PBKDF2 is a key derivation and strengthening function, commonly used for password storage.

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How to determine the good number of PBKDF2 iterations according to technology evolution?

I'm using PBKDF2 to derivate passwords but I never know what can be considered as a "sufficient" value for the iteration count. Technology evolves very fast and I would also like to know how often ...
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806 views

Is it safe to publish something encrypted with a password if you make it insanely difficult to crack?

Let's say you have a very important private key that you don't want to lose. You think of posting it to http://pastebin.com/ but then relize that elimanates the point. So you think of encrypting with ...
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30 views

SQLCipher and PRAGMA key on iOS

I'm a bit confused as to how SQLCipher handles the PRAGMA key provided for encrypting the SQLite database For background: I'm looking at options for encrypting application data at rest. From the ...
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61 views

Secure WebApp authentication

I know there are many questions about hashing passwords on the client side out there, but none of them, which I found, address my use case. My app will be end-to-end-encrypted and it is not an option ...
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Isn't using pbkdf2 + scrypt + bcrypt best?

Since slower is better and key stretching is an awesome way to increase security over potentially low entropy passwords, doesn't it make sense to use all three? To be clear, this is about ...
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Incrementing Work-Factor of Hash Functions Over Time

For a long time hash functions have required a work-factor in order to keep the operation "slow" enough to protect individual passwords in the case of a database leak. Bcrypt and PBKDF2 being notable ...
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363 views

Am I weakening symmetric OpenPGP encryption by deploying a custom pre-derivation?

I often use GnuPG to encrypt files with a passphrase. I'm very paranoid, and afraid that the key derivation used by GnuPG isn't slow enough. For this reason, I've decided to do my own key derivation ...
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124 views

How secure is my software for file encryption with AES-256?

I'm working on a project to build software for file encryption with AES in Java, it's operation is quite simple, but I was wondering if it is really safe. The program prompts the user for a ...
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104 views

Password based Asymmetric Key generation

I am looking for a password based key derivation scheme that results in an asymmetric key pair. I have worked with PBKDF and its variants but could not come up with any way of generating a key pair. I ...
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60 views

Is this use of PBKDF2 for generating passwords secure?

Reading Security Engineering by Ross Anderson, chapter 2.4.7.1 Password Manglers got an idea that finally seems to solve the issue I have with the existing 'I need to remember a strong* password for ...
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3answers
175 views

Parameters for PBKDF2 for password hashing

I use PBKDF2 with SHA-256 to store hashes of passwords. I use the following parameters: number of iterations desired = 1024 length of the salt in bytes = 16 length of the derived key ...
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168 views

How to securely transfer password from a registration page to the database [duplicate]

What steps must be followed to send password securely from the user registration page (i.e. client side) to the server over a non encrypted channel (http) when the user registers for the first time ...
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72 views

What password based key derivation does PKCS #12 use?

I would like to make a note that I have read all of rfc 7292. I am trying to decrypt encrypted private key in a pkcs#12 pfx file. The private key is enveloped within pkcs#8 shrouded key bag. The ...
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How to know which output length to request from PBKDF2?

I feel like I'm asking a fairly obvious question here, but with it being so easy to make mistakes in this space, here goes. From wikipedia: DK = PBKDF2(PRF, Password, Salt, c, dkLen) dkLen ...
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2answers
233 views

Best reasonable way to store a secret safely

I'm working on a software that need to store and use secrets. These secrets can be for example: a password to connect to a database a client secret for an OAuth 2.0 client_credentials grant. I ...
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180 views

Login details security using salt and hash, and a login role in postgresql

I am coding up the security for a website in express.js and postgresql database. Now I have been reading about salting and hashing and I have the code set up with pdkdf2 using the crypto module, but ...
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74 views

PBKDF2 constants

I recently found this PBKDF2 code: <?php /* * Password Hashing With PBKDF2 (http://crackstation.net/hashing-security.htm). * Copyright (c) 2013, Taylor Hornby * All rights reserved. * * ...
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LastPass Key Derivation Security Question

I have done some research about password managers and of course stumbled upon LastPass. There are plenty of questions and answers about the security of LastPass, but as far as I am aware none of them ...
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If I obtained a username and the salted password pairs from a server, can I login?

I am studying Salted Challenge Response Authentication Mechanism (SCRAM). According to the description at https://tools.ietf.org/html/rfc5802#page-8 it seems that the Client does not have to know ...
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429 views

Major industry password leaks using salted HMAC but without eg PBKDF2, scrypt

I'm trying to convince higher-ups on a project to use an iterative strengthening function to secure password-storage for a new system. The current proposal would store something like an HMAC of a ...
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125 views

Full Disk Encryption with random keys

TrueCrypt encrypts and decrypts a disk with a password which is converted into a pseudo-random key with the PBKDF2 function. Other FDE programs use random keys that are stored on the disk. Where ...
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61 views

How to verify a password/key on subsequent key derivations

The first time a user logs in to our app, we derive an AES key from their password using PBKDF2. The AES key is kept in RAM only and used to encrypt and wrap other keys and data during the session. ...
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Why should I choose SHA (such as SHa-512), instead of bcrypt or PBKDF2, for FIPS-compliance?

Due to regulation, my company needs to be FIPS-compliant. I was looking at the current list of FIPS-approved cryptographical methods and I notice that neither bcrypt or PBKDF2 are in this list. ...
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45 views

Is there any problem using empty salts with PBDKF for this purpose?

