PBKDF2 is a key derivation and strengthening function, commonly used for password storage.
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Login system using authenticated encryption without storing user password
I'm not a security expert, so I might be asking a silly question, but let me describe what I am thinking about.
First, I know that a lot of web sites store hashed/encrypted passwords which could be ...
2
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3answers
57 views
User specified iteration count
I'm working on a PHP authentication and registration system following the standard salt+password = 'auth hash' and using the plaintext/unencrypted username as the lookup field on the initial query. ...
4
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1answer
72 views
RSA vs PBKDF2 for password storage (theoretical)
I know this is not the right way to store passwords, but I'm asking this from a theoretical perspective:
Suppose a web site's passwords were encrypted with RSA asymmetric encryption and the private ...
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2answers
194 views
Why is 8ms a goal for hashing?
I'm currently developing a small project in PHP, and as it involves user authentication, I've been researching what options I've got regarding hashing. I've settled on PBKDF2 primarily due to it's ...
6
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3answers
233 views
Increase the security of an already stored password hash
Right now we're using 1024 byte PBKDF2 with 256 byte user-specific salt and variable iterations. However, I would much prefer to be able to, perhaps once every year or two, to be able to flat out ...
2
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1answer
163 views
Improving Digest Authentication using PBKDF2
For a variety of reasons, I need to use digest authentication for a REST server that I have created.
I have come up with an "improvement" that I believe strengthens the algorithm against MD5 attacks ...
2
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3answers
210 views
Client-Side Hashing to decrease value of password guessing heuristics
Yes, this is 'yet another client-side hashing' question. But, don't leave yet, I think there is some value here.
I'd like to do something to mitigate the affect on the community as a whole when my ...
4
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2answers
227 views
How less secure is an encryption if we know something about the original data?
I have a number of files encrypted with a key derived from a password. In line with standard practice, I use a random salt and password and do many PBKDF2 iterations to obtain an encryption key and ...
3
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2answers
209 views
LastPass One Time Recovery Passwords--How?
The LastPass password manager stores One Time Recovery Passwords locally in each browser you use the plugin with:
http://helpdesk.lastpass.com/account-recovery/
My question is, how can you have more ...
3
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1answer
128 views
Key length and hash function in PBKDF2
On this page:
http://www.ruby-doc.org/stdlib-2.0/libdoc/openssl/rdoc/OpenSSL/PKCS5.html
they make a statement that strikes me as rather weird:
Key Length
Specifies the length in bytes of ...
3
votes
4answers
201 views
Is it safe to have the salt equal to IV?
If I'm using AES-256 CBC to encrypt, getting the 32 byte key using multiple iterations of the PBKDF2 function with a 16 byte salt, is it safe for me to let IV be equal to the salt?
(Edit: The salt is ...
3
votes
1answer
999 views
BCrypt+SHA256 vs PBKDF2-SHA256
From this question, the OP posited taking a user's entered password, running it through BCrypt, then running that through SHA256 to produce a 256-bit password-derived key. (EDIT: To clarify, these two ...
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3answers
119 views
Maintain sensitive key between requests
EDIT: Reworked question. Previous version too poorly asked.
On my website users write sensitive messages that must be kept secret.
The entire user area is over SSL, so the communication between user ...
5
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4answers
481 views
Gold Standard for password hashing
I've developing a web application that will be dealing with highly sensitive information and I want to ensure the hashing of passwords is gold standard. Ideally I'd go for per-user salted SHA512 ...
3
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6answers
293 views
Is there a table that compares hashing algorithms by speed, relatively (machine independent)
As far as I understood*, one of the major criteria when choosing a password / salt hashing algorithm is it's speed. To prevent brute force attacks, a slower algorithm is better (and also makes it more ...
2
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1answer
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Is there a better way to take advantage of current 'approved', 'proven', and memory/cpu-expensive algorithms while using salts and peppers?
I've read about the concepts presented in these two questions:
Pre-hash password before applying bcrypt to avoid restricting password length
Would it make sense to use Bcrypt and PBKDF2 together?
I ...
