Create a Fingerprints of your file

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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
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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.
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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.

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?

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