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The problem with a password manager is that you don't have easy access to one when you're on a different machine. A better way is to use a scheme that hashes y

The problem with a password manager is that you don't have easy access to one when you're on a different machine. A better way is to use a scheme that hashes your username, service name, and master password to generate a password. A problem is that this doesn't always comply with the arbitrary demands on your password. This is why these arbitrary demands need to die: they make the only way to securely and conveniently access accounts from different devices impossible.

wutwutwutwut 9y ago
Your suggestion is bad for a ton of reasons. For example, how do you change your password for a specific site after it had been compromised or due to normal password rotation? Another downside is that changing master password means you need to change passwords for all sites or have multiple master passwords. Another is that an attacker can use the knowledge of your password on site A to bruteforce your master password offline. And so on...
- l0b0 9y ago
  Why on earth is this being downvoted? If you've used a hashing generator for any length of time you'll know how multiple master passwords inevitably creep in. Also, when your generator no longer works because the login FQDN changes (which happens alarmingly often) you'll have all the fun of resetting your password. For no good reason. Re. portability, KeePass and its siblings are compatible with every major platform.
  - Globz 9y ago
    I have access to my password manager at all time, thanks to https://minikeepass.github.io/ https://minikeepass.github.io/ on iOS! You can even sync your database to all of your devices by storing it inside an encrypted volume for extra security.
    - kutkloon7 9y ago
      Does this also work when you use someone else's phone or computer?
- Lagged2Death 9y ago
  ...an attacker can use the knowledge of your password on site A to bruteforce your master password offline. This might be a concern if you're the victim of a state-level targeted attack. That's not a threat most of us have to deal with. Hackers aren't likely to spend a lot of effort cracking John Doe's password list; they want to steal a few million password hashes and sift out a few thousand easy or re-used ones. Your other points about the weaknesses of the scheme stand. Still, if we could get more users to use not-terrible, not-duplicated passwords, even with a flawed scheme like this, overall internet security would improve immeasurably.
  - dublinben 9y ago
    You don't need to be the victim of a state-level targeted attack. You just need to be a public figure online[0] and attract the attention of a bored hacker. [0] https://www.theverge.com/2012/8/6/3224597/mat-honan-hacked-apple-icloud-google-twitter https://www.theverge.com/2012/8/6/3224597/mat-honan-hacked-a...
    - Lagged2Death 9y ago
      I'm not super familiar with the Honan story but I recall (and quick skimming seems to confirm) that it was more about lax security policies at Apple et al, the interconnectedness of social media accounts, and social engineering than it was about reversing a computed hash or human "hashing" scheme. Did those attackers guess or compute even one password at all?
      - dublinben 9y ago
        Not in this specific instance, but they could have. And that level of scrutiny would have enabled a complete digital takeover like Honan suffered if his accounts were poorly protected by a system of passwords proposed above.
  - IncRnd 9y ago
    This is false. There are many types of targeted attacks on passwords that don't come close to including state-level actors. Divorces. Corporate Espionage. Any one of the people on Judge Judy who posted information online about their co-workers.
- kutkloon7 9y ago
  You can add something (e.g. a number) to the end to make a different password. The idea is that you have a _very_ secure master password (so bruteforcing it is not practical - to make this even more true you could hash a huge number of times instead of just once) and never change it. There is still some truth in your arguments. I'm curious what you consider a good alternative?
notzorbo3 9y ago
> hashes your username, service name, and master password Security through obscurity. You're essentially just using the same password on every site now.
- dspillett 9y ago
  Ish. If you use a sufficiently good hash function with a salt to stop rainbow table based attacks and key strengthening for good measure, then an attacker who has one compromised password of yours isn't going to be able to reverse the hash to find what your source password is so that they can generate new per-site passwords using it. That is assuming they even try: how would you know that an arbitrary string of characters was generated that way rather than just being randomly picked by a password manager? Of course all your accounts are compromised if someone knows your master password, but that is little different to an attacker getting your pass-word/-phrase for an online password manager that doesn't use some form of 2FA.
  - IncRnd 9y ago
    No. This is not a cryptographic attack on the hash but on the text that is being hashed.
    - dspillett 9y ago
      But how would the text being hashed be attacked without either attacking the hash by brute force or knowing the master password (which is likely a human factors hack, to which online password managers are similarly susceptible?
