# Eikonal Blog

## 2011.03.29

### Broken patents system

Filed under: it, opression, patents — Tags: , , — sandokan65 @ 13:50

Related here: One more example of reactive social role of patent system – https://eikonal.wordpress.com/2010/07/09/one-more-example-of-reactive-social-role-of-patent-system/ | Lawsuits in mobile space – https://eikonal.wordpress.com/2010/10/08/lawsuits-in-mobile-space/

## 2011.03.28

### Universal calendars

Filed under: mathematics — Tags: — sandokan65 @ 16:59

According to Daniel Zwillinger (“Standard Mathematical Tables And Formulae”; 31st ed; 2003; Recipe 10.3.2, but formula 10.3.1) the specific date maps to the following day of the week (in the Gregorian calendar):

$W = \left(k + [2.6 m -0.2] - 2 C + Y + \left[\frac{Y}4\right] + \left[\frac{C}{4}\right]\right) \ (mod \ 7)$

Here:

• W = day of the week (0=Sunday to 6=Saturday)
• k = the day in the month (= 1 to 31)
• m = the month (1=March to 12=February)
• C = century minus one (1997 $\rightarrow C=19$, 2005 $\rightarrow C=20$)
• Y = the year inside century, where the years begining is march 1st (so, 1997 maps to $Y=97$ except for January and February when it goes to $Y=96$
• and $[...]$ is the floor function (the largest integer part of the enclosed real number).

For example, today is March 29th, 2011. That would be:

• The day’s order number inside this month: $k=29$
• This month is, according to Roman counting, the first one in the year: $m=1$
• The year inside the century is $Y=11$ (since it is past February)
• The century is 21st, so $C=21-1 = 20$
• So: $[2.6 m -0.2] = [2.6 -0.2] = [2.4] = 2$, $[Y/4] = [11/4] = [2.25] = 2$, $[C/4] = [20/4] = 5$
• and $W = \left(29 + 2 - 2 \times 20 + 11 + 2 + 5\right) \ (mod \ 7) = (49-40) \ (mod \ 7)$ $= 9 \ (mod \ 7) = 2$ i.e. today is Tuesday (correct).

## 2011.03.15

### Atlantis – or not

Filed under: history, past — Tags: — sandokan65 @ 14:44

## 2011.03.11

### PAM (Pluggable Authentication Modules)

Filed under: infosec, unix — Tags: , , — sandokan65 @ 16:14

## Roles of PAM files

• /etc/pam.conf – all-in-one configuration file for early versions of PAM. It may still be used in some modern versions.
• /etc/pam.d/ – directory containing configurations files for each of separately configured program
• /etc/pam.d/other – the default config file regulating all files that do not have their own separate PAM config file
• /etc/pam.d/system-auth
• /etc/pam.d/sshd
• /etc/pam.d/su
• /etc/pam.d/gdm – the GNOME Display Manager PAM file.
 #%PAM-1.0 auth requisite pam_nologin.so auth required pam_env.so readenv=1 auth required pam_env.so readenv=1 envfile=/etc/default/locale auth sufficient pam_succeed_if.so user ingroup nopasswdlogin @include common-auth auth optional pam_gnome_keyring.so @include common-account session [success=ok ignore=ignore module_unknown=ignore default=bad] pam_selinux.so close session required pam_limits.so @include common-session session [success=ok ignore=ignore module_unknown=ignore default=bad] pam_selinux.so open session optional pam_gnome_keyring.so auto_start @include common-password 

## Syntax of config files

Each line has format:

module-type   control-flag   module-path   arguments

## PAM modules

• pam_deny.so module –
• pam_permit.so module –
• pam_warn.so module – used to interface to syslog

