A hash algorithm is a function which takes a variable size input and produces a fixed size output. The algorithm tries to make it difficult to predict the output for a given input, find two inputs with the same output, or reconstruct the input from the output.

learn more… | top users | synonyms (1)

13
votes
3answers
2k views

Is too long salt reducing security of stored password hash?

Suppose we have statistically 7-8 characters long passwords. Is appending a 200-characters long salt less secure than 5-characters salt, because of similiar hash function inputs? I was wondering, ...
5
votes
4answers
131 views

Are there any disadvantages to encrypting the password hash?

Is encrypting the password hash in database more secure than storing only the hash? Suppose we store encrypted SHA-256 result with AES instead of hash directly. Is this a good protection from a ...
1
vote
1answer
31 views

Using salt or secret for Hmac

I'm working on a web API. We are going to use Hmac256 for signature hashing. From what I can gather, the secret is a key used to initialize the hash algorithm (ie to generate a random number). The ...
-2
votes
0answers
29 views

Please help me to find the Hash algorithm and decrypt the password [on hold]

I want to decrypt a encrypted password 5a645f09c682eadf4c93359632b29589bae7051c I tried but I couldn't find the hash algorithm.Can you please help me?
-1
votes
0answers
31 views

Configuration file with 12-character XML-encoded passwords [on hold]

I have received a configuration file with 3 passwords I'm trying to crack. However, I'm having a hard time determining what hashing/encryption mechanisms are used for the passwords. The cipher ...
1
vote
1answer
78 views

How are SHA1 and MD5 considered to not protect against collisions?

SHA1 and MD5 hash functions are considered to not protect against collisions while SHA2 is. Is it the size of the message digest that makes this or the algorithm itself? If it is based on the message ...
1
vote
2answers
49 views

bscrypt,scrypt v/s iterative SHA-x [duplicate]

Both bcrypt and scrypt hashing algorithms are designed to increase the resources required during the computation. Hashing passwords with these algorithms can be beneficial as it makes the task of an ...
2
votes
1answer
22 views

Feeding PBKDF2 to SRP verifier creation

There is an older game that solely uses UDP to communicate, and I wanted to add password authentication to the game to facilitate things like experience points and rankings. To this end, I decided to ...
2
votes
3answers
87 views

Can password_verify() be used to identify password after database breach?

I am a newbie to PHP and password hashing. I am following the instructions provided here to hash my user password before storing. My questions are: PHP recommends password_hash() method as a ...
1
vote
2answers
72 views

Storing AES password for verification

I was wondering if such practice would be safe: I have a table that stores encrypted notes Every note has a data field and a password field When a password is entered, i want to select all notes, ...
1
vote
2answers
145 views

Stream/block cipher add a simple hash to guarantee integrity

The question is simple: Adding a hash to a message and then encrypt it using a stream cipher / block cipher. Why can't this guarantee integrity of the message upon decryption?
-8
votes
1answer
124 views

Someone help me decode this [closed]

What type of hash is this? a9df6dcd35f4e7223ff3dd087abcc266 I can't find anything when I decrypt it. Please someone decrypt it
2
votes
1answer
106 views

How Windows Server 2008 Stores Local Users Passwords?

It is not clear to me how Windows Srver 2008 R8 stores local account passwords. Is there any salt added or just NT hash is computed and stored. The following article describes all the methods used by ...
1
vote
0answers
11 views

Pros and cons between HOTP and TOTP [migrated]

I'm reading the RFC6238 (TOTP) and RFC4226 (HOTP) standards and can't get which one is to prefer? I've searched around a bit and it seems like TOTP is the one that is most used, but some argue that ...
27
votes
2answers
4k views

How bad is it to truncate a hash?

I'm wondering how bad it is to truncate a SHA1 and only compare, say, the first 10/12 bytes, etc. I'm working with a fixed length of 8 bytes that I need to hash for uniqueness but store with the ...
3
votes
2answers
111 views

Similarity comparisons with hashed passwords possible?

