Bitcoin Forum

http://s16.postimg.org/3snukd41x/00313.jpg
http://s10.postimg.org/n3tn1taq1/0046.jpg


Try it your self:


What are you thinking ?


Edit:

Original article: http://natmchugh.blogspot.co.uk/2014/10/how-i-created-two-images-with-same-md5.html

md5sum =|= sha256sum

md5 is broken, we know that.

not all black guys' hash sum looks alike, stop being racist.

lol, but seriously, 10 seconds of googling tells me that md5 has a high collision rate.

How did you create the collision?

lmao this thread.

I'm guessing the pixel values were mutated until a collision occurred, right?

Some stuff: http://stackoverflow.com/questions/933497/create-your-own-md5-collisions

This is complete FUD. In addition, all bank vaults are now insecure since I can buy a saw and use it to saw through wood. Logical, right?

>Talks about collision and SHA256
>>shows md5 as example

Where is the logic in this? As far as I know there have been collisions in SHA256 up to round 40 I think, not afterwards.

Are you sure, sha256 will not be cracked in next 20 years?

What did Satoshi built in Bitcoin, +100 years? 100 years for sha256? My bad. for double sha256.

It doesn't seem that you understand actual cryptography very much. There is a possible ~40-round preimage attack on SHA256 (once, not twice as in mining). There are more than 40 rounds. In addition, none of these preimage attacks actually extend to be able to find a preimage that matches the correct structure of a Bitcoin coinbase+nonce, let alone over two hashings, even if they did manage to actually "break" sha256. Even if you do find a preimage that lets you get a hash matching the current difficulty, that preimage will be garbage for you as it won't be constructed to have a valid block header that will match correctly to pay you coins.

@hexafraction, Are you really thinking that this attack on md5 differ from mining of Bitcoin? I'm talking about brute-force.

Maybe in the next few years ( 20-40 years) we will have a new technology , but at the moment the "code" is strong.

Well, yes, bruteforce is what is going on this minute, at hundreds (if not thousands) of pools. At 1 exahash/sec over the world (much higher than what is today), the hash space is 1.15792089E59. Granted, a birthday problem might exist, but at the current difficulty (and 10 minutes per accepted hash) it will be sufficiently rare that it won't pose a problem. MD5 is twice-as-short, and truly broken.

Collide this then:
28fb9fbd8d2d6e97ee177c5bf1dbfd1070b677ed8908aaf041e231720aef64d2

                                                                        ____
                                                                   _||__|  |  ______   ______   ______ 
                                                                  (        | |      | |      | |      |
 28fb9fbd8d2d6e97ee177c5bf1dbfd1070b677ed8908aaf041e231720aef64d2 /-()---() ~ ()--() ~ ()--() ~ ()--()

And when the "code" won't be strong anymore, it will simply be updated. That's one of the best things about Bitcoin.

That would be the ideal scenario but since the Bitcoin network is decentralized, it might not be as easy. In such a case, a hard fork would be required. Unless every single miner switches to the new fork, you would have two different chains both calling themselves the real "Bitcoin". Once the current encryption algorithm is broken, there could even be multiple encryption algorithms vying to be the successor of SHA-256. If this happens then there would be multiple versions of Bitcoin.

I'm thinking it would make more sense if you showed collisions for SHA256 instead ::) https://bitcointalk.org/index.php?topic=120473.0

IF there was an easy way to make collisions for SHA256 right?
Because, md5 is old and only used to be a checksum hashing algorithm, it isn't made to be unique and secure.

nice post.

This thread finished with this link: https://en.bitcoin.it/wiki/Contingency_plans#SHA-256_is_broken

Looks like this is most constructive and laconic answer.


This is what called "Raisin" of Bitcoin, it is bringing the theory of cryptography's hardening-core to the real world.

An attacker with power of large country possibly unable to crack sha256 today. Than more Bitcoin will cost in price, than merrier than harder will looks cryptography embedded into it.
Who is the concerned person? Possible, it is current mass-media stars and players on this board, it is Onion-Narco-Bosses FBI, it is NSA. Because, sha256 is NSA's child. And everything apart from.

In the end, USA NSA shall not hinder the existence of coins. It is their "Alert-System", much better than cross-words in newspapers.