#Keepass. password#
In practice here, the basis is your password building blocks: the available letters.įor instance, I've just written about "95 printable ASCII characters". Without going into much details, the basis represents the available building blocks to represent a system. This is the exact reason why you can hear that people should use longer password, not complex-to-remember ones. If that value goes up (because you added one character in your password for instance), the entropy goes up which means that your password becomes stronger. This value (2 followed by 45 zeros), is directly related to the entropy we are talking about. Using only the 95 ASCII printable character, the attacker would need to try at most 2e45 passwords to correctly guess it. In practice, in the computer-security realm, it is related to the number of combinations ("states") that exist, that is to say, the number of possible passwords one has to try before guessing correctly.įor instance, take your 23-letter password. It basically represents the number of possible states reachable by a given system. The entropy is a concept coming from thermodynamics. It all depends on entropy as seen in link but also on a related concept: the basis. Your example password would essentially need to be generated completely randomly for it to have similar security (100 / log2(26) ~ 21.3 characters to get to about 100 bits: log2(26^21.3) ~ 100.12).
#Keepass. plus#
(8 x 4.2 characters, plus 7 separator characters, is 40.6.)įor comparison, this is less than twice the length of your example ireallyhatebluemountains (which clocks in at 24 characters) but, as also illustrated by the other answers, is far more secure in practice and not much more difficult to remember. (100 / 12.9 ~ 7.752, and round upwards.) Since the average Diceware word is about 4.2 characters, and you need a separator (conventionally a space) between them, this means a passphrase giving you about 100 bits of security becomes approximately 41 characters long. 100 bits worth of security using Diceware needs eight words.
#Keepass. Offline#
For a reasonably well generated passphrase using ordinary play dice, this is probably a little less simply because all values are not equally probable.įor a high-value password where an offline attack is a feasible mode of attack, such as that to a password manager, I'd probably want at least 90-100 bits worth of security. Given those assumptions, we can actually directly calculate how difficult a Diceware passphrase is to guess: For a properly generated Diceware passphrase, each word corresponds to something very close to 12.9 bits of security. They might very well even know the length of your password. Since we normally assume that an adversary knows how you generated your password or passphrase but not the exact input or end result, this means that the adversary knows that you generated it using the Diceware method and dictionary. While for reasons of physics regular play dice tend to not be perfectly fair (produce every value with equal probability), if this is a concern to you then it is possible to buy "casino dice" that are perfectly fair however, the error is likely small enough that a single extra word accounts for any reasonable reduction in dice fairness, and you can easily test your own particular dice by making a reasonable number of throws and noting how many times each value comes up (which with perfectly fair dice and a large number of throws should be 1/6 the number of throws, because the dice is six-sided). In the specific case of Diceware, you use five throws of ordinary six-sided dice to generate about 12.9 bits (log2(6^5) = log(6^5) / log(2) ~ 12.92481. Also, in Diceware, if the generated sequence of words makes sense linguistically, you are actually supposed to start over.) In proper Diceware, you use a random physical process (throwing physical dice) to gather randomness, then convert that randomness into words by looking up the numbers in a list of words.
#Keepass. how to#
(Diceware is similar to the scheme described in XKCD 936, but more explicit on how to gather the randomness. Instead, I like to recommend Diceware style passphrases.
With today's computing resources, that's just not a practically achievable goal with a simple password any longer. Traditionally, this has led to the use of weird password schemes which have tried to combine the goals of making passwords memorable as well as making them secure. Thus, you should ensure that this password has a corresponding level of security.
#Keepass. full#
This is for a rather simple, fundamental reason: this one password, together with the encrypted password database that it protects, essentially allows full access to every account for which you have credentials stored within that database. (This is irrespective of which password manager you are using.)
Let's first establish clearly what should be a common sense truth: A password manager master password is a very high value secret.
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