Would another key work? My guess is no because we're dealing with encryption and not hashing. With hashing you can theoretically find multiple inputs that make the same output. Also I have no idea how many bits the key is. It can easily go from a "get a community driven distributed computing event to crack it" to "have you heard the one about monkeys and Shakespeare?"
Nope. Think of the key like a massively long password. Only that password is going to be able to open the file.
Yeah but in theory multiple passwords can open an account because hashing doesn't produce unique output.
Actually it does. That's literally what hashing is supposed to do.
That is what we call an attack, or a vulnerability. It isn't supposed to happen, and at the point where it does, that algorithm becomes cryptographically insecure and should not be used.
I see what you're thinking though, as it would be such an old hash that collisions must be known, right?
Well unfortunately, what we are dealing with here is encryption, not hashing, and hash collisions do not apply as an attack vector to encryption.
You could in theory try a cryptographic attack on the encrypted data but then you run into a few other problems:
you're effectively distributing a DRM bypass tool, expressly forbidden under DMCA
Attacking even the likes of RC4 takes considerable compute time on modern systems
If you do crack it, you legally can't store it, which compounds problem number 2.
Legality aside because I'm sure there's always going to be some random law that they will use (or twist) to fight this... With 3DS I remember there was a community provided cloud cracking service. I'm guessing it was either some comically weak algorithm or they found some vulnerability they were able to exploit.
But even then that's not really a good comparison because if there was some master key (I don't know the specifics) it is still physically on your 3DS and they weren't sending them around (or worse, hosting it on a store).
The situation sucks but I understand it from Valve's point of view. It's not about whether they think it is okay or not, it's about them being concerned about liability from Nintendo who are well known for protecting their IP.
Oh the shit on the 3DS was absolutely comical.
Get this: their digital licensing protection scheme was entirely client side. Which meant anybody with a hacked 3DS could just request any game they liked directly from the eShop.
A hash can take more inputs than it has outputs. By definition there have to be collisions.
...what are you even talking about? A hashing algorithm takes one data input and makes one hash from said data input.
A hash converts a large input into a small output. If a hash takes up to 128 ASCII characters and outputs 64, there will be ~10^135 collisions per output. This is completely normal and not a design flaw. It's simple math.
The strength of a cyyptographic hash function (not the only kind of hash or the only useful kind) is in not being predictable, not in avoiding collisions.
Your understanding is a little lacking.
Hash algorithms don't take an input and make it smaller. What they do is, they take an input, plug it into a mathematical formula and that outputs a string of text of fixed size, the actual size being determined by the algorithm used.
There are a few key factors people take into account while making a hashing algorithm:
collision resistance. It won't ever be possible to make it completely resistant, so they aim to make it unfeasible to do with the foreseeable future of technology. Many technologies we rely on, such as TLS, rely on hashes for verification purposes, so collision resistance is very important for that.
irreversibility. This is a big reason why it doesn't simply convert big output into small output (the other being that hashes can actually be bigger than the input data itself). Information is lost in the hashing process to the point where you can't take a hash and unhash it into the original data.
reliability. The algorithm must create the same output given the exact same data.
predictability, like you said, but only kinda. While it is true that a requirement is that an attacker must not be able to derive even part of the original data, a lot of the onus here is actually on the user to not use predictable inputs when using hashes for secure things. As said before, a hashing algorithm must give the same output when given the same input, so someone using, let's say a hashed timestamp for something secure is being a moron.
They have a fixed size output, yes. That output is effectively universally substantially smaller than the input it supports. The fact that they can also take smaller inputs as well increases the actual number of inputs, because those are in addition to the number of full length messages. The point is that the input space is a fuckton of orders of magnitude larger than the output space, which means you're literally unconditionally guaranteed that collisions have to exist.
Half your points are specific to a cryptographic hash, which isn't the only kind of hash or the only useful kind of hash, but since that's what you're talking about fine.
Collisions existing are normal. You can only avoid making finding a collision easier than finding the actual input for a password application and finding a collision with a modified hard to do for a checksum. The collisions still exist. In some applications of hashing, eg semantic hashing, collisions for similar inputs are desirable.
Yes, this is the point of a hash, but it's not hard to do.
Again, same thing. Deterministic code isn't that hard to do.
Preventing predictability is the only point for a cryptographic hash (besides being deliberately heavy to prevent brute force). If there aren't systematic flaws to make the distribution of outputs distinguishable from randomness, your cryptographic hash is going its job.
@thingsiplay They would have to know the encryption algorithm to emulate it in the first place, wouldn't they? Couldn't you just... Not emulate that part or use it to figure out how to break it easier?
If they don't emulate that part, they either can't read games, or they need to require games to be decrypted when dumped, and everyone needs a new set of ROMs
You literally cannot see the contents of the game without first decrypting it. Your internet connection is encrypted, your device is decrypting it with its known keys. You would not see the content of your Lemmy instance if your device didn't decrypt what it received.
Mostly right, but a bit misleading.
Almost every internet connection you make creates new keys. The miracle of encryption is that two people can stand in a room filled with cryptography experts and yell numbers at each other, and those two people are able to establish a secret between them that nobody else in the room can know, even though everyone else in the room has heard the conversation from the very beginning. Once you share a secret, you expand upon the secret to share more information.
@Kolanaki Cracking encryption is considered illegal I think. The only safe way I see is by providing keys to unlock, without breaking the lock. But I don't know enough about this material and just speculate around it.
Knowing the algorithm shouldn't give you advantages for any encryption algorithms with practical uses. There is no point to encrypt otherwise because someone must know the algorithm before they can implement it.
