Questions tagged [pbkdf]
A PBKDF is a Password Based Key Derivation Function, which can be used to derive key data or derive a "password hash" from a salt and password.
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1answer
95 views
PBKDF security if all but one keys are exposed
I'm trying to understand the security of KDF but stuck with PBKDF case (case 3). Suppose, we have the following settings:
$KDF(SK,salt_1) \rightarrow k_1$
$KDF(SK,salt_2) \rightarrow k_2$
The ...
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1answer
37 views
Is clientside encryption to hide data from server safe when using SSL?
I want to clarify right off that bat that I am using the SSL/TLS protocol on top of this, so I am NOT trying to implement my own protocol to send data securely. I simply want the server to be unable ...
14
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2answers
2k views
Password hash that can be upgraded without plaintext password
Most password hashes have a cost parameter that indicates how long the algorithm should take. Is there an algorithm where you can increase that cost for a particular hash, without access to the ...
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2answers
77 views
Is there an advantage to “weak” hashing and stretching over strong hashing?
Is there any sort of practical advantage to using a stretching algorithm such as PBKDF2 on say SHA256 over a straight SHA512 hash?
If the purpose of key stretching is to increase the length and ...
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1answer
339 views
Key Derivation Function (KDF) Usage [closed]
Is it common to have a KDF implementation in order to safely store passwords?
Do IT-companies use KDF? Or do they usually rely on other algorithms?
If you have any practical example for the second ...
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1answer
385 views
HMAC vs PKDBF2 as the first step towards HKDF
I'm implementing an application that from a password has to derive two keys, one for authentication with the server, one for encryption. I'm using Java, with JCA and Bouncy Castle.
So far, to ...
3
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1answer
256 views
Is there a security risk associated with using a PBKDF for an AES encryption key and Sha256 for a hash using the same password text?
I am writing an encryption program using C#. My goal is to secure files even if the computer is stolen and somehow logged into.
Assumptions
The code used to write the program is visible to a ...
5
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1answer
829 views
Why does LastPass hash their passwords with PBKDF2 this way?
LastPass is a password manager that I am sure many of you are familiar with. I have been studying LastPass's source code a bit. From their FAQs and what I can gather from their source code, the way ...
5
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3answers
937 views
Derive a key from a password and another key?
I would like to encrypt some data using a password. I want to use a function like PBKDF2 to turn my password into a key. However, I would like to also require a keyfile, for added security. My data ...
2
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1answer
170 views
Is there any use for PBKDF with empty password?
As the name suggests, password based key derivation functions are used for deriving a cryptographic key from, well, a password.
Is there any use for PBKDFs with empty password? Does it give any ...
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3answers
128 views
Function to derive an integer from a given password
I need to get an int, derived by a given password, to feed it to a deterministic PRNG as a seed. The derived int should not give away any clues about the password.
How can I achieve this without ...
2
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1answer
2k views
Generating passwords using Password-Based Key Derivation Function
I was thinking of using different and independent password for different websites, but not storing them in some password manager so I don't need to backup the passwords. I thought I could use some ...
3
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1answer
199 views
Encrypt a small amount of data with a password derived from PBKDF2
I have a small amount of data (about 128 bits) to secured with a strong password.
I plan to run PBKDF2-SHA2-256 on the password and a 128 bit random salt to generate a 256 bit derived key. Then with ...
0
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1answer
510 views
PBKDF2 without salt on 16 digit password
How secure would be to use PBKDF2 without salt (or with the same salt for all) with a 16 digits passwords that are unique and randomly generated (there can't be two identical)?
Assuming an adversary ...
0
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1answer
206 views
PBKDF2 with the same salt for all IDs
I have a unique identifiers that I would like to keep secure and provide information about it through tokens. These tokens should be verifiable after using the same algorithm on other end system with ...
6
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2answers
268 views
Are there any high level memory-hard PBKDF constructions?