At a company I worked at, I had to change my password every 90 days and I could only reuse a password after 8 iterations. This no-reusal included passwords being too similar to the old one, e.g. when ...
1
vote
3answers
95 views

Site allows both Partial and Complete password authentication; do they have my password in plain text? [duplicate]

My bank provides online banking facility like most of the banks these days. On the web they have Partial Password Authentication. Although I don't really believe in PPA providing extra security but ...
1
vote
1answer
57 views

Multi hash security [duplicate]

Is md5(sha1(pass)) more secure than md5(pass)? For example in case of sqli when attacker cant get our hashing schema, brute force or dictionary attack would be much less efficient. Am i right or is it ...
-2
votes
2answers
63 views

Strength of WPA passwords

How long would it take to crack an 8 letter (latin alphabet, lowercase) password of a WPA PSK network? Is it in reach of a single PC running hashCat?
20
votes
6answers
2k views

Is it fundamentally possible to validate that an unmodified version of your client connects to your server?

I'm cross posting this question from Programmers.SE because I think it's equally on-topic here and would like to pose the question to this community as well. This seems like a programming question ...
2
votes
0answers
44 views

Are there any ways to leverage NTLM V2 hashes during a penetration test?

I am on a penetration test at the moment, where LM/NTMLv1 hashes are disabled. I have captured a number of NTLMv2 hashes via NBNS spoofing, however was unable to crack them after running them through ...
0
votes
2answers
98 views

Are there any good tools to test the encryption quality of data?

I am trying to increase my understanding of data encryption, and I was wondering this. It would be really nice if there were any good tools to test how secure my encrypted data is, for example how ...
3
votes
1answer
240 views

Perfectly Robust Hashing Scheme, or Completely Over-Engineered?

This is going to get long, so prepare. Basis of the question is, Do all these steps improve security, or am I completely overthinking the problem? Are my assumptions/thought process valid? We all ...
0
votes
2answers
52 views

What is the solution for handling exceptions in password hashing schemes?

There is a technique called password hashing that describes creating unique passwords based on a unique master key and a static and arbitrary hash value. Using this technique, the user only has to ...
-4
votes
1answer
85 views

How does https check md5, sha-1 and sha-2 fingerprints?

When a https site shows multiple finger prints, i.e.: md5 and sha1, or sha256 and sha1, how does the browser check? is it both just the "strongest" or whatever is convenient? This question arose ...
40
votes
8answers
6k views

Do bad passwords produce bad salted hashes?

When you have a password stored in a database that has been strongly hashed and salted does it really matter if the underlying user password is weak? If you setup features like limiting login ...
1
vote
2answers
54 views

XOR-Cascade of weak hash secure?

I have following theoretical question: Let H(X) be a hash function which is considered as weak because collissions can be produced (e.g. SHA1, MD5). I wonder if following functions: H2(X) = H(H(X)) ...
3
votes
1answer
80 views

How to best to secure data over HTTPS

My aim is to have an (iOS) app in which the user would login, then on sucsessful login, gain access to additional information over an encrypted webservice (undecided). From research, I understanding ...
8
votes
5answers
1k views

Should I remotely store my salt? [duplicate]

When users register on my site, I want to store their username and hashed password in my database. When I hash that password, I'm going to salt it using PHP. The issue is, I don't want to store the ...
0
votes
3answers
59 views

How SplashData knows about Worst Passwords used by users annually

It is known that every reputable website stores their user passwords into their database after implementing some hashing algorithm on it, and even they don't know what the actual password of the user ...
0
votes
1answer
103 views

Identify an unknown type of hash [closed]

I've come across an unknown type of hash value which looks like this: AAAAAATOM2KIII+kbR/Dqw3TLTw4PHsGPZft2c+b93rImFIuAQ== The corresponding hex string is: ...
1
vote
1answer
42 views

truncated hash for message authentication?

I am using hash for authenticating the signature of the message. since the hash will be part of a url that is used for QR code, I would like to keep the hash as short as possible in order to generate ...
-2
votes
1answer
91 views

What is “Pass the hash” attack?