Would another key work? My guess is no because we're dealing with encryption and not hashing. With hashing you can theoretically find multiple inputs that make the same output. Also I have no idea how many bits the key is. It can easily go from a "get a community driven distributed computing event to crack it" to "have you heard the one about monkeys and Shakespeare?"
Nope. Think of the key like a massively long password. Only that password is going to be able to open the file.
Yeah but in theory multiple passwords can open an account because hashing doesn't produce unique output.
Actually it does. That's literally what hashing is supposed to do.
https://en.wikipedia.org/wiki/Hash_collision
That is what we call an attack, or a vulnerability. It isn't supposed to happen, and at the point where it does, that algorithm becomes cryptographically insecure and should not be used.
I see what you're thinking though, as it would be such an old hash that collisions must be known, right?
Well unfortunately, what we are dealing with here is encryption, not hashing, and hash collisions do not apply as an attack vector to encryption.
You could in theory try a cryptographic attack on the encrypted data but then you run into a few other problems:
you're effectively distributing a DRM bypass tool, expressly forbidden under DMCA
Attacking even the likes of RC4 takes considerable compute time on modern systems
If you do crack it, you legally can't store it, which compounds problem number 2.
Legality aside because I'm sure there's always going to be some random law that they will use (or twist) to fight this... With 3DS I remember there was a community provided cloud cracking service. I'm guessing it was either some comically weak algorithm or they found some vulnerability they were able to exploit.
But even then that's not really a good comparison because if there was some master key (I don't know the specifics) it is still physically on your 3DS and they weren't sending them around (or worse, hosting it on a store).
The situation sucks but I understand it from Valve's point of view. It's not about whether they think it is okay or not, it's about them being concerned about liability from Nintendo who are well known for protecting their IP.
Oh the shit on the 3DS was absolutely comical.
Get this: their digital licensing protection scheme was entirely client side. Which meant anybody with a hacked 3DS could just request any game they liked directly from the eShop.
A hash can take more inputs than it has outputs. By definition there have to be collisions.
...what are you even talking about? A hashing algorithm takes one data input and makes one hash from said data input.
A hash converts a large input into a small output. If a hash takes up to 128 ASCII characters and outputs 64, there will be ~10^135 collisions per output. This is completely normal and not a design flaw. It's simple math.
The strength of a cyyptographic hash function (not the only kind of hash or the only useful kind) is in not being predictable, not in avoiding collisions.
Your understanding is a little lacking.
Hash algorithms don't take an input and make it smaller. What they do is, they take an input, plug it into a mathematical formula and that outputs a string of text of fixed size, the actual size being determined by the algorithm used.
There are a few key factors people take into account while making a hashing algorithm:
collision resistance. It won't ever be possible to make it completely resistant, so they aim to make it unfeasible to do with the foreseeable future of technology. Many technologies we rely on, such as TLS, rely on hashes for verification purposes, so collision resistance is very important for that.
irreversibility. This is a big reason why it doesn't simply convert big output into small output (the other being that hashes can actually be bigger than the input data itself). Information is lost in the hashing process to the point where you can't take a hash and unhash it into the original data.
reliability. The algorithm must create the same output given the exact same data.
predictability, like you said, but only kinda. While it is true that a requirement is that an attacker must not be able to derive even part of the original data, a lot of the onus here is actually on the user to not use predictable inputs when using hashes for secure things. As said before, a hashing algorithm must give the same output when given the same input, so someone using, let's say a hashed timestamp for something secure is being a moron.
They have a fixed size output, yes. That output is effectively universally substantially smaller than the input it supports. The fact that they can also take smaller inputs as well increases the actual number of inputs, because those are in addition to the number of full length messages. The point is that the input space is a fuckton of orders of magnitude larger than the output space, which means you're literally unconditionally guaranteed that collisions have to exist.
Half your points are specific to a cryptographic hash, which isn't the only kind of hash or the only useful kind of hash, but since that's what you're talking about fine.
Collisions existing are normal. You can only avoid making finding a collision easier than finding the actual input for a password application and finding a collision with a modified hard to do for a checksum. The collisions still exist. In some applications of hashing, eg semantic hashing, collisions for similar inputs are desirable.
Yes, this is the point of a hash, but it's not hard to do.
Again, same thing. Deterministic code isn't that hard to do.
Preventing predictability is the only point for a cryptographic hash (besides being deliberately heavy to prevent brute force). If there aren't systematic flaws to make the distribution of outputs distinguishable from randomness, your cryptographic hash is going its job.
@thingsiplay They would have to know the encryption algorithm to emulate it in the first place, wouldn't they? Couldn't you just... Not emulate that part or use it to figure out how to break it easier?
If they don't emulate that part, they either can't read games, or they need to require games to be decrypted when dumped, and everyone needs a new set of ROMs
You literally cannot see the contents of the game without first decrypting it. Your internet connection is encrypted, your device is decrypting it with its known keys. You would not see the content of your Lemmy instance if your device didn't decrypt what it received.
Mostly right, but a bit misleading.
Almost every internet connection you make creates new keys. The miracle of encryption is that two people can stand in a room filled with cryptography experts and yell numbers at each other, and those two people are able to establish a secret between them that nobody else in the room can know, even though everyone else in the room has heard the conversation from the very beginning. Once you share a secret, you expand upon the secret to share more information.
@Kolanaki Cracking encryption is considered illegal I think. The only safe way I see is by providing keys to unlock, without breaking the lock. But I don't know enough about this material and just speculate around it.
Knowing the algorithm shouldn't give you advantages for any encryption algorithms with practical uses. There is no point to encrypt otherwise because someone must know the algorithm before they can implement it.