Steganography on images

This week I come across some theories about steganography on images to hide secret text. The method is to change the least signifcant bit to its reverse value. Consider a true colour image with 24 bit colour depth, altering least significant bit will cause a slight change in colour but this can hardly be detected by human eyes. How much information can an image carry ? An image might have 320 x 480 pixels and six pixels each giving out a single bit can contribute to a single ASCII text character. That is to say, an 320 x 480 image can store up to 25600 text characters which should be quite sufficient to spread secret information from one machine to another.

Comat 28 Class Today

Today evening is the launch of Combat 28 in all 7 clubs of California Fitness Center. I intend to attend the 1st class by Yvonne at Causeway Bay starting at 6:30 pm and then proceed to Wan Chai to continue the 2nd class by Stephaine. I can not finish all the 9 tracks in the first class as I need to rush to Wan Chai. I think I will have to leave after finishing the Muay Thai track.

Tomorrow I agree to meet Kay in Central for the class conducted by Michelle D. Wooo... I don't know if my physical strength can sustain three rigorous exercises in 2 days.

SMTP Daemon can not restart

A couple of days ago, my email server crashed and it could not be restarted. The reason was unknown. I had no other method to restore it but had to perform a remote reboot. Hopefully everything worked fine.

Actually, I had not rebooted my server for over 200 days. When running programs are closed, there is no guarantee that residual memory occupied could be 100 % released. Days after days, there is less and less usable memory. It is a good idea to reboot server after a certain time, say one or two months.

Launch of BodyCombat 28

Combat 28 training class will be launched on evening of 12 May (Friday) at the 7 California centers almost at the same time. Frankly, I don't like to have launch class of new release on Friday evening. It is because members might not be able to free themselves from their duties. Saturday and Sunday are the perfect time for launch. I hope the timing of launch class should be considered carefully in the next release.

BTS Forum

BTS is a well-known forum is for instructors, participants and anyone interested in the Les Mills programs. I joined it a couples of days ago.

In the Forum, I see big names of some international renowned trainers. There are not many people from Hong Kong. I counted only 5. As a matter of courtesy, I have dropped them a message to introduce myself.

I gained a lot of new knowledges about Les Mills exercise. For example, the name BodyBalance is not used in USA, rather, it is called Body Flow.

Could I be an active member in the Forum ? I don't know yet !

New banner in blog template

The recent Blue Frog Community Program attracted me, the purpose of which is to unite a large group of people (about half million) together to fight back against spammers. These people set up a do-not-intrude list. If spammers try to send spam email to any of the email account, a large number of PCs will send DD0S to the spammer servers or web hosts.

For more than a year, I have not added any new banner into my blog template. I decided to add Blue Frog banner as part of my blog template. The aim, of course, is to let more people know the Blue Frog Community Program. I particulary like their slogan, " Stop filtering spam, start deterring spammers!"

My first visit to Pakpolee Club

Today, Pakpolee Club was opened to use by members of the California Fitness Cente. I made a tour aroud for about 15 minutes. The changing rooms are at the top floors. Of course, this is not convinient as we have to walk upstair for so many floors. Actually, this comes as no surprise to me.
For group X facilities, the cycling studio is ok. What I dislike much is the size of the multi-purpose studio. It is so small that it can not accomodate 50 people together. It would be very crowded for bodybump or bodycombat classes. Unfortunately, the management of California Fitness Center is not aware of this.

storing maps on PSP

I need to go to Ma On Shan Sports Center tomorrow morning. I don't know the location and how to get there. Logically, average Hong Kong people will browse centamap.com and print a hard copy of the location. But my situation is different. I don't have a B&W or colour printer at home. What I can do is to save the image on to my PSP and bring along the PSP. Woo..... I have save atb least one paper by using electronic means to store something of temporary use.

California Fitness Center - Mongkok Pakpolee Club

The 7th club of California Fitness Center at Mongkok Pakpolee Centre will be opened on 1st May. I heard that there will be 8 floors and the total club size is only 30,000 sq feet. We can imagine how small each floor will be. Walking stair 8 floors is not fun at all. Let's hope there will be lifts to serve different floors. Wait ! I recall that there are two lifts in Tsim Sha Tsui Center but somehow they are disabled in order to allocate more space for placing training equipment and facilities. This is completely crazy.

Election Committee - IT Subsector

In response to the Government call, I have registered myself as a voter for the Election Committee Subsector for the Information Technology Functional Constituency. Amongst the 800 members in the Election Committee, 20 of them will come from the Information Technology Functional Constituency. In the last election, only 5 % of the local IT workforce registered as voters. This is far disappointing. Though I do not have a vote on the CE election, I hope the elected members from the IT sector will make the right choice and pick the right candidate.

One-to-one personalized email marketing service

In an attempt to lure me to register new domain name under .name TLD, godaddy.com sent me an HTML email with the following image embedded:




It tried to put my surname in the banner image and the image is only applicable to me. This is a typical case of harnessing one-to-one personalized email marketing service. The recipient, of course, will be much impressed.

