Questions tagged [passwords]

Passwords are secret keys which human beings can memorize.

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1answer
227 views

aWallet Password Manager

After reading a lot of articles on ramping up the security of my web accounts, I started using aWallet Password Manager for Android to backup my passwords. I like ...
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1answer
181 views

Safety of having many passwords hashed with the same salt?

I'm working on a web application where passwords must be hashed on the client before it can be send to the server. This is because the user's raw password is used for cryptography purposes and can't ...
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1answer
1k views

How long will brute force of salted SHA-512 hash will take, if salt is known and possible characters in password are known?

Suppose I know that the password is composed of characters [A-Za-z0-9], length is unknown, but maybe less than 8. If I have information about the salt use to perform hashing, and also hashing ...
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1answer
38 views

Expanding truly random key into printable password for successive hashing

The STUN network protocol defines its client authorization in the terms of message-integrity check employing the following scheme [RFC5389, section 10.2]: $$ \DeclareMathOperator{\HMAC}{HMAC} \...
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2answers
138 views

Salt passwords with the username?

Salts should be unique so that an attacker can't brute force multiple passwords at once. However, since usernames are unique, wouldn't it be possible to use some representation of the username as a ...
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1answer
146 views

SCRAM Iteration Count Attack

I'm not sure if this questions belongs here or in the Information Security Stack Exchange, but here goes... With SCRAM (RFC5802), is there anything that prevents an attacker masquerading as the ...
3
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1answer
191 views

Benefit of capitalization when using Diceware passphrases?

If I use a Diceware generated passphrase of any given length, will capitalizing the first word (or any word for that matter) effectively double the number of combinations that would have to be tried ...
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2answers
1k views

How do I calculate a password space if the password only has eight alphabetic characters (not case sensitive)

I read this wiki article and saw this formula for random password's information entropy. Also the wiki article mention that the symbol count for non case sensitive is 36. Is there a way I can ...
3
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4answers
257 views

How many bits of entropy are leaked for every derived password from a master?

Given a master password that has a lot of entropy (similar to Bitcoin HD wallet seed words, 130 bits of entropy or more) how many bits of entropy are lost per leaked generated password? Let's take an ...
2
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1answer
359 views

Diffie-Hellman based password challenge response scheme

A very commonly used (examples: HTTP digest auth/CHAP/Kerberos) authentication scheme is something that looks like: Setup. Client and server both know a password $p$. Authentication. Server sends ...
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1answer
89 views

For WinRar, how long should a password be to make up for a lack of complexity?

Assuming that the best alternative to complexity is length, how long do you recommend a password or phrase to be when using WinRar? Note that I'm aware that it's not always that simple, but I would ...
2
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1answer
965 views

Use sha3 for passwords hashing

Is use of sha3 justifiable? Is sha3 better than sha2 in (m)any aspects? P.S. I want to use hashing for passwords in a database
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2answers
686 views

HMACSHA1 vs HMACSHA2 (for PBKDF2)

I need to choose an HMAC function for PBKDF2. I'm using .net so I don't have the option to use SHA3. At first glance, and according to this answer by Thomas Pornin it seems like SHA512 would be best....
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1answer
321 views

Why is password recovery so slow for Whirlpool hash, when compared with others?

I'm just curious about why brute force takes so much longer on the Whirlpool hash than it does on the others, as you will see below: ...
2
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1answer
190 views

Does this PBKDF2-SHA1 payload hint at a cryptographic security issue?

Blockchain first 16 encrypted bytes, IV, and iter_count – all encoded in Base64: Yms6xqrzCfFsQadVZ5gQonMtnQAAAAAAAAAAAAAAAAAAAAAQJwAA69tYNg== Does it looks like “...
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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 ...
0
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1answer
693 views

What is best practise for salting and multiple-hashing of passwords?

I have been presented with some custom PHP code for salting passwords and applying multiple rounds of hashing. It looks reasonable, but I fear home-grown crypto. Is there an existing password ...
7
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1answer
415 views

Is it safe to store both the AES-related data and the PBKDF2-related data (except passwords) in one file?

Assume an "encrypted data package" file format which includes the following data PBKDF2 algorithm salt rounds keylen AES algorithm & mode IV ciphertext where the PBKDF2 salt and AES IV are ...
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1answer
2k views

How do you get the original salt after it's been hashed to the user's password in the database?

I'm researching how to do salt and hashing. I'll be using SHA256. Here is what I found: To Store a Password Generate a long random salt using a CSPRNG. Prepend the salt to the password ...
2
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1answer
86 views

Salt for non stored passwords

I read a lot about the concept of adding a salt to a password and understand that it protects against rainbow table etc. attacks. But this kind of attacks are based on getting access to the server ...
2
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1answer
88 views

Pepper and key derivation/stretching

I understand the pepper concept of adding but not storing a secret and iterating through the set of possible secret values for verifying. But is pepper also useful when it comes already to the use of ...
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2answers
313 views

Comparing different hashes to confirm they came from the same string

Is there any safe hashing algorithm that returns a different hash each time (like bcrypt) but has the possibility to compare 2 different hashes and determine that they were hashed from the same ...
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1answer
640 views

How difficult is it to crack sha256(sha256(pin)) with a 6 digit pin and no salt?

My friend forgot the password to his electrum wallet but knows that it's a 6 digit pin. I looked into it and from what I can find electrum uses the sha256(sha256(pin)) to generate the key used to ...
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4answers
10k views

Is there a practical way to crack an AES encryption password?

