Tagged Questions

A passphrase is a longer password that typically consists of multiple words.

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2
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1answer
40 views

SSH key passphrase update and multiply locations

I have a ssh key which I use to upload code to github. the private key is located on several locations from where I upload/download data. I wonder how can I update (or expire) old keys after I update ...
4
votes
3answers
134 views

SSL Certificate - is passphrase necessary and how does apache know it?

I want to generate a Certificate Signing Request for my server and in order to do so, I first need a secure private key. When I create a private key by using openssl genrsa -des3 -out server.key 2048, ...
4
votes
2answers
188 views

XKCD-like passphrases to stdout

I'm trying to find a way to crack XKCD-like passphrases (correcthorsebatterystaple) from word dictionaries. Basically concatenate X number of words from a dictionary file. Right now it honestly ...
0
votes
0answers
52 views

Expiration / enforce change of passphrase for private ssh keys

Out of curiosity, and also to check whether this is doable at all: Is there any way using standard tools to assign an expiry date [only] to the passphrase of an ssh private key, or to enforce the ...
5
votes
3answers
174 views

How secure is this method to remember security questions?

So I found an interesting method of remembering those pesky security questions. Basically, the guy takes a hash of the question (IE what is your mother's maiden name?) and then appends his own ...
0
votes
4answers
97 views

How long does a passphrase have to be to be as secure as a random collection of letters, digits, punctuation, etc.?

If one uses a passphrase which is grammatical, such as "I put my keys under the doormat because they're safe there."... how many words (on average) must it contain to be as secure as a password with ~ ...
3
votes
2answers
268 views

Is it really “Time to add a word” if there are no tools to crack passphrases of 3 words and up?

It's "time to add a word" says Arnold Reinhold, the creator of Diceware, in his blog (3/2014). He advices to use 6 word sentences (or 5 words with one extra character chosen and placed at random) from ...
3
votes
1answer
180 views

find passphrase on encrypted ssh private key

I have an openssh encrypted private key. I don't remember the pass-phrase. I may be able to suggest words or patterns that may be in the phrase. I am looking for software that will help me recover ...
8
votes
2answers
1k views

How can a passphrase with 256 bits of entropy practically be constructed & memorized?

Quoting Wikipedia: A password with, say, 42 bits of strength calculated in this way would be as strong as a string of 42 bits chosen randomly[.] Assuming that interpretation is correct, combined ...
1
vote
1answer
173 views

how to use hash passwords to retrieve keys from keystore or access database

How do I hash the password for a keystore? How do I then use the hash to retrieve something from keystore? Similarly, how do I use a hashed password for accessing the database? I have encrypted the ...
1
vote
2answers
79 views

cleartext passphrase for keystore

How is passphrase for a keystore to be stored? we have all passwords encrypted and the key to encrypt is stored in keystore , so how is the passphrase for the keystore to be stored? in clear text? if ...
1
vote
1answer
84 views

Minimum SHA256'd UTF8 encoded passphrase length not stored anywhere

For a passphrase that is UTF8 encoded and then SHA256'd, what is the minimum length to achieve a practically collision free result? The implementation is for a 32 byte cryptocurrency ed25519 seed ...
2
votes
2answers
222 views

If I change my private key PGP passphrase, will the old private key+old passphrase work to decrypt already encrypted data?

Suppose I have a script that contains my PGP private key in plain text and requires me to manually type in the key passphrase to decrypt some data. Later, I decide that my passphrase is compromised ...
0
votes
1answer
43 views

Generate Passphrase from the data & encrypted data

right now I'm thinking about how to secure some data inside an Application... Now i have the following problem: Is it possible to generate the passpharase from a decrypted message and the same ...
0
votes
1answer
126 views

Is it a good idea to hash a string and use it as a passphrase?

Is it a good idea to hash(SHA-512/whirlpool) some simple memorable string and use it for passphrase(for LUKS/TrueCrypt container), instead of using just a string like t4k#La93Fs(5w5) as a passphrase?
6
votes
3answers
285 views

Is generating an RSA key with password and then stripping it off more secure than no password at all?

Some time ago I came across this question on SO; it asks how to remove the passphrase from an existing RSA key using a PHP equivalent to the existing openssl rss command. I've posted an answer with ...
2
votes
0answers
123 views

Passphrase generator and strength & recovery time estimator. Right strength and randomness?

Questions about the strength of pass phrases frequently popup, as does: how to generate a strong passphrase? I tried to combine both in a tool. The free tool also includes recovery time estimations ...
11
votes
3answers
1k views

Is a passphrase-protected SSH private key susceptible to a dictionary attack?

