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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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 ...
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2answers
211 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 ...
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1answer
180 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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8answers
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Does truncating the cryptographic hash make it impossible to crack?

I store password hashes in their full value for example, $h = sha256('foo') outputs 64 characters: 2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae I store that directly in the ...
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2answers
527 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 ...
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1answer
339 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When the subject of password hashing comes up, a lot of developers get exasperated by people using outdated, broken, or hand-rolled hashing schemes, and I frequently hear "just use bcrypt!"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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1answer
594 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 ...
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2answers
242 views

How does my bank knows my second and forth chars of my password [duplicate]

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 ...
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4answers
5k 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 ...
6
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3answers
581 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 ...
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3answers
2k 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 . ...
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1answer
326 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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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 ...
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3answers
165 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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1answer
212 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 = ...
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8answers
23k views

Why do people still use/recommend MD5 if it is cracked since 1996?

It's still commonly recommended way of hashing passwords, even if it's insecurity had been proven in 1996 Therefore we suggest that in the future MD5 should no longer be implemented in ...
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1answer
238 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?
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1answer
709 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 ...
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1answer
698 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 ...
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1answer
111 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 ...
2
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1answer
125 views

Is it possible to hash bcrypt passwords more securely?

I'm wondering if it's possible to increase the work factor of an already encrypted bcrypt password. e.g. I have a password that was encrypted with a work factor of 5, is it possible to increase the ...
0
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1answer
74 views

Is encryption less resistant to brute-forcing compared to hashing?

I understand that a hashing algorithm like bcrypt uses several rounds of hashing to make it computationally expensive for a brute-force attack. How does encryption work against a brute-force attack? I ...
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0answers
65 views

How do I determine whether a Linux-based router still has the default password? [duplicate]

My goal is to check if the password used by admin is the default password. I work on a Linux-based router. I know the password is stored as a hashed value in /etc/passwd. In generic Linux machines, ...
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1answer
1k views

Hash the signing key of an authentication token in database

I have clients which are all browsers. All clients render just a single page application getting data from a Web API. The design of the API follows REST principles. I use token-based authentication ...
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1answer
250 views

Is my hashing technique secure? [duplicate]

I am not sure if this is the best place to post this type of question. I have come up with function which, I believe, is a very secure method of hashing. (I could be completely wrong). Here's the ...
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2answers
234 views

Any reason to use bcrypt, pbkdf2, scrpt for other things than passwords? [closed]

Let's say I want to hash some data, using SHA256, in order to prove I know something. Maybe it's my secret ID for something. In the real of passwords we have moved from hashing -> hashing+salt -> cpu ...
6
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3answers
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Does checking the fingerprint of a self signed certificate improve security?

I am currently developing a component for an application that does TCP communication with a device inside a local area network. I use TLS to provide data encryption, integration and authorisation. ...
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1answer
4k views

About password_hash() in PHP and storing (part of) its salt outside DB

So, i learned that new in PHP 5.5 is password-hash() which works much like crypt(). Which is more secure (slower) than md5() or sha1(). The result string is algo+hash+salt, which can be passed as-is ...
3
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2answers
293 views

Hashes of overlapping data - does it make them easier to crack even when neither is cracked

Say I have strings: stringA, StringB, stringC. And I make two hashes: HashA = sha256(stringA + stringB) HashB = sha256(stringB + stringC) For the sake of the argument I'm suggesting sha256 but ...
9
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1answer
6k views

New to security, is php password_hash() good enough?

This is the first time I've had to handle personnel information and I want to make sure I have a good amount of security. I will be storing users' emails and passwords for their accounts on a MySQL ...
12
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1answer
302 views

Securing a prediction about a future event

I want to make a prediction about a future event, but only reveal that prediction after the event occurs lest knowledge of my prediction affect the outcome. For example, suppose Alice predicts that ...
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2answers
823 views

On what layer should password hashing and/or encryption take place

I'm finding myself on the inexperienced end of a discussion about where password hashing takes place. My coworker drew a schema from less to more secure, where the Public Internet was the least ...
5
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1answer
2k views

Best practice for data security on a web application

I read a couple articles on privacy/security but still cannot get a clear picture of the best practice to ensure that an attacker will not be able to access users' private information. For storing ...
2
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2answers
229 views

Keyed-hashing a password with a hash of the password + salt as the key, is it safe?

