What exactly is a hashcode? Ateneo mathematician explains...

By -


We've often heard lawyers talk about Marlon Garcia changing the hashcode in the Transparency Server. What is this hashcode that they are talking about? And what does this hashcode have to do with our elections?

There are files which are so valuable that we want to make sure that their contents do not change. For example, a Windows installer "windows-10-installer.iso" can sometimes be corrupted when we download it from the Internet. Or the election results "results.txt" may be changed by corrupt IT practitioners to favor their candidates. In order to make sure that files like these two do not change by being corrupted during download, or by being maliciously changed to favor one candidate over another, mathematicians have invented a procedure for detecting any change in the contents of a file. This procedure is called hashing. The contents of a file are used to compute a value called hashcode or checksum or digest. Any change in the contents of the file, no matter how small, will change the value of the hashcode of the file. This change in the value of the hashcode serves as an indication that the contents of the file has changed.

For example, suppose we have the election results file whose contents are given below.

Duterte 15,970,018
Roxas 9,700,382
Poe 8,935,733
Binay 5,318,249
Santiago 1,424,520
Seneres 25,161

We can use the Android app called "Hashstamp" to compute an MD5 hashcode for this file, and we get the hashcode,

a705ec0947884537d812856ca3760a39

If we change the name of Seneres to Señeres, we get the new file,

Duterte 15,970,018
Roxas 9,700,382
Poe 8,935,733
Binay 5,318,249
Santiago 1,424,520
Señeres 25,161

and this file differs from the original one by just one character, namely the ñ character. If we use the Hashstamp app again to compute the hashcode of this file, we get,

d645ff71b248abc8401af51d21d19b22

So we see that a small change in the file produces a big change in the hashcode of the file.

Now you understand that it is wrong to say that Marlon Garcia changed the hashcode in the Transparency Server. The correct thing to say is that Marlon Garcia allegedly changed the spellings of the names of Señeres and Osmeña from the wrong spellings to the correct spellings, in the file "results_nle05092016_2000.txt", and as a result, the hashcode of that file changed, and observers saw the change, because they kept a record of the original hashcode.

The change in hashcode is an indication that the original file was changed in some way. Whether the vote counts were changed or not can not be proved by the change in hash code.

-----------------
Mathematician Pablo Manalastas as posted on Facebook:
https://m.facebook.com/story.php?story_fbid=10153741478008253&id=563973252

Comments

Post a Comment

Popular this week

Leni Robredo has become a sad mechanical puppet and an embarrassment to Filipinos

By -
Image
Guess who has taken over Leila de Lima’s place on the anti-Duterte international speaking circuit? Watch this video that Leni Robredo made for an international NGO event in Vienna tomorrow. Warning: this will REALLY make your blood boil. If you have vertigo, sit down and take a deep breath before watching. You know what’s really sickening about this video? It’s not even the lies and exaggerations that Robredo is saying about what’s going on in the Philippines and how Pinoys feel about it (as if she’s in any position to speak for the Filipino people, who mostly hate her guts). It’s the hollowness and emptiness of the way she mechanically reads from a script that obviously someone else wrote. She’s making huge claims about thousands of people being summarily killed by police, but her eyes and voice are absolutely empty of emotion or conviction. She’s just a puppet playing a role, who doesn’t even understand what she’s doing or saying, she’s just mindlessly following her owner’
Read more

Victims of drug-crazed addicts don't get 'trending' hashtags like #JusticeForKian

By -
Image
For the past few days I was doing research on a few things like I said. A new FB friend sent me a message telling me about a Dad in Dumaguete who lost his only daughter to a drug crazed addict who used 7 knives to stab her and a friend in Siquijor last April. I did the research, read up on everything and his recent "upheavals". I need not tell you all that I have no words to fully express how deeply this affects me because I am a single mom with a daughter too. His only daughter was even 3 - 4 months pregnant when she and her friend was mercilessly stabbed to death so many times by a drug addict. Nino Pinero is a professor in Siliman University. He is a coach. Given what I have read about this gentleman, he is a very compassionate man, a loving father and being a coach to youngsters - deeply loved by his students. And I would like to give him his privacy in as much as I can. 100% respect for this man. His recent "upheavals" came with the pronouncements
Read more

An open letter to CNN on their reporting on the #YolandaPH disaster in the Philippines

By -
Image
This "open letter" was found making the rounds on social media: * * * Dear Sirs: I just wanted to make some comments on the reporting of the CNN International crew here in Manila, regarding the relief efforts for the victims of super-typhoon Haiyan (which we locally call typhoon Yolanda). First, full disclosure: I am a retired Filipino executive and computer person. I was born in the Philippines and spent all my life here (save for some very short overseas stints connected with my career). I have worked with a large local Philippine utility, started up several entrepreneurial offshore software service companies (when outsourcing was not yet in vogue), and also served as the Philippine country head for a multi-billion dollar Japanese computer company. This diverse work background allows me to always see both the local and global point of view, and to see things from the very different standpoints of a third-world citizen, and a person familiar with first-world mind
Read more

Reporters Karen Lema and Manuel Mogato of @Reuters LIED about the Duterte "Hitler" quote

By -
Image
The oh-so-noble journalists are at it again, this time, with Duterte’s Hitler comment. I am no Duterte fanatic. I criticize him more scathingly than anyone when his mouth is out of line. But this time, Duterte really didn’t say anything wrong. The real culprits behind the fuss over his Hitler comment are Karen Lema and Manuel Mogato, two Filipino reporters of the Reuters news agency, who wrote this article: “ Philippines’ Duterte likens himself to Hitler, wants to kill millions of drug addicts ”. Lema and Mogato are Filipinos. There’s no way they could have misunderstood what Duterte really meant in his speech. I watched the video and this is what the President said: “Hitler massacred 3 million Jews. There are 3 million drug addicts. I’d be happy to slaughter them. At least, if Germany had Hitler, the Philippines would have ….. my victims, all criminals, to finish a problem of my country, and save the next generation.” (See for yourself here . The Hitler part is at 14:40.
Read more