      - IncRnd 9y ago
        Using hash functions in an attack is not the same as performing a cryptographic attack against the hash function. These are two different classes of attacks, both being real-world attacks. The attack being discussed is against a suggested formula to generate passwords. From the top of the thread, "a scheme that hashes your username, service name, and master password to generate a password." Discovering the password by determining the inputs to the hash function is all that is needed. This is the case even if a different type of function is used instead of a hash. Apologies, if I gave a different impression.
kijin 9y ago
How often do you need to type passwords into a machine that you either cannot or are unwilling to sync with a decent password manager? How do you trust this machine not to record and exfiltrate everything you ever typed into it? IMO it's a Good Thing (tm) that I have to jump through hoops to access my passwords on unfamiliar machines. How does one even calculate H(username|service name|master password) on an unfamiliar machine that might not have a decent scripting language installed on it? If you asked me to do it on my father's laptop, for example, I'm gonna have to download Python first.
- Sniperfish 9y ago
  Re. the number of machines, it's something I've encountered as an obstacle from a fair proportion of people I've spoken about password managers to. I think its more a perceived issue than a real one. Just spitballing which systems I would realistically want access to passwords on, at a minimum, includes: personal desktop, personal laptop, tablet(s), cellphone(s), family (parent, sibling, in-laws, etc) computers, office desktop, office laptop. In my case (many cases?), the latter two prevent software installation, so I would need to manually type from a manager synced on my cell. Which really is no different to what is required for 2FA - just a longer character string. Overall, a some setup and synch related inconveniences but not to a damaging degree, which is why I think this is more a matter of perception - once you think through where you're typing passwords it appears less of an obstacle.
  - darylfritz 9y ago
    > the [office computers] prevent software installation, so I would need to manually type from a manager synced on my cell. I don't know about other Password Managers, but LastPass lets you access your vault using any web browser. So long as your network doesn't block the LP site, you can access your password manager from anywhere.
    - NMDaniel 9y ago
      On a similar note, Keepass can be used without admin rights with the portable version, so you can keep the portable executable along with the encrypted db file in some secure and accessible email account/web service that your network doesn't block.
deleted 9y ago
[deleted]
blowski 9y ago
Most of my passwords never need to be typed onto strange machines, so I can use 1Password with long random complex strings. If it is a password I need to type, I use diceware "Correct Battery Horse Staple" style passwords. If I don't remember the password, I always have my phone, where I can retrieve the password from 1Password. There is no relationship between my different passwords. As long as my password vault is secure, so are all my passwords. With your system, if I learn your master password and hashing mechanism, I basically have all your passwords.
- notzorbo3 9y ago
  FYI, diceware has been shown to be insecure with three words. Four is better, but also crackable by an attacker with a few thousand dollars to throw at it. Five and up is safe for the next few years.
- kutkloon7 9y ago
  True! So you have to choose a good master password and use an expensive hash. On the other hand, if you take any other approach, you place either confidence in the security of a service (1password), or you store passwords somewhere. In both cases, you have a problem when you can not retrieve the passwords anymore. If 1password is hacked or simply offline, or your phone gets stolen, you basically lost access to all services.
IncRnd 9y ago
> A better way is to use a scheme that hashes your username, service name, and master password to generate a password. A problem is that this doesn't always comply with the arbitrary demands on your password. This is a very bad mechanism to create passwords that will create severe security vulnerabilities. You are adding complexity and false-security without benefit. Passwords are a secrecy mechanism, not a formula mechanism. In your method, all one needs is the formula, then all passwords will be disclosed. The suggestion might then be to interject a secret with enough entropy into the text being hashed. But, that is no different from a secret password itself!
davchana 9y ago
I have to mine all the time, on my phone, KeepassToAndroid app. Its synced one way (PC to Phone) via dropbox, so that I can edit database only on PC.
0xffff2 9y ago
While I don't particularly like this approach, there's at least one product that does just this: https://lesspass.com/#/ https://lesspass.com/#/

wutwutwutwut 9y ago

Your suggestion is bad for a ton of reasons. For example, how do you change your password for a specific site after it had been compromised or due to normal password rotation? Another downside is that changing master password means you need to change passwords for all sites or have multiple master passwords. Another is that an attacker can use the knowledge of your password on site A to bruteforce your master password offline. And so on...