If I have a passphrase-protected SSH private key, AND if this passphrase is sufficiently random and long (say, 20-, 30-, 40-characters long, or even more!), AND if I make this private key of ...
4
votes
2answers
626 views

Would a massive blacklist of guessable passwords be useful? [duplicate]

Suggestions to make a good password all focus on creating a string that a computer (or more likely, a network of computers with multiple GPUs) can not guess. Putting a password meter for when users ...
1
vote
0answers
49 views

How can I recover the password of a TrueCrypt vlume? [duplicate]

I am trying to recover the password of a trucrypt volume. It is composed by a combination of 4 words (one invented). I remember 3 of them but not their order. Do you know any tools that cold help me ...
2
votes
1answer
343 views

What is the entropy of just 1 Diceware passphrase like my passphrase?

A 5-word Diceware passphrase gives an entropy of 7776^5 = 3E19 = 19 Bans (or ~64 bits). Apparently monster cracking systems can currently guess passphrases for MD5 at a rate of 180 billion/sec (2E11). ...
3
votes
2answers
298 views

Computing entropy for a passphrase ( minimal word length … )

Edit: 2013-05-17 . 2013-05-27 After reading first answer from Tom Leek and some docs around the web, I've begin to write some options to my tool genpassphrase.pl: $ ./genpassphrase.pl -h Usage: ...
2
votes
1answer
206 views

How vulnerable are passphrases with grammatical structure?

Imagine I create a passphrase using random dictionary words but a common grammatical structure (eg: article, noun, verb, adjective, noun). Given a pretty small dictionary of 5000 words, how vulnerable ...
3
votes
3answers
1k views

How to use USB-Stick instead of passphrase?

I wanted to know if something exists that would allow the following. Whenever I use my RSA key(when using ssh for example) I'm prompted for my passphrase. I would like to, instead of being prompted ...
3
votes
2answers
247 views

Is a random keyfile more secure than a derived key?

I'm devising an encryption layer for some proprietary cloud storage API. Basically this should act as a transparent adapter that encrypts whole binary blobs (files) on upload and decrypts them on ...
4
votes
3answers
1k views

What should I do if I type my password in the address bar, or type password in google search?

When someone accidentally types his or her password in one of the following three locations and presses enter, what should they do? username text box address bar Google search What do you suggest, ...
10
votes
5answers
3k views

Confusion: Why isn't a passhrase encrypted SSH key two factor auth?

I'm trying to figure out the best practices for accessing my devbox from a public terminal. Most sources I've found recommend protecting the box with some kind of two factor authentication, such as ...
-4
votes
7answers
814 views

Are passwords made up from concatenating a few foreign words better than shorter random characters? [duplicate]

Does it make sense to insert a foreign word into a paraphrase to mitigate against brute force? For example: "pussiMeansCatInEskimo" "caballoMeansHorse" "CatIsGatto" "SalopeMeansBitch" ...
10
votes
3answers
6k views

What's the advantage of using PBKDF2 vs SHA256 to generate an AES encryption key from a passphrase?

I'm looking at two comprable pieces of software which need to encrypt data on disk using a passphrase. One uses PBKDF2 to generate the encryption key from a passphrase, while the other uses two rounds ...
6
votes
2answers
1k views

Would an unnecessarily long password degrade performance of a WPA2 wireless network?

My friend wants to keep his home network super-secure, due to some trouble that he's had with unwelcome Wi-Fi intruders. So, naturally, he devised an ultra-long WPA2 passphrase (on the order of 100+ ...
8
votes
4answers
384 views

Will passphrases always be secure?

In a world where most people used passphrases instead of passwords, wouldn't an attack that generates a random string of words (alternating between word delimiters) be similarly effective to a brute ...
15
votes
1answer
4k views

Can a dictionary attack crack a Diceware passphrase?

Everyone knows the words used in Diceware passwords (all 6^5 = 7776 words are published) -- they're all common words. Everyone seems to know that we're not supposed to use dictionary words for ...
2
votes
4answers
553 views

passphrases - lowercase and dictionary words

Amid all the discussion about password length vs. complexity (summarized by the famous xkcd strip and the followup dicussion) I am trying to make up my mind about passphrases made up with dictionnary ...
6
votes
2answers
799 views

How should I make diceware passphrases more memorable?

I find that truly random diceware passphrase, more often than not, either contain a word that is easily misspelled or has an order that is illogical. I think there are three ways to make a diceware ...
35
votes
2answers
4k views

Pre-hash password before applying bcrypt to avoid restricting password length

Good practice is not to unnecessarily restrict password length, so that appropriately-long passphrases (perhaps 35-45 chars for 6/7 dicewords) can be used. (See e.g. Should I have a maximum password ...
9
votes
4answers
513 views

Are there state-of-the-art techniques or theory specifically for attacking passphrases over passwords?

With passphrases becoming more and more common based on length being more important than complexity, I'm assuming there must be some work going on involving techniques aimed specifically at cracking / ...