## 2011.03.09

### Privacy articles

• Report: “Dispelling the Myths Surrounding De-identification” (Anonymization can still work) by Lauren Weinstein (Lauren Buzz; 2011.06.16) – http://bit.ly/lbH5PE by Information and Privacy Commissioner of Canada [PDF]
“Recently, the value of de-identification of personal information as a tool to protect privacy has come into question. Repeated claims have been made regarding the ease of re-identification. We consider this to be most unfortunate because it leaves the mistaken impression that there is no point in attempting to de-identify personal information, especially in cases where de-identified information would be sufficient for subsequent use, as in the case of health research. The goal of this paper is to dispel this myth – the fear of re-identification is greatly overblown. As long as proper de-identification techniques, combined with re-identification risk measurement procedures, are used, de-identification remains a crucial tool in the protection of privacy.”
• AOL search data scandal (WikiPedia) – http://en.wikipedia.org/wiki/AOL_search_data_scandal
• “What the know” series of articles (The Wall Street Journal) – http://online.wsj.com/public/page/what-they-know-digital-privacy.html
• “The privacy covenant is an illusion: How to regain control” by Chad Perrin (Tech Republic; 2011.04.18) – http://www.techrepublic.com/blog/security/the-privacy-covenant-is-an-illusion-how-to-regain-control/5351?tag=nl.e036

Related pages here: Privacy and digital liberties – https://eikonal.wordpress.com/2010/11/01/privacy-and-digital-liberties/|Personal computer security – https://eikonal.wordpress.com/2011/02/28/personal-computer-security/ | Online privacy tools – https://eikonal.wordpress.com/2010/12/25/online-privacy-tools/ | Unending stream of Facebook privacy news – https://eikonal.wordpress.com/2010/11/22/unending-stream-of-facebook-privacy-news/ | TSA folies – https://eikonal.wordpress.com/2010/11/16/tsa-folies/

## Arthur Schopenhauer

• “Die Kunst, Recht zu behalten” = “The Art Of Controversy”:

### Taboo

Filed under: censorship, opression, propaganda, society — Tags: , , , — sandokan65 @ 12:26
• “What You Can’t Say” by Paul Graham (2004.01) – http://paulgraham.com/say.html
• “The Motion Picture Production Code of 1930 (Hays Code)” (in Reformation of the Arts and Music) – http://www.artsreformation.com/a001/hays-code.html
• “What You Can’t Say Will Hurt You” By Geoffrey R. Stone (NYT; 2005.08.15) – http://www.archub.org/stone.txt
• “A Civic Duty to Annoy” by Wendy Kaminer (1997.09) – http://www.archub.org/civicduty.txt
• “Stanley Milgram: The Perils of Obedience” (at Paul Graham’s web site) – http://paulgraham.com/perils.html
• “Mark Twain: Corn-pone Opinions” (at Paul Graham’s web site) – http://paulgraham.com/cornpone.html
• “A New Blacklist for “Excuse Makers” ” (FAIR; 2005.07.27) – http://www.fair.org/index.php?page=2598
New York Times columnist Thomas Friedman has urged the U.S. government to create blacklists of condemned political speech–not only by those who advocate violence, but also by those who believe that U.S. government actions may encourage violent reprisals. The latter group, which Friedman called “just one notch less despicable than the terrorists,” includes a majority of Americans, according to recent polls.
Those who think Iraq War sparks terror are “despicable,” says Friedman
• book “The Ten Things You Can’t Say In America, Revised Edition” by Larry Elder (Amazon) – http://www.amazon.com/exec/obidos/tg/detail/-/0312284659/
• “Stratagem XXXII” from “The Art Of Controversy” by Arthur Schopenhauer – http://coolhaus.de/art-of-controversy/erist32.htm
If you are confronted with an assertion, there is a short way of getting rid of it, or, at any rate, of throwing suspicion on it, by putting it into some odious category; even though the connection is only apparent, or else of a loose character. You can say, for instance, “That is Manichaeism” or “It is Arianism,” or “Pelagianism,” or “Idealism,” or “Spinozism,” or “Pantheism,” or “Brownianism,” or “Naturalism,” or “Atheism,” or “Rationalism,” “Spiritualism,” “Mysticism,” and so on. In making an objection of this kind, you take it for granted (1) that the assertion in question is identical with, or is at least contained in, the category cited – that is to say, you cry out, “Oh, I have heard that before”; and (2) that the system referred to has been entirely refuted, and does not contain a word of truth.