l0b0 9y ago
Why on earth is this being downvoted? If you've used a hashing generator for any length of time you'll know how multiple master passwords inevitably creep in. Also, when your generator no longer works because the login FQDN changes (which happens alarmingly often) you'll have all the fun of resetting your password. For no good reason. Re. portability, KeePass and its siblings are compatible with every major platform.
- Globz 9y ago
  I have access to my password manager at all time, thanks to https://minikeepass.github.io/ https://minikeepass.github.io/ on iOS! You can even sync your database to all of your devices by storing it inside an encrypted volume for extra security.
  - kutkloon7 9y ago
    Does this also work when you use someone else's phone or computer?
Lagged2Death 9y ago
...an attacker can use the knowledge of your password on site A to bruteforce your master password offline. This might be a concern if you're the victim of a state-level targeted attack. That's not a threat most of us have to deal with. Hackers aren't likely to spend a lot of effort cracking John Doe's password list; they want to steal a few million password hashes and sift out a few thousand easy or re-used ones. Your other points about the weaknesses of the scheme stand. Still, if we could get more users to use not-terrible, not-duplicated passwords, even with a flawed scheme like this, overall internet security would improve immeasurably.
- dublinben 9y ago
  You don't need to be the victim of a state-level targeted attack. You just need to be a public figure online[0] and attract the attention of a bored hacker. [0] https://www.theverge.com/2012/8/6/3224597/mat-honan-hacked-apple-icloud-google-twitter https://www.theverge.com/2012/8/6/3224597/mat-honan-hacked-a...
  - Lagged2Death 9y ago
    I'm not super familiar with the Honan story but I recall (and quick skimming seems to confirm) that it was more about lax security policies at Apple et al, the interconnectedness of social media accounts, and social engineering than it was about reversing a computed hash or human "hashing" scheme. Did those attackers guess or compute even one password at all?
    - dublinben 9y ago
      Not in this specific instance, but they could have. And that level of scrutiny would have enabled a complete digital takeover like Honan suffered if his accounts were poorly protected by a system of passwords proposed above.
- IncRnd 9y ago
  This is false. There are many types of targeted attacks on passwords that don't come close to including state-level actors. Divorces. Corporate Espionage. Any one of the people on Judge Judy who posted information online about their co-workers.
kutkloon7 9y ago
You can add something (e.g. a number) to the end to make a different password. The idea is that you have a _very_ secure master password (so bruteforcing it is not practical - to make this even more true you could hash a huge number of times instead of just once) and never change it. There is still some truth in your arguments. I'm curious what you consider a good alternative?

notzorbo3 9y ago

> hashes your username, service name, and master password Security through obscurity. You're essentially just using the same password on every site now.

dspillett 9y ago
Ish. If you use a sufficiently good hash function with a salt to stop rainbow table based attacks and key strengthening for good measure, then an attacker who has one compromised password of yours isn't going to be able to reverse the hash to find what your source password is so that they can generate new per-site passwords using it. That is assuming they even try: how would you know that an arbitrary string of characters was generated that way rather than just being randomly picked by a password manager? Of course all your accounts are compromised if someone knows your master password, but that is little different to an attacker getting your pass-word/-phrase for an online password manager that doesn't use some form of 2FA.
- IncRnd 9y ago
  No. This is not a cryptographic attack on the hash but on the text that is being hashed.
  - dspillett 9y ago
    But how would the text being hashed be attacked without either attacking the hash by brute force or knowing the master password (which is likely a human factors hack, to which online password managers are similarly susceptible?
    - IncRnd 9y ago
      Using hash functions in an attack is not the same as performing a cryptographic attack against the hash function. These are two different classes of attacks, both being real-world attacks. The attack being discussed is against a suggested formula to generate passwords. From the top of the thread, "a scheme that hashes your username, service name, and master password to generate a password." Discovering the password by determining the inputs to the hash function is all that is needed. This is the case even if a different type of function is used instead of a hash. Apologies, if I gave a different impression.