Sender Policy Framework (SPF)

I checked that I have not written anything in my blog about sender policy framework (SPF). Well, I'd better do so otherwise I might forget the whole concept later on. In fact, this is a service for receiving mail server to authenticate the sender in the "mail from" field. It works this way. Suppose a spammer tries to use the sender email address as xyz@aol.com, the receiving mail server will interrogate the domain records of aol.com. There is a string of text telling which IP addresses can use the domain aol.com (sender policy). The spammer will be using an IP addresses not in the domain records of aolc.com and the receiving mail server will reject the email.

The good news is that all existing DNS software packages can support additional text strings for implementing SPF. However, receiving mail servers need to be upgraded to perform the SPF interrogation.

Here below is the IP addresses that can be associated with the domain aol.com:

> set type=txt
> aol.com

Non-authoritative answer:
aol.com text = "v=spf1 ip4:152.163.225.0/24 ip4:205.188.139.0/24 ip4:205.188.144.0/24 ip4:205.188.156.0/23 ip4:205.188.159.0/24 ip4:64.12.136.0/23 ip4:64.12.138.0/24 ptr:mx.aol.com ?all"
aol.com text = "spf2.0/pra ip4:152.163.225.0/24 ip4:205.188.139.0/24 ip4:205.188.144.0/24 ip4:205.188.156.0/23 ip4:205.188.159.0/24 ip4:64.12.136.0/23 ip4:64.12.138.0/24 ptr:mx.aol.com ?all"

Right Hand Side Blacklist

I am using DNS-based Blacklist (spamhaus.org and spamcop.net) to filter out spam emails. The blacklist systems are based on IP addresses which somebody might call it Left Hand Side Blacklist (LHSBL). There is another kind of DNS-based blacklist system that check domain names instead of IP address. The name Right Hand Side Blacklist (RHBL) is therefore established as we look at a DNS record, the right hand side always denotes a domain while the left hand side tells the IP address associated.

Suppose an email has the domain name "example.com" in the "MAIL FROM:" field and the server dsn.rfc-ignorant.org is where we want to lookup. We will look at example.tld.dsn.rfc-ignorant.org, and if the IP address 127.0.0.2 is returned, the domain name "example.com" is blacklisted.

Ha... I have gained some new knowledge in the area of DNSBL.

CD album will be history

In late 70's, CD was invented to replace grtamophone record. Now that everyone uses portable players such as MP3 or ipod, purchase of music online will soon make CD album redundant. This is a logical evolution and there are some benefits to consumers. They can nuy individual songs they like instead of buying all the songs in an entire CD album. Without CD, the world uses less plastic and less packing materials. Good to the environment.

Everyone needs an FTP Server

Yesterday, I needed to transfer 5 GB of files from one PC to another. The usual and logic way to do this is to hook up to an Ethernet switch and share the required folders for the PC on the same network to retrieve. However, things did work that work because of SP2 personal firewall settings.

I tried a work around solution. I started an FTP server (Cerberus) on the PC holding the 5GB files that needed to be transferred out. The other PC run SmartFTP client to download the files. This seemed to be a better solution than sharing folders over the same network segment.

For those that have more than 2 PCs at home, they should have an FTP server to circumvent problem in sharing folders.

Richter scale on email volume

SenderBase Network sets up a global email traffic monitoring network. In quantifying email volume, the Richter scale used to measure earthquakes is applied to message volume calculated using a log scale with a base of 10. The maximum theoretical value of the scale is set to 10, which equates to 100% of the world's email message volume (approximately 10 billion messages/day).

By checking the IP address of our company's outgoing mail server, our Richter magnitude is 1.9. This can be translated to 7900 outbound email messages per day. Hey....., this is a rather interesting concept.

bodycombat tracks

There are about 300 tracks in Les Mills Bodycombat (BC) series. I try to list the 10 most favorite tracks. Here is my choice in the order of preference :

Greensleevs : BC19 – 03
Ludwig is alive : BC17 -8
Symphony No. 9 : BC13 - 8
Razzia : BC18 - 08
Bagpipes : BC26 - 04
Excalibur : BC11 - 5
Guita Damage : BC26 - 02
Stuck on you : BC23 - 01
I like chopping : BC19 - 01
My Sharona : BC10 -5

By the way, some combat fans do not know who Ludwig is. Ludwig is the given name of the famous German musician Beethoven. His full name is Ludwig van Beethoven.

60GB ipod player

Finally, the storage space of my 4GB ipod Mini has all exhausted. I have no means to expand the storage but to buy another ipod player. The logical choice is 60GB ipod which can supports video playing and viewing of photos. It costed me $3100. This time it is not possible for me to consumer all the available storage space. Should I consider to use the available space to store my personal files. Thats a good idea indeed !

HKIX Looking Glass lookup

Sometime ago, I was able to tell my colleagues the IP address prefixes advertizied by AS 9269 which is owned by a Hong Kong ISP. At that time, I relied upon www.fixedorbit.com to use the AS lookup tool to find the prefixes.

In fact, HKIX provides a looking glass service that we can look for the IP prefixes advertized or received through a particular AS number. "Looking glass" is an interesting term. I am still looking for the exact defintion meaning in the networking world.

.xxx top level domain

Some wise people put forward to ICANN the idea of creating the .xxx top level domain for adult and porn sites. The motive was good. Parents would not allow children to access domains ending with .xxx. I don't see why ICANN needs to reject the proposal.