3 ms·

Seems like not a fault of the construction of RSA or anything else that relies on the cost of factoring, but a fault of appropriately anticipating the costs to

Seems like not a fault of the construction of RSA or anything else that relies on the cost of factoring, but a fault of appropriately anticipating the costs to break it. Useable quantum will also make crypto security more expensive and complicated. Another thing that often bothers me are claims and emphasis of how fast constructions are. This just makes it easier to brute force.

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KMag 6y ago
> Another thing that often bothers me are claims and emphasis of how fast constructions are. This just makes it easier to brute force. People generally talk about speed of encryption and decryption. You're complaining about time for bruit-force attacks. In general, there's not a linear relation between the two, and the time for initial TLS session setup matters. If it takes a year to hit amazon.com for the first time, how many people are going to visit amazon.com?
- arghwhat 6y ago
  > People generally talk about speed of encryption and decryption. You're complaining about time for bruit-force attacks. If it takes me k time to decrypt something where there are N key variations and where I can run p attempts in parallel, the maximum runtime for a brute force attack is k*N/p. Perfectly linear relationship. This is why we want large key spaces, and why algorithms needing offline brute force protection like password hashing algorithms artificially increase execution time and resource requirements to very large numbers.
  - KMag 6y ago
    > This is why we want large key spaces, This is a subset of what I'm talking about. Encryption/decryption times aren't linear with key space sizes. Force the number of required parallel instances to exceed the number of atoms on Earth, and bruit force time rapidly diverges from being linear with encryption/decryption time.
    - airhead969 6y ago
      Nit: It's spelled "brute." "Bruit" is a rumor.
  - thaumasiotes 6y ago
    > This is why we want large key spaces Yes, but large key spaces are really easy to have. The size of the key space doesn't cost you anything when you're encrypting or decrypting, but it costs the earth if you're trying to guess the key. > and why algorithms needing offline brute force protection like password hashing algorithms artificially increase execution time and resource requirements Ehhhh... this is more of a function of the fact that the password space is much smaller than it looks. Password cracking attempts generally aren't trying to exhaust the space. Instead, they're trying to guess the password based on the known properties of passwords. You start with common passwords and work your way down to iffy ones. You don't bother guessing rare passwords; there are too many of them. Rainbow tables exist, but they have sharp length limits, precisely because of the explosion-of-the-key-space phenomenon.
- airhead969 6y ago
  Strawman. There's always a legitimate user cost to attacker cost ratio, and also scaling the bike lock cost and durability to the cost of the bike.
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KMag 6y ago

> Another thing that often bothers me are claims and emphasis of how fast constructions are. This just makes it easier to brute force. People generally talk about speed of encryption and decryption. You're complaining about time for bruit-force attacks. In general, there's not a linear relation between the two, and the time for initial TLS session setup matters. If it takes a year to hit amazon.com for the first time, how many people are going to visit amazon.com?

arghwhat 6y ago
> People generally talk about speed of encryption and decryption. You're complaining about time for bruit-force attacks. If it takes me k time to decrypt something where there are N key variations and where I can run p attempts in parallel, the maximum runtime for a brute force attack is k*N/p. Perfectly linear relationship. This is why we want large key spaces, and why algorithms needing offline brute force protection like password hashing algorithms artificially increase execution time and resource requirements to very large numbers.
- KMag 6y ago
  > This is why we want large key spaces, This is a subset of what I'm talking about. Encryption/decryption times aren't linear with key space sizes. Force the number of required parallel instances to exceed the number of atoms on Earth, and bruit force time rapidly diverges from being linear with encryption/decryption time.
  - airhead969 6y ago
    Nit: It's spelled "brute." "Bruit" is a rumor.
- thaumasiotes 6y ago
  > This is why we want large key spaces Yes, but large key spaces are really easy to have. The size of the key space doesn't cost you anything when you're encrypting or decrypting, but it costs the earth if you're trying to guess the key. > and why algorithms needing offline brute force protection like password hashing algorithms artificially increase execution time and resource requirements Ehhhh... this is more of a function of the fact that the password space is much smaller than it looks. Password cracking attempts generally aren't trying to exhaust the space. Instead, they're trying to guess the password based on the known properties of passwords. You start with common passwords and work your way down to iffy ones. You don't bother guessing rare passwords; there are too many of them. Rainbow tables exist, but they have sharp length limits, precisely because of the explosion-of-the-key-space phenomenon.
airhead969 6y ago
Strawman. There's always a legitimate user cost to attacker cost ratio, and also scaling the bike lock cost and durability to the cost of the bike.

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