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.

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Cryptosytem Question [closed]

A file is encrypted and placed on a secure FTP server. An MD5 hash is taken of the file and also placed on the FTP server. A userlogs in to the server and downloads both files, however, the hash fails ...
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1answer
67 views

Cryptographic Hash function [closed]

How can I implement a cryptographic hash function using the block cipher? I was wondering whether I can use AES in cipher block chaining mode to achieve this.
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1answer
49 views

Is there an anti virus that protects processes from being injected code to?

As title says, is there an av that does that? And if not, is there any other program that protects processes like lsass in windows, apart from protected process utility in win8.1?
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2answers
276 views

Hash function with configurable length

Here's a short question: does a hash function with configurable length exist? And if not, why not? Would it be a problem?
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1answer
44 views

How many possible symbols and punctuations in a password? [closed]

I want to compute the possible combinations of a password consists of 8 digits of: alphabetical letters (26), numbers (0-9), symbols and punctuations. In order to compute this, I have to know the ...
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1answer
129 views

Is using MD5 in NTLMv2 protocol to store Windows passwords is secure?

I read that Windows (probably not new OSs but say, Windows Server 2008) stores passwords using Hashes using NTLMv2 protocol which uses MD5 hash function. My questions: MD5 is known to be insecure ...
1
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1answer
233 views

Hashing the cookie token for persistent login

In a login system I'm doing, I'm using a per-user, per-device randomly generated cookie token. A part of the script looks like this: // Generate current device's token $token = ...
1
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1answer
107 views

How does an attacker authenticate to a service using just the hash of the user (after performing a pth attack)

Let's say the attacker got the username and the password's hash. How can he use it when authenticating to some service in its domain with NTLM , for example? How can he send the request as the ...
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0answers
47 views

Does whosthere.exe of pth toolkit have to run with administrative rights?

To see the users that are connected to the machine and they're pass hashes with Whosthere.exe, do I have to run it as an administrator?
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1answer
47 views

How does LM hash deal with passwords that are between 8 and 13 chars

If its 14 then it splits it to 7&7, but how about 13 characters? 7&6? How does it work?
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3answers
55 views

Hashing algorithms [closed]

How can you tell which hashing algorithm is being used on a system? We are using 2048 bit encryption and wondering how to tell if hashing algorithm SHA-1 with SHA-2 is being used.
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4answers
279 views

How does a system authenticate a user using a hash function, after it has been salted?

I don't really understand how salting works. I read the Wikipedia article, but I still don't understand how can a system authenticate a salted hash? Let's say a user chooses a password. It's randomly ...
3
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4answers
326 views

True?: “Nearly all encrypted passwords are stored with the last character in clear text”?

[S]ome passwords are gleaned by hacking into computers where intruders can find stored passwords. Those are stored in encrypted form, but there's software that can attack the encryption. Nearly ...
3
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4answers
271 views

When and where do I hash a password?

Say I have a client and a server. I want the user with the client to login to the server with a username and password combination. To login, they have to enter the right password which (when hashed) ...
0
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1answer
75 views

What kind of encoding/hash it is [closed]

I have email which is stored in Cookie : %2FGl%F8%7E%06%F1S%FEF%10%E0T%B3%95%82BK%D9%D3%94%BC%AE%E1 which is sth like this after convert it with this tool : ...
1
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1answer
146 views

FIPS 140-2 C# Password Hash

Is the following algorithm, using RNGCryptoServiceProvider & Rfc2898DeriveBytes, sufficient to implement a FIPS 140-2 password hash on Windows Server 2008R2? var provider = new ...
3
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2answers
124 views

Why use PBKDF2 over multiple iterations of a another cryptographic hash function?

People often recommend PBKDF2 over using hash functions directly, but typically they compare PBKDF2 to a single unsalted hash. What advatages are there to using PBKDF2 over multiple iterations of a ...
15
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1answer
1k views

Why does Facebook bother comparing old and new passwords?

An answer to this question says Facebook generates a bunch of password guesses to see if they hash the same as a previous version of the password. Why bother? If a service forces every password to ...
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1answer
49 views

Verify external data files for an application

I have a C++ application with an algorithm, whose usage I want to protect. The application needs several input data files to work (those may change for each client). My goal is to allow only ...
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1answer
89 views

Review of approach to client-side only hashing and encryption for web application

Background: I have little knowledge of hashing and encryption, so please bear with me. I have posted a related question here: ...
2
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4answers
330 views

Why is client-side hashing of a password so uncommon?

There are very few websites that hash the users password before submitting it to the server. Javascript doesnt even have support for SHA or other algorithms. But I can think of quite a few advantages, ...
114
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5answers
11k views

Does Facebook store plain-text passwords?

I was about to reset my Facebook password and got this error: Your new password is too similar to your current password. Please try another password. I assumed that Facebook stores only password ...
1
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0answers
87 views

Persistent login by hashing password hash

It seems that persistent logins are technically the same as storing a password on the client, and therefore should be avoided whenever possible. However, real life users would be unhappy with having ...
1
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3answers
194 views

Is a file hash checking system 100% secure and non-bypassable/fakable?

I'm building an open source distributed (and partly offline replicated, as it's assumed that the network will be unstable) CMS and one of the core system 'job' will be to group all the files and ...
1
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2answers
95 views

Using “Dynamic Hash Technique” to protect cookies from XSS?

This paper appears to describe a solution in which XSS attacks stealing cookies are made pointless by having the server send clients a cookie with a hashed name. Whenever the user sends the cookie ...
2
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1answer
81 views

What to do with the extra bytes in ECDHE-RSA-AES-GCM-SHA?