The article on Wikipedia doesn't explain how the attacker can authenticate to the remote server using the hash instead of the original password. According to the following article the attack is still ...
3
votes
2answers
237 views

Is it unsafe to have hashes of parts of a private string

We have string B and the hashes hash(P+B), hash(P); is it possible for P to be revealed easier using this information than having hash(P) ? What is the difference ? Any links to articles or any ...
1
vote
2answers
117 views

Is it a good idea to use the user's username as a salt when hashing a password like hash(username_str + password_str)?

I'm helping my friend with hashing his passwords, and I've a question - Should he use one secret string as salt for hashing or is it better to have each user its own salt for hashing? Consider these ...
-2
votes
3answers
122 views

My friend hashes passwords with SHA512 algorithm without salt. How do I convince him that he needs to add salt?

Today I discovered something incredibly stupid - my friend hashes user passwords with sha512 algorithm without a salt. I immediately raised this issue to him but he said he wants to see anyone crack a ...
2
votes
2answers
89 views

Difference between Second Pre-image Resistance and Collision Resistance in Cryptographic Hash Functions

I am studying the subject from these notes. However it is not clear what is the difference between "Second Pre-image Resistance" and "Collision Resistance" properties of Cryptographic Hash Functions. ...
2
votes
1answer
62 views

Security of shared “super pin” code table at meineschufa.de

The german brank credit report service "Schufa" uses a so called "SuperPIN" to enable users to reset their password. This super pin is a permutation of 30 lower and upper case letters and digits and ...
1
vote
0answers
98 views

Breaking it gently

Let's say I've found a fundamental error with mathematics of a security package. For example, let's say I've found something similar to the Pollard’s \rho-1 algorithm that renders some of the RSA keys ...
3
votes
1answer
130 views

Windows system password hashed - see which hash is used

How can I know / see if my windows is using NTML, LM, NTML2 for its user account passwords? What is the standard today, in windows systems?
1
vote
1answer
66 views

Can a known MD5 hash limit the search space for SHA1 collisions?

For a course in game theory, we are dealing with BitTorrent and alternative strategies (roughly alternative clients) we can employ to maximize our download speed. One strategy is to over-report the ...
0
votes
0answers
237 views

John the Ripper - Calculating brute force time to crack password

I'm using incremental mode (brute force) mode in John the Ripper to crack Linux MD5 passwords. I'm trying to calculate the time it will take to run through all combinations of 12 passwords (with 12 ...
3
votes
3answers
487 views

Accepting other similar passwords when storing a salted, hashed password

If a website stores passwords as a salted hash, is it reasonable to accept similar passwords as correct? For example, given the password stackexchange, does it dramatically decrease security if the ...
5
votes
3answers
245 views

Calculating password hashes in the browser?

I just finally got into Keybase and was surprised to see this in the sign-up page: Shouldn't password stretching and hashing be done on the serverside, as we normally don't trust a client?
7
votes
2answers
415 views

Does Outlook store plain-text passwords?

A long time ago when Microsoft changed my e-Mail from Hotmail to Outlook the password-interface said that I should only put in the first 16 chars of my password. But my password was longer before. So ...
1
vote
1answer
95 views

Adding hash value to user supplied URL in a web application: any security benefit?

We administer a Java web application from an external supplier where we have access to the source code. The user is able to provide an external URL which is stored in a database and later on embedded ...
4
votes
0answers
96 views

Does password-hashing “busy-work” need to be cryptographically secure

All modern password hashing schemes are deliberately designed to include a huge amount of "busy-work", to limit the speed with which an attacker would be able to conduct password hashing attempts. ...
0
votes
1answer
101 views

How to decode/decrypt strings of text [closed]

So I'm trying to decrypt/decode some text strings. I don't believe they're hashes because they vary in length too much and the software they are used for is able to easily decode them and display them ...
0
votes
3answers
106 views

Is is necessary to encrypt the message digest?

In symmetric key settings, in order to provide the message integrity, we compute the hash of the message. The message along with the message digest is then encrypted. Is it necessary to encrypt the ...
10
votes
2answers
166 views

How safe are signed git tags? Only as safe as SHA-1 or somehow safer?

How safe are signed git tags? Especially because git uses SHA-1. There is contradictory information around. So if one verifies a git tag (git tag -v tagname), then checksouts the tag, and checks that ...