kijin 9y ago

How often do you need to type passwords into a machine that you either cannot or are unwilling to sync with a decent password manager? How do you trust this machine not to record and exfiltrate everything you ever typed into it? IMO it's a Good Thing (tm) that I have to jump through hoops to access my passwords on unfamiliar machines. How does one even calculate H(username|service name|master password) on an unfamiliar machine that might not have a decent scripting language installed on it? If you asked me to do it on my father's laptop, for example, I'm gonna have to download Python first.

Sniperfish 9y ago
Re. the number of machines, it's something I've encountered as an obstacle from a fair proportion of people I've spoken about password managers to. I think its more a perceived issue than a real one. Just spitballing which systems I would realistically want access to passwords on, at a minimum, includes: personal desktop, personal laptop, tablet(s), cellphone(s), family (parent, sibling, in-laws, etc) computers, office desktop, office laptop. In my case (many cases?), the latter two prevent software installation, so I would need to manually type from a manager synced on my cell. Which really is no different to what is required for 2FA - just a longer character string. Overall, a some setup and synch related inconveniences but not to a damaging degree, which is why I think this is more a matter of perception - once you think through where you're typing passwords it appears less of an obstacle.
- darylfritz 9y ago
  > the [office computers] prevent software installation, so I would need to manually type from a manager synced on my cell. I don't know about other Password Managers, but LastPass lets you access your vault using any web browser. So long as your network doesn't block the LP site, you can access your password manager from anywhere.
  - NMDaniel 9y ago
    On a similar note, Keepass can be used without admin rights with the portable version, so you can keep the portable executable along with the encrypted db file in some secure and accessible email account/web service that your network doesn't block.

deleted 9y ago

[deleted]

blowski 9y ago

Most of my passwords never need to be typed onto strange machines, so I can use 1Password with long random complex strings. If it is a password I need to type, I use diceware "Correct Battery Horse Staple" style passwords. If I don't remember the password, I always have my phone, where I can retrieve the password from 1Password. There is no relationship between my different passwords. As long as my password vault is secure, so are all my passwords. With your system, if I learn your master password and hashing mechanism, I basically have all your passwords.

notzorbo3 9y ago
FYI, diceware has been shown to be insecure with three words. Four is better, but also crackable by an attacker with a few thousand dollars to throw at it. Five and up is safe for the next few years.
kutkloon7 9y ago
True! So you have to choose a good master password and use an expensive hash. On the other hand, if you take any other approach, you place either confidence in the security of a service (1password), or you store passwords somewhere. In both cases, you have a problem when you can not retrieve the passwords anymore. If 1password is hacked or simply offline, or your phone gets stolen, you basically lost access to all services.

IncRnd 9y ago

> A better way is to use a scheme that hashes your username, service name, and master password to generate a password. A problem is that this doesn't always comply with the arbitrary demands on your password. This is a very bad mechanism to create passwords that will create severe security vulnerabilities. You are adding complexity and false-security without benefit. Passwords are a secrecy mechanism, not a formula mechanism. In your method, all one needs is the formula, then all passwords will be disclosed. The suggestion might then be to interject a secret with enough entropy into the text being hashed. But, that is no different from a secret password itself!

davchana 9y ago

I have to mine all the time, on my phone, KeepassToAndroid app. Its synced one way (PC to Phone) via dropbox, so that I can edit database only on PC.

0xffff2 9y ago

While I don't particularly like this approach, there's at least one product that does just this: https://lesspass.com/#/ https://lesspass.com/#/