I was looking at our authentication system which hashes passwords differently than I was taught. The salt is a constant byte array and it uses the password + the salt as a key for the password hashing ...
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1answer
1k views

Is a simple Whirlpool hash with random salt secure enough? [duplicate]

I've been working on a site that requires users to login. It's written in PHP with MySQL, and passwords are stored as Whirlpool hashes with a salt (source code later). However, security sites or ...
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2answers
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Should I decode a base64 password before hashing for storage?

My server gets base64 encoded passwords from the client, and I am going to hash them for storage in a credentials table. Should I decode the password and hash the clear text password, or just hash ...
1
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2answers
258 views

Hashed Database: Hash Functions

Let's assume there is a database containing names and each name is hashed and the clear-text is deleted. If an attacker were to steal this database, would he/she be able to get the list of names?
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1answer
2k views

How many possibilities can today's computers check (per second) in a SHA512 hash of a 50-byte-long random entry? [closed]

The problem I want to avoid is "brute force" attacks against a database. So if I add a 50-byte-long cryptographically random salt to my information (which I don't need to retrieve, just its hash) - is ...
0
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1answer
310 views

Windows 7 password recovery [duplicate]

A few weeks ago I've changed the password on my old laptop, I forgot the password as I wasn't using it often. Now I need to recover the password because I used it to encrypt some important documents. ...
0
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2answers
184 views

Password stretching using concatenation of hashes

I'm working on a simple file encryption tool. Basically, here's how my program works: password = get_user_typed_password() salt = uuid4() key = bcrypt(password + salt) cipher = AES(key) for block ...
2
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2answers
362 views

Does sending two different hashes of the same password reduce security?

I'm updating a login system. The password is sent to the server as SHA512(password + long_string). I want to switch this to something like SHA512(username + password) in the future. By doing that I ...
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2answers
349 views

Is AES feasible for secure hashing files? [closed]

There was already a similar topic "Why AES is not used for secure hashing, instead of SHA-x?", but it was not about files specifically, and I, personally, am not convinced by the answers in it. "AES ...
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1answer
156 views

Sending Salts For Key Generation

I am working on a project that uses a combination of a web based framework (Django) and an installed app (Python) for the purpose of data entry/upload. I will have to send medical records over the web ...
3
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5answers
597 views

PCI-DSS and salt storage

PCI-DSS states the following: 3.5 Protect any keys used to secure cardholder data against disclosure and misuse I have a service which stores a salted bcrypt hash of the user's PAN. Assuming the ...
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3answers
327 views

Hash algorithm without ASIC's

I want to design a new crypto-currency, with an algorithm which is different from SHA-256 or Scrypt. But in order to do this, I need to know the hash algorithm which is the hardest to make ...
1
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1answer
73 views

Am I right by changing the default algorithm on a web app?

Numerous clients have told me that my suggestion on changing the algorithm on a web app does not increase security. I've tried reasoning that if the files have not been exposed, the attacker has to ...
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2answers
2k views

What is the advantage of using a symmetric cipher like AES to generate a keystream?

I see examples of AES (with a shared secret key) being used to encrypt shared secrets (e.g. nonce + counter) to produce a keystream against which the plaintext is XOR'ed to produce the ciphertext. ...
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1answer
150 views

Using multiple hash-functions along the line [duplicate]

I was wondering what the effect on strength/security is If I would use an aggregate of multiple hash-functions. For instance, I don't want to sent passwords in plain text (although it's over an ...
4
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2answers
2k views

How does processor architecture affect password hashing speed?

Does hashing speed vary significantly using different architectures (x86 vs ARM)? Scenario I am investigating the possibility of using a cluster of Raspberry Pi for cracking passwords hashed with ...