The aim is to generate a secure key for symmetric encryption. I have a master password, from which I want to generate the key for symmetric encryption, in order to encrypt other passwords. The idea ...
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322 views

Storing Social Security Numbers in a Database

I'm developing an online application that needs the user's social security number. The application won't be processed on the web server so I'll be using an asymmetric key. So a compromised web server ...
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Guessing the whole PBDKF2 output from 1 half

If I use PBDKF2 with a good enough password and salt to generate a 2n bytes key, does knowing the first or last n bytes make it any easier for a 3rd party to guess the other half of my key than using ...
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208 views

How safe is password based key derivation in the case of long password?

I am encrypting files inside a device and store it. So I need to maintain the same key throughout the life cycle of the device. For key derivation I use EVP_bytestokey() of OpenSSL. The problem in ...
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177 views

Clarification about IV in PBKDF2 to generate encryption key

I've realized that the following implementation isn't truly safe: $pb = pbkdf2('sha256', $_POST['pass'], "enc_salt", 100, 100); $d = openssl_decrypt ($data['container'],'aes-192-cbc', $pb, true, ...
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Protect against malicious client with key derivation function (PBKDF2)?

Consider a protocol that allows clients to retrieve XML "forms" from a server. Forms are identified by a unique, randomly generated form ID that is embedded in the form. Clients fill out the form and ...
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ECIES-like scheme using PBKF2?

I would like to marry ECIES to a scheme based on PBKFD2. Effectively, I want the Key Encapsulation Mechanism to use Diffie-Hellman, but rather than encrypting the seed material with the recipient's ...
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296 views

Do I REALLY need to change my LastPass password?

Last weekend LastPass' network was compromised and that a list of email addresses along with the hashes of the master passwords were stolen. It is being recommended that LastPass users change their ...
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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 ...
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Which KDF should be used for ECIES?

According to Wikipedia, ECIES requires a key derivation function. I already have an implementation of PBKDF2-HMAC-SHA256 in my library, so I could use this. Is PBKDF2-HMAC-SHA256 (salted of course) ...
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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 ...
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861 views

Tracking IP address to prevent abuse without logging user metadata

I am trying to balance good security practices against excessive logging of user metadata / Personally Identifiable Information. I am constructing a web app that allows for secure messaging. In part ...
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MD5 before PBKDF2 on legacy software

I am mantaining a legacy software that uses MD5 in the following way: The client asks for a 16 byte salt when authenticating an account. The server generates a 16 byte salt, links it to the account ...
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Sanity check security scheme, is it secure? Is there cruft?

This article: Life in a post-database world: using crypto to avoid DB writes Prompted me to write this url-crypt Node.js module to convert a Secret into secure urlsafe base64 strings. Think of an ...
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216 views

Combining SCRYPT + a short crc

I'm considering using SCRYPT for password storage. (I'm open to PBKDF2 as well, or bcrypt by itself). The issue is that I don't want this to become a potential point for a DDOS attack, given the ...
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181 views

Encrypting files securely using user supplied password

I'm currently trying to build a (sort of) secure, desktop based RTF text editor written for node-webkit using node.js. Based on some answers that I read here, such as How can I securely convert a ...
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Looking for a way to encrypt/decrypt data using a generated key that works in Windows and Linux

I am looking for a way to encrypt/decrypt data on windows and linux platforms. The data gets encrypted in windows and the same data needs to be decrypted on linux/windows and vice versa. I understand ...
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PBKDF2 strong salt

I want to use a strong authentication scheme, so I decided to use PBKDF2. I'm using PBKDF2 with SHA256 algorithm, 5000 iterations and I use username (which is full email address of user) as salt. So ...
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PBKDF2: can the salt be known from the hash?

I understand that some KDFs bundle the salt with the output, such as bcrypt (modular crypt format). In PKCS5_PBKDF2_HMAC (specifically, looking at OpenSSL implementation) with a single iteration, is ...
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Password history with PBKDF2

Scenario: Cannot use previous 15 passwords Using PBKDF2 with iterations targeting 1 second execution time In this scenario, when a user wishes to create a new password, the server must combine ...
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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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3answers
598 views

PBKDF2 used to generate an encryption key: long shared secret (password) vs iterations count

I want to use pbkdf2 to generate a key for a symetric encryption (DES, 3DES, may be AES) algorith, that will be used to secure private data between an AS/400 and another computer (probably running ...
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What is the right way to implement Keyed Password Hashing?

As mentioned in this wonderful link, the way to get a PBKDF2 Hash of a user given password given a password (of course), a salt (generated Cryptographically Secure Random Number Generator. iteration ...
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Simple PBKDF2 vs. scrypt question

scrypt was designed to use more memory. We can use its parameters to specify (approximately) how much memory we want it to require. But both scrypt and PBKDF2 allow us to specify the output data ...
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234 views

How to safely use a Key Derivation Function to secure private data - need guidance

I have some secure data created in my client app which I wish to store on the server as backup for the user. The user already has a password to authenticate with the server. The password is never ...
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190 views

Encryption and HMAC with the same password

I need to send authenticated ciphered messages by using a single password. Reusing the same (derived) key for the block cipher and the HMAC is not a good practice, I know. My initial idea is to ...
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538 views

Database row level encryption scheme

I am wanting to secure some highly sensitive data in a database. This would mean that the data needs to be encrypted and remain secure for 100 years if it were to fall into adversary hands. I also ...