The PBKDF2 construction from PKCS #5 v2 has the convenient feature that it can be implemented using only standard interchangeable cryptographic primitives. Specifically, it only requires the ...
7
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2answers
5k views
What are KDF parameters in OpenSSL command-line utility for `enc`?
I refer to https://www.openssl.org/docs/manmaster/apps/enc.html and see that the only parameter for key derivation which I can set explicitly (not considering the obvious ...
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1answer
56 views
Encryption strength when using a PBKDF
Suppose:
$m$ is a positive integer.
$n=2 \times m$.
$H: \{0,1\}^{*} \rightarrow \{0,1\}^n$.
$p$ is a password.
$s$ is a salt.
$K=\{0,1\}^n$ is the derived key.
$PBKDF(p,s)$ derives a key from $p$ and ...
-1
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1answer
978 views
Need CryptDeriveKey AES implementation in C#
I am integrating with 3rd party software that uses AES 128 encryption. I know this is not ideal, but the choice of encryption is up to the 3rd party software. I am using C#.
My problem is in deriving ...
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vote
1answer
115 views
Cycling hashing in PBKDF's and their limitations in strength?
I hope this question isn't too similar to one that's already been asked. I also want to point out I know part the answer already, AFAIK: I just want some expert input on this.
Let's model a hash that ...
32
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1answer
20k views
Password hashing security of argon2 versus bcrypt/PBKDF2?
I wonder if it can be approximated how much of a security margin the new argon2 hash, winner of the password hashing competition, can give over bcrypt or PBKDF2, for an attacker using large GPU ...
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2answers
173 views
How to generate backup key for PBKD functions?
I would like to encrypt some files using AES, Ill derive key from password using some standard PBKD function and use that as AES encryption key.
My question is, if user forgets the main password, ...
3
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1answer
102 views
Software interface for KDF and PBKDF?
I'm working on an implementation of Krawczyk and Eronen HKDF from RFC 5869. From Krawczyk's original paper, he identifies four inputs to a KDF in Cryptographic Extraction and Key Derivation: The HKDF ...
5
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1answer
215 views
Is there a tangible benefit in keeping the number of PBKDF iterations secret and not storing them with the ciphertext?
Suppose I have a local file and it is encrypted with a symmetric key derived from a strong passphrase, unique salt and $x$ number of PBKDF (e.g. Scrypt) iterations. I am interested in keeping this ...
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0answers
57 views
Security of simple Skein PBKDF mentioned in the paper
From the Skein 1.3 paper section 4.8, Skein as a Password-Based Key Derivation Function (PBKDF), it mentions the following as a simple PBKDF (S = seed and P = password):
An even simpler PBKDF is to ...
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2answers
799 views
Replacing the PRF in PBKDF2 with Keccak
I am unable to find a reliable, tested library for a decent password based key derivation function e.g. Scrypt in the programming language I am using, but I have a reliable library for PBKDF2 (which ...
3
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1answer
350 views
How does ccrypt work?
On many Linux/GNU distributions CCrypt (ccrypt) by Peter Selinger is available as a command line utility to encrypt files. How does the protocol work and is it ...
8
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1answer
3k views
What is the algorithm behind PasswordDeriveBytes?
Microsoft has created an implementation of PBKDF1 in the PasswordDeriveBytes class. It can however generate more bytes than PBKDF1, which is limited to the number ...
7
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1answer
2k views
PBKDF vs HKDF for pretty long key
I'm developing a messenger application with encrypted chats.
In the first version of the app I've used PBKDF2 (10000 iterations, SHA1, random salt) to extend a short user password and generate keys ...
3
votes
2answers
154 views
Is this a plausible PBKDF?
Background:
Hello, I'm working on a hobby project in which I might want to implement a key derivation function within a somewhat resource limited embedded system. For standard crypto functions, I ...
2
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1answer
673 views
Is this key management scheme secure?
I'm designing a scheme for management of a small number of cryptographic keys (< 100 at any given time) and I had an idea: rather than storing all the keys, could I just store one master key and ...
