Passwords are secret keys which human beings can memorize.

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291 views

How can one share information using the 'host-proof' paradigm?

I am attempting to make a web-based secure password management and sharing utility, both as an academic exercise and to fully understand and feel safe about using it. I really like the idea of a ...
2
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2answers
172 views

How can I store a combination of multiple pass phrases?

Let's assume we have 2 phrases, one is the real password from a user, and the other is generated from the real password and almost impossible to guess. You would need both to authenticate a user. What ...
3
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2answers
493 views

Passwords with same SALT. What does this mean?

If the same SALT is used for many passwords on a Linux server, in what way is that a security risk? Does the mean, that a user (which can change his own password) can calculate other users passwords? ...
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4answers
5k views

Can you help me understand what a cryptographic “salt” is?

I'm a beginner to cryptography and looking to understand in very simple terms what a cryptographic "salt" is, when I might need to use it, and why I should or should not use it. Can anyone offer me a ...
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1answer
1k views

Store user passwords in database using Java Application

I want to store user's password details in Database. My project is in Java. I want to know the best way of storing passwords and other important information like user data.
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2answers
1k views

Use of salt to hash a password

In a few implementations of hashed passwords, I have seen that the length of the random salt is chosen to be, say, 10 or "some constant". Is there any specific reason why the salt is chosen to have a ...
5
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5answers
253 views

In storing passwords in a database should I use a per-application salt in addition to a per-secret salt?

Assuming that the salts are sufficiently long (16 random chars) is there any advantage in using a per-application salt in addition to a per-secret salt when storing hashed passwords in a database? ...
1
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1answer
130 views

How is the password sent across for verification?

I am familiar with Challenge-Response Authentication scheme. However I would like to know actual message content sent between client and server for 1 way authentication, over an insecure channel. ...
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4answers
2k views

How can rainbow tables be used for a dictionary attack?

I'm putting together a password policy for my company. I very much want to avoid requiring complex passwords, and would much rather require length. The maximum length I can enforce is 14 characters. ...
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2answers
1k views

How exactly would someone crack a private key passphrase? [closed]

Lets say for a PGP/GPG pair with a passphrase.
3
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2answers
266 views

If Bob steals Alice's private key, how exactly would he read her encrypted documents?

So Bob grabs Alice's secret key when she isn't looking and her encrypted files, doesn't he need to know her passphrase to read her files? What I am reading is that no he does not need it but as far ...
26
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6answers
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Is there a secure cryptosystem that can be performed mentally?

I, myself, do not plan on getting into a situation where I would be unable to use a computer in order to communicate securely. However, I can think of many practical situations in which mental ...
3
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4answers
888 views

Webapp password storage: Salting a hash vs multiple hashes?

For security's sake, of course it's blasphemous to store passwords in plain-text; using a hash function and then doing a re-hash and comparison is considered much better. But, if bad guys steal your ...
3
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1answer
154 views

Is a changing public truecrypt container secure?

I have a Truecrypt container which I want to synchronise between computers (i.e. different people, that I want to share the data with). If I used Dropbox for synchronisation and someone downloaded ...
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3answers
2k views

SHA1 usage for passwords, alternatives and advantages?

My application can authenticate via openid and oauth (facebook, twitter, etc) and also with its own authentication system. I previously switched hashing from MD5 to SHA1 and during migration I had to ...
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3answers
1k views

Dictionary attack on pass-phrases on common algorithms

I don't yet perfectly understand the difference between brute-force and dictionary attack since this differentiates one attacking the key and another attacking password: apparently attacking passwords ...
3
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2answers
384 views

Are there public slow-but-strong algorithms out there that resist brute-force attacks better?

I'm reading that AES uses 4x4 bytes (4*4*8 = 256 bits key) matrix for performances matters (since it's a requirement for common standard encryption algorithms), but are there implementations with ...
3
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3answers
537 views

Is public-key cryptography the only option in this scenario?

Two parties: a client and a server are to a agree on a symmetric key. Both the client and the server are aware of a master password. The way this is currently done ...
17
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3answers
9k views

How should I calculate the entropy of a password?

If part of the password is a whole regular English word, does the entropy of that part depend on the number of English words in existence, the number of English words known by the choosing algorithm, ...
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6answers
746 views

How can I improve a password generation scheme based on a shared secret and URL?

I currently use the following method to generate a different password on every website I have to login: password = SHA1 ( mainPassword . domainName . number ) ...
8
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2answers
763 views

How should I store passwords that need to be available in plain text?

Suppose I need to store login information for a third-party website for a few users, how would I go about doing it? Since I am logging into a third party website, I need the password in plain-text, ...
1
vote
1answer
553 views

iSeries (AS/400) Database File: password encryption

I am helping with a project in which an old software system on an iSeries is having a brand new .NET UI applied to it. It's going well... except... In order to allow users to login and maintain ...
10
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5answers
765 views

Why does PBKDF2 xor the iterations of the hash function together?

The definition of PBKDF2 states that I obtain a derived key* by calling a pseudorandom function a bunch of times recursively: ...
16
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3answers
1k views

Is using slow password hashing on the client side easier attackable than on the server side?

As we know, one should use a slow password hashing algorithm instead of a fast one for storing passwords, to hinder brute force attacks when the database is compromised. The problem with this is that ...
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2answers
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What makes a hash function good for password hashing?

Using a cryptographic hash to store e.g. passwords in a database is considered good practice (as opposed to storing them plaintext), but is subject to attacks on said cryptographic hash, assuming the ...