I'm trying to implement, as an exercise, a protocol based on the cipher suite ECDHE-RSA-AES256-GCM-SHA384. As I understand things, ECDHE is used for the key exchange, RSA for the authenticity of the ...
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1answer
94 views

Is bcrypt suitable for modern use? [duplicate]

When the subject of password hashing comes up, a lot of developers get exasperated by people using outdated, broken, or hand-rolled hashing schemes, and I frequently hear "just use bcrypt!" repeated ...
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2answers
450 views

Is my hashing method secure? [duplicate]

I use bcrypt (32 rounds) and once the hash is produced, I get the sha512 of that hash and I then hash that with blow fish and once that is done, I hash it again with sha512 with a salt that has been ...
1
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1answer
124 views

Hash Security of Windows 7 Password

I need to find some materials about how Security Accounts Manager(SAM) works in windows 7+. I am confused with the storage format of hashed value. Many materials (such as, 1) tells me that it uses ...
3
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2answers
159 views

How does my bank knows my second and forth chars of my password

I see that the new login mechanism used by some banks in UK and also used by visa debit authentication is to ask for three random characters from your password at login (for example second, ninth and ...
17
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4answers
3k views

How secure is Java's hashCode()?

On our views in a Java web application, currently I am using hashCode as Id's for objects so that at server end I can get the same object back. However, I am wondering how secure Java's hashCode ...
5
votes
3answers
512 views

Does it make any sense to alter a hashed password? [duplicate]

I've always wondered if it would make any sense to put fake characters into a hashed password? For example this is my password: 1234 and after hashing the password , this is the result: abcd Then ...
0
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1answer
78 views
2
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2answers
156 views

Locality Sensitive Hash (LSH) function to approximately match old passwords

Recently, I ran across a website that requires me to change my password after X number of days had passed since I had last created one. Intelligently, the service made sure that the password did not ...
2
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2answers
613 views

How weak is MD5 as a password hashing function ?

A professor told us today, that MD5 is weak. I understand his chain of thought but pointed out, that IMHO MD5 is a good way to go if you would use a long (even really long) dynamic salts and static ...
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2answers
191 views

How to treat/hash ECDH shared secret to use as keys for AES?

I'm doing some studies/development for a security system that would use ECDH with ephemeral keys. In my code I'm currently using a 256-bit EC, so when the two parts compute the shared secret, I get a ...
1
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2answers
332 views

How secure is the PwdHash algorithm and system?

I use the PwdHash service (http://crypto.stanford.edu/PwdHash/) and plugins for pretty much all of my passwords. I believe this is safer because: No service gets the same password as another, so if ...
2
votes
1answer
295 views

ASIC/FPGA hardwares to compute Scrypt hashes [closed]

this company claim Scrypt mining by ASIC (on crypto currencies who use scrypt hashing as proof of work) scrypt is made to keep ASIC/FPGA attackers away, is that claim expired?
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2answers
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How do you overcome the problem of the salt being public and known by the attacker? [duplicate]

I believe that when adding a salt to the password you need to store the values so you can compute the hash again. But, what does happen if the attacker get the salt? How is it possible to add value ...
0
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3answers
104 views

Using a Hash as a Salt? [duplicate]

Ive done a bit of reading on the subject of Hashes and Salts and I came up with an idea for a salting scheme but I wanted to check it with some people more learned than myself. My basic idea is to ...
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votes
1answer
53 views

login not working using hash_pbkdf2 [closed]

i am storing the password using hash_pbkdf2 but now ive hit on a problem my code : 1.for register $salt = openssl_random_pseudo_bytes(125);//salt $final_pass = ...
3
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1answer
101 views

A pair of 'self-signing' hashing functions?

Does a pair of (hashing) functions for which where neither g(x) nor f(x) are constants exists?
1
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2answers
247 views

Hash user id securely

In my app I'm using Facebook login and creating a local user in my DB after retrieving the data. When saving the Facebook ID in the DB I need to hash it, as I don't want the ID to be in clear text if ...
1
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3answers
366 views

What is the correct way to make a password salt?

I've made the below function to make a completely random 64 character long hash function password_salt($password){ $salt = hash("sha512", mt_rand(1,100000) . strtotime("now") . $password . ...
3
votes
1answer
130 views

Improving magnetic stripe card security with a “magnetic noise” hash?

I was reading the wiki on magnetic stripe cards when I stumbled across this sentence: "Magnetic stripe cloning can be detected by the implementation of magnetic card reader heads and firmware that can ...
121
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8answers
9k views

Why are salted hashes more secure?

I know there are many discussions on salted hashes, and I understand that the purpose is to make it impossible to build a rainbow table of all possible hashes (generally up to 7 characters). My ...
2
votes
1answer
174 views

Legality of downloading leaked hashes / attempt cracking [closed]

Note: I realize there is no legally binding talk hereinafter. There are lots of leaked password hashes on the internet. Twitter searches for "hash dump" pull back tons of links, generally from "deep ...
0
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1answer
133 views

Is it possible to insert data into UUID?

Is it possible to insert arbitrary data into UUID? Let's suppose we have an MD5\SHA hash of something... can we encode that data into a valid UUID?
1
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1answer
182 views

Retrieve RAR Password through Extracted File

So I was wondering about something, but for the simplicity, consider this example: You have a file with n encrypted files in it, of which one is called 'Note.txt' You also happen to have another ...
0
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1answer
58 views

Storing third party auth info; Is this secure?

I have a feature request to connect my PHP web-app to the users mail server. I have usually strayed away from this type of work as it will mean storing the users email passwords. My question: is it ...