Create a Fingerprints of your file

350px-cpt-hashing-file-transmission-svg

How many times have you received a document or a file, and you needed to be sure that you were reading the original version of that file? Moreover, how can you trust a generic .exe, a script or whatever you receive as “attachment”?

Let me introduce a smart solution created ad hoc to check what’s behind a file.

We are talking about the MD5 algorithm!

From Wikipedia
—-
The MD5 algorithm is a widely used hash function producing a 128-bit hash value. Although MD5 was initially designed to be used as a cryptographic hash function, it has been found to suffer from extensive vulnerabilities. It can still be used as a checksum to verify data integrity, but only against unintentional corruption.

MD5 was designed by Ronald Rivest in 1991 to replace an earlier hash function MD4. The source code in RFC 1321 contains a “by attribution” RSA license.

Like most hash functions, MD5 is neither encryption nor encoding. It can be reversed by brute-force attack.
—–

For example, you can create useful “fingerprints” of your work, and then share it.

Like this one: click here and download a .mol2 (Histidine).

How you can trust that the file you are you going to download is really “the” file we are talking about?

Well, with MD5 you can always be sure of its origin, because I have assigned to it a MD5 signature:

MD5 (Histidine.mol2) = 8926aab5d9b3e9a88f642a25a50c6146

If you download it you can see by yourself what is the MD5 without opening the file!

From your terminal just type:
$ md5 Histidine.mol2
and you will get this output:
$ MD5 (Histidine.mol2) = 8926aab5d9b3e9a88f642a25a50c6146

So now you are pretty sure: this is an information strictly related to your file. Not only this, but this is a unique information!
(Yes it can reversed by a brute force attack but it isn’t easy and it waste a lot of time/computing power!)

If you add only a “space” at end of the file the hash of this file will change like this:
$ md5 Histidine.mol2
$ MD5 (Histidine.mol2) = 0084ce853a6308b4959bd711f1172b80

The fingerprints change dramatically!
from this: 8926aab5d9b3e9a88f642a25a50c6146
to this:  0084ce853a6308b4959bd711f1172b80

There isn’t anymore any relation between two strings! And we have just added a single space at end of .mol2 file!

No one could never modify this info or even try to understand what was the info behind such fingerprints.

There are a lot of applications for “signing” a file in this way, rather than just check the origin of a file: for example, you can avoid any modification to your files done by other people, because as we’ve seen every edit will dramatically change the fingerprint itself!
Of course, md5 is also one of the best option to validate any information.

Why we need a laptop to explore space chemical substance?

Daily routine

Daily routine

Computational chemistry interests several scientific communities and is expanding everyday more.


Twelve papers on the Nature
TOP 100 most cited research refers to quantum-mechanical modeling (http://www.nature.com/news/the-top-100-papers-1.16224).

Two Nobel prizes in Chemistry were awarded for foundations of computational chemistry.

The 1998 Nobel prize was assigned to Walter Kohn “for his development of the density-functional theory” and to John Pople “for his development of computational methods in quantum chemistry“.

Martin Karplus, Michael Levitt, and Arieh Warshel jointly won the Nobel prize in 2013 “for the development of multiscale models for complex chemical systems”.

Molecular modeling without experiments does not exist, but in 2016 also the opposite is true; molecular modeling is more and more frequently placed side by side with experiments. Nowadays, many applied sciences are taking advantage of molecular modeling; protein catalysis, water and air pollution, pharmaceutical chemistry, and combustion science are just few of the molecular modeling application fields.

Computational chemistry provides powerfull tools to investigate those systems that can be difficult to study by experimental means only. It can support and assist the experimental scientists in the interpretation of science research where measurements are indirect or cannot be performed due to technological limitations. Here one example of the contribution of molecular modeling to applied science.

An interesting example of molecular modeling application is the detection of organic molecules in planetary atmosphere and in the interstellar medium.
New astrochemical and astrophysical models were developed to explain and support astronomical observations. Thus, spectroscopy and computational techniques were applied together to investigate the chemical and physical processes leading to the formation of organic species in planetary atmospheres and the interstellar medium.


Quantum chemistry calculations were carried out to assess the spectroscopic and thermodynamic properties of those potentially prebiotic molecules detected in space environments. (for instance: http://pubs.acs.org/doi/abs/10.1021/ar5003285, http://pubs.acs.org/doi/abs/10.1021/acs.jpca.5b05056).

DNA pioneer Frederick Sanger dies

Frederick Sanger and a DNA model.On November 19, 2013, the English biochemist Frederick Sanger passed away. He was one among the four people to win two Nobel prizes (the others being Marie Curie, Linus Pauling and John Bardeen) and the only one to win two for chemistry; one of the most important scientists of the 20th century.
Unfortunately, his disappearance ended up in the back burner, especially on Italian media; that’s why we of MolecularModelling.org.uk think it is due to remember him in this short post. Continue reading here: Frederick Sanger

Animal testing? Aberrant!!!

Schermata 2013-09-28 alle 12.20.29

Kladderadatsch 1933 (p. 569)

“Culture Day”
Text in the cartoon: “Vivisection Forbidden”
Down: “Heil Goering (Nazi salute)”

Schermata 2013-09-28 alle 12.13.04

 

Kladderadatsch 1933 (p. 579)
“The Nightmare of the vivisectors”

 

 
In former times, it was possible to do without “animal testing”, but at what price?

Physicist Erwin Schrödinger’s Google doodle marks quantum mechanics work

Google’s latest doodle marks the birthday of Erwin Schrödinger, the Nobel prize-winning quantum physicist whose eponymous equation lies at the heart of quantum mechanics.

Born in Vienna in 1887 to a factory owner and his Austrian-English wife, Schrödinger was tutored at home as a child and went on to study theoretical physics at the University of Vienna before undertaking voluntary military service, later returning to academia to study experimental physics.

Renewed military service during the first world war broke up his studies before he was sent back to Vienna in 1917 to teach a course in meteorology.

However, it was not until his late 30s that he was to change forever the face of physics by producing a series of papers that were all written and published over the course of a six-month period of theoretical research.

By 1925, then a professor of physics at the University of Zurich and holidaying in the Alps, Schrödinger formulated a wave-equation that accurately gave the energy levels of atoms. It formed the basis of the work that would earn him the Nobel prize in physics in 1933.

In subsequent years, he repeatedly criticised conventional interpretations of quantum mechanics by using the paradox of what would become known as Schrödinger’s cat. This thought experiment was designed to illustrate what he saw as the problems surrounding application of the conventional, so-called “Copenhagen interpretation” of quantum mechanics to everyday objects.

Other work focused on different fields of physics, including statistical mechanics, thermodynamics and colour theory. In a celebrated 1944 book, What Is Life?, he turned to the problems of genetics, taking a close look at the phenomenon of life from the point of view of physics.

He died in Vienna in January 1961 from the tuberculosis that had affected him throughout his life and was buried in the western Austrian village of Alpbach.

(from The Guardian.com)

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