6
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6answers
753 views
Client side password hashing
Edit: Updated to put more emphasis on the goal - peace of mind for the user, and not beefing up the security.
After reading through a few discussions here about client side hashing of passwords, I'm ...
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5answers
275 views
What about combining pkdf2 with scrypt? [duplicate]
Possible Duplicate:
Would it make sense to use Bcrypt and PBKDF2 together?
How does the following password hashing scheme look to you?
iterations1 = scrypt iterations required to spend ...
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0answers
70 views
Recomended hash algorithm [duplicate]
Possible Duplicate:
How to securely hash passwords?
Do any security experts recommend bcrypt for password storage?
What would you choose between:
PBKDF2 SHA256 (270,000 iterations)
...
2
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1answer
1k views
Is PBKDF2 only SHA1 in C#?
I can't find a way of specifying the hashing algorithm used by the PBKDF2 (the Rfc2898DeriveBytes class) implementation in C# System.Security.Cryptography.
It seems to be just SHA1. Am I missing ...
7
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2answers
805 views
With PBKDF2, what is an optimal Hash size in bytes? What about the size of the salt?
When creating a hash with PBKDF2, it allows the developer to choose the size of the hash. Is longer always better? Also, what about the size of the random salt? Should that be the same size as the ...
4
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3answers
373 views
Trying to understand password hashing
I am trying to get a grasp of password hashing. Back in the days it seemed so simple, just MD5(password + salt) and you are done. Then md5 was proven to have collisions so people started moving to ...
7
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4answers
988 views
Challenging challenge: client-side password hashing and server-side password verification
We have a website where users need to log in to access privileged information. Obviously we are using SSL, but I also want to avoid plaintext passwords from accidently ending up in server logs, or ...
5
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3answers
361 views
Verify Login and Encrypt with PBKDF2
I'm writing a desktop application where I'm using PBKDF2 to generate an encryption key to AES-128 encrypt the config file. The config file contains a crypo-random key that's been used to encrypt the ...
4
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3answers
2k 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 ...
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2answers
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Can a biometric device serve as a user based entropy source?
I am wondering if a biometric device can be used to generate some entropy or key material that would be stable across each authentication.
The contrary would be for biometric devices to act like an ...
4
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3answers
311 views
How should I choose a difficulty factor for my password hashing function?
Assuming that I'm doing password hashing properly and using bcrypt, scrypt or PBKDF2, how should I go about choosing an appropriate difficulty factor? i.e rounds for bcrypt, iterations for PBKDF2 and ...
18
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5answers
765 views
Is it possible to increase the cost of BCrypt or PBKDF2 when its already calculated and without the original password?
I just wanted to know if you can increase the cost (iterations) of those two algorithms off-line.
I want to increase the cost every year of my users passwords.
One solution is to recalculate them ...
5
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1answer
1k views
Does NIST really recommend PBKDF2 for password hashing?
We hesitated between BCrypt and PBKDF2 for password hashing. In many forums and blogs people say something like "In their Special Publication SP 800-132 NIST basically recommends using PBKDF2 for ...
2
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3answers
652 views
Can the salt for PBKDF2 be a hash of the user-entered password?
I want to derive a key from a password in a client application that will be used as a master key that decrypts a data key. As far as I understand the salt should be private knowledge. Would it be ...
7
votes
1answer
657 views
Would it make sense to use Bcrypt and PBKDF2 together?
I've read various opinions about whether Bcrypt or PDBKF2 is a better key derivation hashing method. The answer seems to depend on a lot of complicated factors that are not easy to analyze. Would ...
20
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1answer
2k views
Are there more modern password hashing methods than bcrypt and scrypt?
This question made me start thinking about password hashing again. I currently use bcrypt (specifically py-bcrypt). I've heard a lot about PBKDF2, and scrypt.
What I'm wondering is if there are any ...
35
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4answers
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Recommended # of iterations when using PKBDF2-SHA256?
I'm curious if anyone has any advice or points of reference when it comes to determining how many iterations is 'good enough' when using PBKDF2 (specifically with SHA-256). Certainly, 'good enough' is ...
