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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1answer
297 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
80 views

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
108 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 ...
3
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1answer
134 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 ...
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1answer
56 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 = ...
0
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2answers
4k views

If hashing is one way, why can we decrypt MD5 hashes?

I have read some times that hashing is a one way function, that is you can make the hash of a message, but you can't recover the original message from the hash, just check its integrity. However, if ...
17
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8answers
11k 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 ...
34
votes
15answers
5k views

Why do people think that this is bad way to hash passwords?

Well, please tell me, what's wrong with this code: $password = "hello"; $password = md5($password); for($i=1;$i<20;$i++){ $password = md5($password); } It's exactly the same as this one: ...
0
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1answer
134 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?
2
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1answer
190 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 ...
1
vote
1answer
196 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 ...
0
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1answer
99 views

Breaking encryption with hash value of password?

Can you break an encrypted volume if you know the source code of the crypto-tool used and the hash value of the secret passphrase? Why is it not possible to just reverse engineer the passphrase ...
1
vote
1answer
77 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
votes
1answer
58 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 ...
7
votes
3answers
3k views

HMACSHA512 versus Rfc2898DeriveBytes for password hash

We are currently using HMACSHA512 in .net, with a 128Char (64byte) validation key The salt is 64 char randomly generated string. We allocated 2048 length on the database for the hashed base64 string ...
1
vote
0answers
58 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, ...
1
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3answers
1k views

inquiry about SHA1 with RSA for certificate signature

As you all know, plenty of X.509 Certificates use (PKCS#1 SHA1 with RSA encryption) as the Certificate Signature Algorithm for generating the signature of 2048 Bits long. We know that SHA1 hash ...
0
votes
1answer
424 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 ...
-1
votes
1answer
155 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 ...
0
votes
2answers
142 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 ...
5
votes
3answers
552 views

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. ...
0
votes
1answer
556 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
votes
2answers
160 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 ...
2
votes
1answer
623 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 ...
9
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1answer
188 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 ...
1
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2answers
178 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 ...
3
votes
1answer
565 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
votes
2answers
136 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 ...
1
vote
1answer
244 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 ...
1
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2answers
398 views

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
vote
2answers
183 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?
1
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1answer
1k 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
votes
1answer
153 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
votes
2answers
102 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
votes
2answers
167 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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votes
2answers
179 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 ...
1
vote
1answer
105 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
votes
5answers
371 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 ...
0
votes
3answers
160 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
vote
0answers
64 views

Login details security using salt n hash and a login role in postgresql

I am coding up the security for a website in express.js and postgresql db. Now I have been reading about salting and hashing and I have the code set up with pdkdf2 using the crypto module, but my ...
1
vote
1answer
68 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 ...
0
votes
2answers
629 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. ...
0
votes
1answer
72 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 ...
3
votes
2answers
282 views

How can I store a password history to prevent reuse?

I have an application with a user database. The database stores the password using a bcrypt hash with a randomized salt. How can I implement a password history set (to prevent password reuse) in a ...
4
votes
2answers
870 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 ...
5
votes
4answers
417 views

Is it a good idea to have a “master” password?

Though I do have a good memory of passwords, it is quite impossible to have one password per application. Yet, it should be... My current way to deal with passwords is to have five passwords and to ...
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0answers
24 views

How is password character validation in 3D secure is implemented? [duplicate]

We have a website which stores hashed passwords in the database. During logins we hash the password entered by user and compare two hashes. This is quite standard so far. Our client which is in ...
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votes
1answer
91 views

What is this encrypted with or where can I find examples of encryptions to compare it with? [closed]

I have a hash thingy I am trying to decode and I have done relatively little with encryption, though I would like to try to learn some more. The hash is: 1YMTpavsFq7ykllC3CCsg3e1li31re1nROxuW1wqIqpk ...
61
votes
2answers
10k views

What are rainbow tables and how are they used?

Where can I find one? Is there a pot of gold at the end? How do I protect against them? From the Area51 proposal This question was IT Security Question of the Week. Read the Sep 09, 2011 blog ...