I heard that the fastest method to crack an AES-128 encryption, or and AES-256 encryption is by brute force, which can take billions of years. But I can't help thinking there's got to be a faster way. ...
0
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1answer
424 views

How does GRC password generator get 512 bit of secret data?

I'm trying to understand how GRC password generator can get 512 bit of secret data while encrypting 128-bit of data. The generator address is located here: https://www.grc.com/passwords.htm See the "...
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2answers
658 views

Security of non-standard use for AES-256-CTR?

I have a string secret that I would like to encrypt for storage in a Yubikey's second slot. These slots can be configured to store up to 38 characters that are later "typed" by the USB device acting ...
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1answer
42 views

How to test massives amount of links? [closed]

Ok, I have a wordlist of many many links (of the same site with a bit of difference in URL). I'm certain that the majority of then will return the same result, a error page. But one will return the "...
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1answer
856 views

How secure is RSA for authentication?

I'm building a web-based password manager system and would ideally not send sufficient information to the servers to decode the raw text passwords of users. The plan is to encrypt the raw text ...
0
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1answer
349 views

Any point to AES on password with hardcoded key?

I'm inheriting a project that stores a used password in a config file, which is generated by the user giving their password in plain text, and the project giving back a key generated through .NET's ...
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1answer
628 views

Would Hashing A Password In Sha512 Using JavaScript Be Secure?

I've created a competition for a few friends of mine that wanted to learn the basics of penetration testing. In said competition, there is one section in which there's a log file you need to check out ...
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2answers
147 views

KDF-based password manager

I want to make a password manager that from a single master password generates passwords for my services. For that I thought that HKDF suits my needs, as it is able to generate multiple keys from a ...
4
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3answers
3k views

Using 32 hexadecimal digits vs ASCII equivalent 16-character password

Assume I'm using a cryptographic algorithm to pseudo-randomly generate a string that is specified to be 16 characters long. The string will be used as a passphrase when encrypting a file. So, for ...
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1answer
645 views

Simple secret key encryption with PyNaCl [closed]

I am playing around with PyNaCl to get a bit into cryptography atm. Now I wrote two scripts to encrypt a file with a secret key and then decrypt it again using that key. The encryption part works ...
0
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1answer
111 views

Issues with Seeding Random Number Generator Using Password

I am looking into zero-knowledge proof-based security. I noticed that a server never needs to be sent the user's password to authenticate them - the password can be used to generate another value that ...
3
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2answers
1k views

About salted passwords

In most applications, all passwords are salted independently. In terms of security (e.g. attack complexity), what are the consequences of the following differents approaches: All passwords are salted ...
3
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1answer
122 views

Is there a term for “bootstrapping” encryption by storing an encrypted key?

Say you want to encrypt a large file, perhaps a backup of a database. Encrypting the file will naturally take some time, due to the amount of data. Now, if at any point you want to change the ...
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2answers
288 views

Passphrases, Dictionary attacks and 'bit shift'

How much better would a passphrase be if you swapped the first letters of each word with a shift to the left: "correct battery horse staple" becomes "borrect hattery sorse ctaple" This would be ...
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1answer
354 views

Can a Password be Derived from a AES key?

This thought randomly popped into my head and I have not been able to find a clear, defined answer for it. Given an AES key, lets say an AES-256 key which is derived from a user password, is there any ...
2
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1answer
803 views

Can pbkdf2 be used with a fixed salt to give a deterministic slow hash?

I need a password hashing function that is deterministic. Correlation attacks are not a concern. The same password must produce the same hash. I just want to protect the password against dictionary ...
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2answers
224 views

Can multiple hashing weaken the password?

Problem. I want a longer key out of password than my hashing function provide. Idea. I want to hash password multiple times rotating chars one position each time and use composite key. Question. ...
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1answer
595 views

How important is length and complexity of personal password for AES-256 encryption?

I want ask you how important is to have complicated personal password for AES-256 crypto? For example if I use these two "types" of passwords: pass123 ...
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3answers
206 views

Is there any benefit to *really* strong passwords?

Suppose you had these two passwords: ...
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1answer
1k views

How to decrypt a string given as part of a game/prank? [closed]

I have been given an obviously encoded string, that looks similar to this: ...
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1answer
141 views

Understanding Password Complexity

I’m trying to understand how a program checks for passwords and how fast it iterates through a loop. I think I understand how to calculate the minimum required strength for my password. Estimate ...
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2answers
122 views

Total password count, given length and pool size

First, if my password is exactly 8 characters long, derived from a pool of 95 characters, then is the total amount of passwords I can create simply $95^8$ ...
0
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1answer
928 views

Password protected Excel files

I need to send an Excel file to someone, normally I would use encrypted e-mail, however, this is not an option with this individual. What is the minimum length password I can apply to this file to get ...
0
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1answer
2k views

extract password hashed in scrypt using hash and salt [closed]

I have the hashed password and its salt. It is encrypted using SCRYPT by firebase. How can I extract the plain text password from these two? Or alternatively, how can I re-encrypt or convert them ...
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2answers
936 views

UNIX password scheme and encryption function

Recent versions of Unix store encrypted passwords in a file that is not publicly accessible. Such files are called shadow password files. In the UNIX password scheme, if only the operating system and ...
0
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1answer
293 views

PBEWithHmacSHA512AndAES_128 and AES Modes like GCM [closed]

I've asked this question on stackoverflow And I think one gentleman has already answered the first part of question a) In my code i am keeping IV and salt with ciphertext. I wanted to use ...
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1answer
109 views

New Passwording? [closed]

I just want to note before you continue reading--this does not specifically apply to hashes or the key to encrypted messages. However, I am initially thinking about password/key solving/remembering by ...