## 2011.03.04

### HTML5

Filed under: tools, web tools — Tags: , , , , , — sandokan65 @ 13:47

## 2011.03.02

Filed under: unix — Tags: , , — sandokan65 @ 14:20

## AIX

Related here: Unix tricks – https://eikonal.wordpress.com/2011/02/15/unix-tricks/

### Skype went malware ways

Filed under: antimalware, infosec — Tags: , — sandokan65 @ 12:22

Since recently Skype started peddling its new versions in a forceful way by downloading the update to the users PC, and then throwing the large update notification window to the desktop forefront. It is not possible to disable this behaviour. It is so annoying that I will probably switch to some alternative provider of online voip.

## 2011.03.01

### MS Windows Registry transversal by Cygwin

Filed under: cygwin, unix, windows — Tags: , , , — sandokan65 @ 12:08

This may be an old thing, but it is new to me. Today I accidentally discovered that from inside Cygwin (i.e.e the Bash shell) one can transverse the Windows Registry. For example, one can list the content of HKEY_CLASSES_ROOT hive by simply typing:

 ls -la /proc/registry/HKEY_CLASSES_ROOT/ 

with partial output:

 total 0 dr-xr-x--- 5 Administrators SYSTEM 0 Apr 26 2010 * dr-xr-x--- 7342 Administrators SYSTEM 0 Feb 18 10:32 . dr-xr-xr-x 8 thisuser mkgroup-l-d 0 Mar 1 12:02 .. dr-xr-x--- 3 Administrators SYSTEM 0 Feb 16 2010 .123 dr-xr-x--- 2 Administrators SYSTEM 0 Feb 3 2009 .323 dr-xr-x--- 3 Administrators SYSTEM 0 Feb 3 2009 .386 dr-xr-x--- 2 Administrators SYSTEM 0 Nov 17 2009 .3g2 dr-xr-x--- 2 Administrators SYSTEM 0 Nov 17 2009 .3gp dr-x------ 2 thisuser ???????? 0 Jun 7 2010 .5vw dr-x------ 4 thisuser ???????? 0 Nov 17 2009 .A1wish dr-x------ 2 ???????? None 0 Aug 5 2009 .ARC dr-x------ 2 ???????? None 0 Aug 5 2009 .ARJ dr-xr-x--- 3 Administrators SYSTEM 0 Feb 4 2009 .AddIn dr-x------ 3 ???????? ???????? 0 Aug 7 2009 .AudioCD dr-x------ 2 ???????? None 0 Aug 5 2009 .B64 dr-x------ 2 ???????? None 0 Aug 5 2009 .BHX dr-x------ 2 ???????? ???????? 0 Aug 7 2009 .CTT dr-xr-x--- 3 Administrators SYSTEM 0 Feb 3 2009 .DeskLink dr-x------ 3 ???????? ???????? 0 Aug 7 2009 .Folder dr-xr-x--- 2 Administrators SYSTEM 0 Feb 3 2009 .JSE dr-x------ 2 ???????? None 0 Aug 5 2009 .LZH dr-xr-x--- 3 Administrators SYSTEM 0 Feb 3 2009 .MAPIMail dr-x------ 2 ???????? None 0 Aug 5 2009 .MIM ... 

Such feature is available in Microsoft’s PowerShell for several years now, but I did not know that this exists in the Cygwin’s Bash. When was this feature incorporated in the Cygwin? Was it inspired by PowerShell?

Also, the same feature works for /proc/registry32/ and /proc/registry64/