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The point of the salt isn't that it makes it take longer to break any one password. What it does is prevent you from re-using the rainbow table you generate bre

by shkkmo 5y ago

The point of the salt isn't that it makes it take longer to break any one password. What it does is prevent you from re-using the rainbow table you generate breaking one password when you break the next one. Sha1 is not a very secure/expensive hashing algorithm and thus does make it significantly cheaper to break even with a unique salt.

maccard 5y ago
> Sha1 is not a very secure/expensive hashing algorithm and thus does make it significantly cheaper to break even with a unique salt. Ok, so how long does it take to break the hash I've provided if it's not very secure?
- shkkmo 5y ago
  It's not so much "how long does it take" as it is "how much does it cost" and the answer to that really depends on what sort of compute infrastructure you have access to. Using a more appropriate hashing algorithm with a sufficient cost factor can massively increase the amount of compute needed. Preventing the re-use of that computational effort on additional users is why unique salts are important.
  - maccard 5y ago
    > It's not so much "how long does it take" as it is "how much does it cost" So the answer is "It's too expensive to figure out in practice, unless you're being explicitly targetted by someone with nation state level credentials?", i.e. it's pretty much fine? > Using a more appropriate hashing algorithm with a sufficient cost factor can massively increase the amount of compute needed. But by the sounds of it, SHA1 is more than enough (given that nobody here is willing to brute force the hash I shared above?) > Preventing the re-use of that computational effort on additional users is why unique salts are important. The person who "cracked" my first hash found it in a list of passwords which was actually gotten from a plain text dump 15 years ago. That wasn't found by reversing a hash, so the compute wasn't reused. You are right that once it's cracked, it's cracked and that's that, but if your password _isn't_ cracked it's moot whether it's hashed with SHA1 or something more secure, as per above?
    - deleted 5y ago
      [deleted]
    - theneworc 5y ago
      >But by the sounds of it, SHA1 is more than enough (given that nobody here is willing to brute force the hash I shared above?) SHA1 is "more than enough" for this specific interaction in which you chose a complex password and/or your only opponents are unmotivated/non-incentivized HN commenters that don't have a password cracker at their immediate disposal. That doesn't mean anything outside of this context. If your opponent was a motivated hacker with dedicated password cracking machines (which do not require anything even close to a nation-state budget, btw), your SHA1 hash would be much more likely to be cracked. If you were a specific target of a hacker group, such as an employee of a company that is being targeted by an attack or someone known to have a BTC wallet with $10 million in it, your SHA1 hash would be much more likely to be cracked. If your password was a relatively simple phrase like "dog$aregreat2019", like the vast majority of user passwords are, it would almost certainly be cracked. SHA1 is not even anywhere close to "enough" for general password hashing use. Don't think otherwise just because a couple of random HNers failed your little game. edit: The premise of your "challenge" is also not equivalent to the goals of most hackers. Unless you are a specifically known and prioritized target (because you're a celeb, VIP, wealthy person or something like that), the goal of a hacker is not to take one specific hash and crack it, because the success of that will depend a lot on the complexity of your password. The goal of most hackers in a breach like this Twitch one is more like "just throw it all at the wall and see what sticks". They take a massive database of thousands of hashes and spend a few hours to see what can be cracked, taking advantage of the fact that while some people may have complex passwords, most do not. After a few hours, maybe they crack 90% of the SHA1 hashes in a leak. Maybe your password was complex enough that it was in the 10% that wasn't cracked; good for you, but just because your password remained uncracked doesn't mean SHA1 is "enough". The hackers still got the other 90%.
      - ghostway-chess 5y ago
        But you shared a hash of an uncommon password. We probably have the salt (probably somewhere in the code) and people dont use password managers. So rainbow tables are enough. Oh, I thought the first sentence was you and not quoted. Agreed with the above
thaumasiotes 5y ago
> What [a password salt] does is prevent you from re-using the rainbow table you generate breaking one password when you break the next one. Your idea of what a rainbow table is appears to be unrelated to what a rainbow table actually is. A rainbow table is prepared in advance, not generated in the process of cracking an individual password.

