Shhh.... if people hear you talk, they'll know you're dumb.
Topic: SHA-256 has no backdoors =/= Bitcoin has no backdoors - page 2. (Read 3163 times)
Shhh.... if people hear you talk, they'll know you're dumb.
Hehe. U r close to compare me with Hitler.
Uh, no.double sha2 is weaker then sha2 in some aspects.
im not sure that anyone have ever proven that sha2 hits its whole 'probability' space(2^256), if doesn't do that it will be loosing entropy by repeated applications.
more data in(a big fat block of data), means more random out. less data in(a single 256-bit sha2 hash), means less random out.
So kokjo is pointing out that nobody has proven that SHA-256 has a completely uniform probability distribution.im not sure that anyone have ever proven that sha2 hits its whole 'probability' space(2^256), if doesn't do that it will be loosing entropy by repeated applications.
more data in(a big fat block of data), means more random out. less data in(a single 256-bit sha2 hash), means less random out.
That does not imply that a second iteration makes the combined hash weaker for the reason fpgaminer pointed out. The example he used was to assume double-SHA-256 has about the same cryptographic strength as MD5. I will make a weaker assumption: assume the second hash has reduced variability because of the limited input size.
Once the attacker determines the intermediate hash in 280 time, they have a problem: they must now break the remaining 'single' hash. I suppose I should prove that later rounds don't undo the work of earlier rounds: but frankly, I don't have the time right now.
If proven, I believe this will be the end of a lot of industries based on 100% trust, like bitcoin. If bitcoin falls, the next domino will follow: Wall Streets, military top secrets all over the world, etc.
This may even fork the internet. The whole internet.
This may even fork the internet. The whole internet.
Many of you seem to be lost in translation.
SHA-256 HAS BACKDOORS.
LIKE WINDOWS OS HAS BACKDOORS. That means NSA works with Windows to plant backdoors to access any system. NSA purposely weakens software and plants backdoors in it, SHA-256 is no exception.
SHA-256 HAS BACKDOORS.
LIKE WINDOWS OS HAS BACKDOORS. That means NSA works with Windows to plant backdoors to access any system. NSA purposely weakens software and plants backdoors in it, SHA-256 is no exception.
double sha2 is weaker then sha2 in some aspects.
im not sure that anyone have ever proven that sha2 hits its whole 'probability' space(2^256), if doesn't do that it will be loosing entropy by repeated applications.
more data in(a big fat block of data), means more random out. less data in(a single 256-bit sha2 hash), means less random out.
im not sure that anyone have ever proven that sha2 hits its whole 'probability' space(2^256), if doesn't do that it will be loosing entropy by repeated applications.
more data in(a big fat block of data), means more random out. less data in(a single 256-bit sha2 hash), means less random out.
fpgaminer proved it; you are just bad at math (basing this partially on your previous thread). If you are of Middle-school age, the math may be just a little advanced for you.
Hehe. U r close to compare me with Hitler.
I mentioned 3DES because it is an example of a weak algorithm being strengthened by repeated application.
Running SHA-256 twice buys us some time if 'single' SHA-256 is found to be broken.
Running SHA-256 twice buys us some time if 'single' SHA-256 is found to be broken.
If u r not a schoolboy u should use mathematical notation instead of vague words. Try again.
If you want to confirm that Bitcoin simply runs the standard SHA-256 twice, you have only to check the source-code.
Ta, I know that.
If double SHA-2 were weaker than single SHA-2, one could simply use that construct to weaken single SHA-2. In other words, let's suppose someone discovered that double SHA-2 can be broken with 2^80 operations (instead of the usual 2^256 for a pre-image attack). Given that, anyone trying to attack SHA-2 could just, ya know, run SHA-2 on the hash they're trying to break and then perform 2^80 operations to break it and recover the original input.
Not true. Given a hash value h, if you 'recover' Care to prove?
fpgaminer proved it; you are just bad at math (basing this partially on your previous thread). If you are of Middle-school age, the math may be just a little advanced for you.
I mentioned 3DES because it is an example of a weak algorithm being strengthened by repeated application.
Running SHA-256 twice buys us some time if 'single' SHA-256 is found to be broken.
If you want to confirm that Bitcoin simply runs the standard SHA-256 twice, you have only to check the source-code.
Each arithmetic has its weakness. Even these people has to leave a small paper (never be written in direct term, just relative) about it before announces, the cracking takes long time to deal with. Even Bank-level encryption.
So, two-step just take longer before broken. This is the nature of encryption. Do you know the case of the U submarine story? Better to read again.
So, two-step just take longer before broken. This is the nature of encryption. Do you know the case of the U submarine story? Better to read again.
Hint: Running SHA-256 twice does not in any way make it less secure.
Care to prove?
With bitcoin, it is just SHA-256 twice.
Care to prove?
Double SHA-2, therefore, cannot be weaker than single SHA-2.
Doubtful, sorry.
Read the latest, whether they can crack it or not, it doesn't matter since they had backdoors planted in it.
Double SHA-256 still relies on the underlying properties of SHA-256...
With 3DES and the like, it is more than just DES three times. With bitcoin, it is just SHA-256 twice. It's quite good but the argument could be made having an alternate middle hash function would be "more" secure.
Regardless, if SHA-256 has serious issues bitcoin is the least of the problems
Why don't you read up on Tripple-DES and then restate your question?
Hint: Running SHA-256 twice does not in any way make it less secure.
Hint: Running SHA-256 twice does not in any way make it less secure.
There has been a lot of threads about Snowden, NSA and broken crypto started recently. Some guys asked what if NSA could break SHA-256, others answered that SHA-256 was analyzed by a lot of cryptomaniacs and noone has found a weakness yet... Ok, but Bitcoin uses double SHA-256. It's not that SHA-256, it's a completely different algo. What if Sha256() function applied to itself gives an outcome that correlates to the input? Like if we took f(x)=1/x and calculated f(f(5)) which is 5.
Of course, we can only speculate about this. I just want to point that it's not correctly to discuss security of Bitcoin mining algo applying well-studied features of conventional SHA-256.
Of course, we can only speculate about this. I just want to point that it's not correctly to discuss security of Bitcoin mining algo applying well-studied features of conventional SHA-256.
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