/SW] UID:53748 Activity:nil

3/9     http://www.engadget.com/2010/03/09/1024-bit-rsa-encryption-cracked-by-carefully-starving-cpu-of-ele
        I failed to see why you must starve the CPU of electricity. Why
        can't you just simulate that in software?
        \_ And if you can simulate that in software, why not just single-
           stepping the simulated CPU and get the key out?
	...

2009/12/29-2010/1/19 [Computer/SW/Security] UID:53607 Activity:nil

12/29   Sounds like the GSM encryption key has been recovered via a
        brute force attack:
        http://www.nytimes.com/2009/12/29/technology/29hack.html
	...

2008/8/5-10 [Computer/HW/Laptop] UID:50783 Activity:nil

8/5     Laptop with names of 33K people in the 'Clear' program stolen.  Data
        was (of course) unencrypted.
        http://www.schneier.com/blog/archives/2008/08/laptop_with_tru.html
        \_ http://news.yahoo.com/s/nm/20080805/bs_nm/tjx_theft_charges_dc
           When are people going to learn to encrypt sensitive data?
           \_ When encryption becomes transparent enough that noone has
	...

2008/8/5-10 [Computer/HW/Laptop] UID:50787 Activity:nil

8/5     how is power usage on my laptop if i encrypt everything
        http://www.schneier.com/blog/archives/2008/08/laptop_with_tru.html
        \_ Steve Gibson's analysis on performance was that Trucrypt on a WinXP
           laptop was actually faster, but I don't know about battery.
           laptop was actually faster, but I don't know about battery life.
           \_faster?  How can that be?  Also, I don't see that in the article.
	...

2008/6/25-7/14 [Computer/SW/Security] UID:50380 Activity:nil

6/25    some XCF or CSUA person had a web page about a project they were
        working on where I set up a machine, and you set up a machine
        somewhere, and they both passively back each other, i believe with
        an encryption key so i can't read your backups.  when your disk
        catches on fire, i just give you a copy of your data.  anyone remember
        the name of this?
	...

2008/6/9-12 [Computer/SW/Languages/C_Cplusplus, Computer/SW/Security] UID:50194 Activity:nil

6/8     CSUA code guru please help. I need to see my random number
        generator with a good seed (I just need random 18 bit
        identifiers). The usual time(NULL) is OK, except my program
        might be invoked faster than once a second, and seeding using
        time() produced the same result. I tried clock() but it seems
        to return 0. My program needs to be run in Linux/DOS (Watcom
	...

2008/4/21-5/2 [Computer/SW/Security] UID:49787 Activity:nil

4/21    Yahoo Instant Messenger is not encrypted. Are there chat programs
        that are a bit more secure than YIM?
        \_ what OS are you using?
        \_ What are your goals? Corporate security, or preventing your wife
           from eavesdropping on you? If you're using IM for internal company
           communication, you shouldn't be using anything where you don't
	...

2008/2/21-25 [Computer/HW/Memory, Computer/SW/Security] UID:49208 Activity:nil

2/21    Cold Boot Attacks Against Disk Encryption:
        http://www.schneier.com/blog/archives/2008/02/cold_boot_attac.html
        http://citp.princeton.edu/memory
	...

2007/9/11-13 [Computer/SW/OS/FreeBSD] UID:48016 Activity:nil

9/11    Hi does anyone else run linux/freebsd on their Desktop?
        Do you encrypt your home directory?  How does that play nice
        with hibernation/suspend?  Do you have to enter in a secret
        key when you log in?  Could you give a short summary of how
        this all works?  thank you!
        \_ I'm a FreeBSD user.  I do not encrypt my home directory
	...

2006/10/27-30 [Computer/SW/Security] UID:45013 Activity:low

10/27   Anybody tried the "PDF decryptor" or "PDF password delete" type of
        software?  I have a PDF form file that won't let me save.  I'm
        considering getting one of those type of software to unlock the
        file.  I really don't want to pay to try it out though.  Are there
        free open source PDF unlock programs?  Thanks.
        \_ I've used Elcomsoft's (of "Free Dmitry Sklyarov!" fame) PDF
	...

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www.ugrad.cs.jhu.edu/~russell/classes/enigma -> www.ugrad.cs.jhu.edu/~russell/classes/enigma/The Germans used the Enigma machine in World War II to encrypt military messages.