by shkkmo 5y ago

maccard 5y ago

> Sha1 is not a very secure/expensive hashing algorithm and thus does make it significantly cheaper to break even with a unique salt. Ok, so how long does it take to break the hash I've provided if it's not very secure?

shkkmo 5y ago
It's not so much "how long does it take" as it is "how much does it cost" and the answer to that really depends on what sort of compute infrastructure you have access to. Using a more appropriate hashing algorithm with a sufficient cost factor can massively increase the amount of compute needed. Preventing the re-use of that computational effort on additional users is why unique salts are important.
- maccard 5y ago
  > It's not so much "how long does it take" as it is "how much does it cost" So the answer is "It's too expensive to figure out in practice, unless you're being explicitly targetted by someone with nation state level credentials?", i.e. it's pretty much fine? > Using a more appropriate hashing algorithm with a sufficient cost factor can massively increase the amount of compute needed. But by the sounds of it, SHA1 is more than enough (given that nobody here is willing to brute force the hash I shared above?) > Preventing the re-use of that computational effort on additional users is why unique salts are important. The person who "cracked" my first hash found it in a list of passwords which was actually gotten from a plain text dump 15 years ago. That wasn't found by reversing a hash, so the compute wasn't reused. You are right that once it's cracked, it's cracked and that's that, but if your password _isn't_ cracked it's moot whether it's hashed with SHA1 or something more secure, as per above?
  - deleted 5y ago
    [deleted]
  - theneworc 5y ago
    >But by the sounds of it, SHA1 is more than enough (given that nobody here is willing to brute force the hash I shared above?) SHA1 is "more than enough" for this specific interaction in which you chose a complex password and/or your only opponents are unmotivated/non-incentivized HN commenters that don't have a password cracker at their immediate disposal. That doesn't mean anything outside of this context. If your opponent was a motivated hacker with dedicated password cracking machines (which do not require anything even close to a nation-state budget, btw), your SHA1 hash would be much more likely to be cracked. If you were a specific target of a hacker group, such as an employee of a company that is being targeted by an attack or someone known to have a BTC wallet with $10 million in it, your SHA1 hash would be much more likely to be cracked. If your password was a relatively simple phrase like "dog$aregreat2019", like the vast majority of user passwords are, it would almost certainly be cracked. SHA1 is not even anywhere close to "enough" for general password hashing use. Don't think otherwise just because a couple of random HNers failed your little game. edit: The premise of your "challenge" is also not equivalent to the goals of most hackers. Unless you are a specifically known and prioritized target (because you're a celeb, VIP, wealthy person or something like that), the goal of a hacker is not to take one specific hash and crack it, because the success of that will depend a lot on the complexity of your password. The goal of most hackers in a breach like this Twitch one is more like "just throw it all at the wall and see what sticks". They take a massive database of thousands of hashes and spend a few hours to see what can be cracked, taking advantage of the fact that while some people may have complex passwords, most do not. After a few hours, maybe they crack 90% of the SHA1 hashes in a leak. Maybe your password was complex enough that it was in the 10% that wasn't cracked; good for you, but just because your password remained uncracked doesn't mean SHA1 is "enough". The hackers still got the other 90%.
    - ghostway-chess 5y ago
      But you shared a hash of an uncommon password. We probably have the salt (probably somewhere in the code) and people dont use password managers. So rainbow tables are enough. Oh, I thought the first sentence was you and not quoted. Agreed with the above

thaumasiotes 5y ago

> What [a password salt] does is prevent you from re-using the rainbow table you generate breaking one password when you break the next one. Your idea of what a rainbow table is appears to be unrelated to what a rainbow table actually is. A rainbow table is prepared in advance, not generated in the process of cracking an individual password.