Hello,

How to decrypt a MD5 in FPC?:

http://md5decryption.com

silvioprog wrote

How to decrypt a MD5 in FPC?:

You're not supposed to. MD5 is a one way hash function. Otherwise use rainbow tables, brute force attack etc.

Once upon a time, silvioprog said:

Hello, How to decrypt a MD5 in FPC?:

MD5 is a hashing algorithm, not an encryption algorithm. There is more than one input for this algorithm which will generate the same hash, as opposed to a cipher.

Not sure if this helps or not:

http://wiki.freepascal.org/hash

2013/12/11 Ewald

Go to: http://md5decryption.com
In "Please input the MD5 hash that you would like to be decrypted:" field, put: 7db4a8dae498d1b4686ebd1f79326602
See the result in "Decrypted Text:" field.

You should read the description.
They look in a database. They don't do actual decryption.

Michael.

Please read what they write on their web page (stresses by me):

=== quote begin ===

Encrypt MD5 hash, Decrypt MD5 hash
MD5Decryption.com allows you to enter a MD5 hash and we will look *into our database*
and try to decrypt MD5. Basically it is a MD5 decrypter.

What is an MD5 hash, or MD5 Checksum?
MD5 is a 128-bit message digest function.
It is used commonly in user authentication and MD5 checksum for data integrity.

How many MD5 hashes are in our database?
*We have encrypted* more than 105,300,000 words, phrases, acronyms, etc since 2006.

=== quote end ===

So they have build themselves a database of a limited number of md5 hashes and use that to resolve your requests. MD5 is a one way hashing function. Full stop. Don't believe it? Well... I generated a hash of "wrxlbrmpf" which is d162435be814d6c6f4e1e4f077e5343d. This hash is not found in their database. Or better yet: Hash a 1GB movie and ask them to decrypt that. It would definitely be awesome if you could store a 1GB movie inside a 16-Byte hash...

Regards,
Sven

2013/12/11 Michael Van Canneyt

Ah ha... I haven't seen this detail. xD

Phew, I was thinking it would be possible to know the hidden text in a hash.

silvioprog wrote

Ah ha... I haven't seen this detail. xD Phew, I was thinking it would be possible to know the hidden text in a hash.

TBH: it seems you don't know very much about encryption. Please don't take this as an insult, but make sure you don't design/implement any password/encryption schemes if you don't know what you're doing...

That md5 online db you found isn't the only one and there's a lot you can do with GPUs and FPGAs.

Once upon a time, silvioprog said:

Yes, I've seen the site, what they probably do is a reverse lookup in a table, but it cannot be called `decryption`. Encryption is two way: an output can be converted back to the original input. This is not the case with a hashing function. Take for example a very simple function that xor's all input bytes together (with MD5 it boils down to the same, albeit a bit more complex). If I give you the output $F0, how do you know what was the original input? The answer is you don't. It could be [$80 $70] as well as it could have been [$C0 $FF $30 $FF]...

While both algorithm types (encryption and hashing) are related (the above xor example classified as a checksum, whereas xor encryption also exists), they are definitly not the same.

Once upon a time, Michael Van Canneyt said:

You should read the description. They look in a database. They don't do actual decryption.

Yep, that's what I did, I even looked at the little line advertising how much records they had in their database. Most unfortunately though it cannot be called decryption. If I would advertise a bicycle as a car to you there would also be some confusion don't you think :-)

Once upon a time, Michael Van Canneyt said:

You should read the description. They look in a database. They don't do actual decryption.

Euhm... Forget about my last reply to this mail (the one with the bicycle and the car), my brain read something different there. Sorry for the noise.

2013/12/11 Ewald

Nice explanation, thanks! (y)

Reinier Olislagers wrote

Please don't take this as an insult, but make sure you don't design/implement any password/encryption schemes if you don't know what you're doing...

Most people who /do/ know what they're doing shouldn't try to design encryption or hashing schemes, although it must be said that most World-class fsckups have resulted from key distribution and storage failures.

For the uninitiated, there's interesting info on crypto history and practice on John Savard's website http://www.quadibloc.com/

Nice !

So you obviously can compress the bible in 32 hex numbers.

Is this patented ?

-Michael