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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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, ...
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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?
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118 views

Difference between OS X md5 and gnu md5sum

I have installed the "md5sum" utility on my Mac and there was also a "md5" binary pre-installed in /sbin. My problem and question is this: "Isn't MD5 a standard algorithm?" Because I get different ...
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121 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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241 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 ...
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183 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 ...
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218 views

How can I generate a unique SALT for multiple apps sharing one user database?

Let's say that I have one Database, and several separate web applications that share the database. If hashes are to be unique and generated on the server-side, how can I ensure that I am generating a ...
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277 views

For what do I hash user passwords with PDKDF2 when the user data is stored in the same database?

I'm hashing the passwors of my users with PDKDF2 right now. A user can gain access to his account with his password. When the user is logged in he can edit his personal information and do other stuff ...
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232 views

Does this kind of hashing exist?

Let's say you have two user defined strings, X, Y and you want to hash them into the hash Z. That is what most websites would do, X is the user's password and Y is the salt. It takes a lot of time to ...
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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 ...
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Search on hashed data

We have a request to encrypt customer personal data (e-mail, address etc.) We use MySQL which does not have any TDE like MS SQL or Oracle. So along with encrypting data we need to preserve ...
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175 views

Hashing Email Address and Contacting User

I am thinking about a log-in web service that would store a users username, password, and (optional) email address. If they forget their username or password, they can have their username and a ...
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72 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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316 views

Brute Force In Order Or Random?

Which is faster, on average to find the original plain text of a hash: brute force in-order, or with random plaintexts?
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How secure is my private key in the Windows Digital Certificate store?

Many files we download don't have digital signatures. Files may get infected or someone may intentionally modify them on our hard disk. So I wrote a simple file hashing program in c# that creates a ...
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538 views

Password entropy match for alphanumeric but there are special characters in password

I have a problem cracking some of the fundamentals on passwords' entropies. Namely: I have read this article about a guy cracking DKIM of Google (maybe more noticing that the keys are only 512 bits) ...
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97 views

How to verify that a clientside-generated object is genuine?

I know that general best-practice states not to trust anything generated by the client. With that in mind, I want to write an HTML5 app that utilises the browser to generate various objects ...
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184 views

Stripping / appending characters from user password before hashing to conceal it forever?

I had this idea to permanently conceal user password by requiring minimum length then stripping certain characters. For example if the user password is secret123, the system will strip it down to ...
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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 ...
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82 views

Is there any way to log in with a hash?

I've understood that the following steps are taken when I log in to a site: 1. My password is hashed 2. The hash is compared to what's stored in the database. 3. If the hashes are equal, I can log in. ...
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266 views

Which hashing algorithm is ideal for use on the web? [duplicate]

I am new here, and have poked around the site looking for an overview of which hash algorithm to use on the web and why. It seems to be the consensus that SHA-256 or other SHA-2 family algorithms are ...
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602 views

Reversing a block hash of SHA-1 with known Plaintext?

Is it possible to reverse the hashing of a block in a Datastream fed to an SHA1 if the plaintext for that block is known? If it is not possible (which I assume) does it make attacks to retrieve the ...
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276 views

Could a user never store a password if a username/email hash was used instead?

So I was just thinking about token_authenticatable setup from devise (rails gem), and this thought occurred to me: Could we strengthen web security by hashing username/password with javascript before ...
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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 ...
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317 views

How to check for a key *and* store encrypted data?

I wish to create a system wherein I store encrypted data. Users can access this data if they have the key. If they give a wrong key, they don't get access at all. If they give the right key, they get ...
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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 ...
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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 ...
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71 views

Using encryption and hashing

I'm writing a project to securely store and share passwords between users, I've been doing tons of research into encryption algorithms, CSPRNGs, hashing algorithms, key stretching etc... I just want ...
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A manual function for hasing identity?

I hope you won't close the question. Even though there are no computers involved, it is still about information and security, and I think that security experts are the ones who will be able to help ...
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2k views

Cracking Mysql 5 Hash using Hashcat

I am practicing cracking MYSQL5 hash using hash cat, however, for a reason or another, it finishes the cracking process too fast -within 30 seconds- without giving any results/errors back. I doubted ...
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217 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 ...
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272 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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220 views

How secure are hashed passwords that are salted too?

SAP Netweaver has its passwords hashed and also salted. But I read that a tool such as John the Ripper can bruteforce them. So how does security varies when passwords are hashed, in particular in the ...
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Finding out whether a website uses unsalted MD5 for password hashing

I'm working on a project where websites are analyzed and rated according to password security (factors like min/max password length, alphabet size and more are then calculated into a score). A great ...
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what does GUID have that a whirlpool, md5 or sha2 hash dont

I'm trying to understand the use of GUID and what has always left me wondering is what's so special about them that I should consider using them instead of rolling my own type of unique id. In other ...
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Creating a rainbow table with predefined text

I need to extract a password from a hash. This hash was generated by prepending and appending two different predefined strings to the password: Hash(PredefinedString1+Password+PredefinedString2) ...
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262 views

Can I combine two of SHA-3 candidates cryptography hash functions and obtain more secure Algorithm? [duplicate]

Possible Duplicate: Are different hash algorithms ever used together? For example, Is possible to combine (Concatenate or Chain or XOR) Skein SHA-3 candidate with Grostl SHA-3 candidate to ...
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618 views

What kind of hashing is generally used in log-in modules?

Do operating systems hash the log-in password? What hash function is used in Windows XP, 7, 8,Linux Ubuntu, Debian, MAC Lion OS X ,...? Where should I look to know these security considerations of an ...
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Hash, encryption of file… key? Need help [closed]

So my previous question was with some help on pcap files as I am doing a security course and we have a challenge to figure out what was going on in our network. Now one of the files I retrieved is an ...
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81 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 ...
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121 views

Why is the brute force search time for hashing algorithms 2^(num_bits / 2)?

I noticed that the brute force times (the time it takes to find a message that hashes to a given hash) of various hashing algorithms seems to be 2^(num_bits / 2). For example, people say that brute ...
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How Empathy - a messaging program, is storing my passwords

I am connected to my chat accounts via Empathy, a messaging program, and it has my password stored in it. I am really curious to know how it is storing the passwords, and if there is any they can ...
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520 views

Cracking MD5 passwords with the same salt

How long would it take to crack passwords up to 10 letters long if you knew the hashes were MD5 with a salt (that you know)?
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What are the enhancements of SHA1 compared to MD5?

I am looking for enhancements of SHA1 when its compared to MD5. But I am not talking about just heap sizes. I am talking about different enhancements than heap size. Also, I think md5 is faster than ...
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133 views

Challenge-response login without storing a password equivalent

A problem with many challenge-response login systems is that the server has to store a password equivalent. For example, if the server stores SHA1(salt + password), and an attacker captures that hash, ...
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446 views

How to identify hashing algorithm [closed]

I want to identify the hash algorithm used by an online service. What I have now is thousands of pairs of original string and result hash. Some examples: 62.152.39.195 25d10817d8d2836925 ...
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124 views

Is hashing a DLL useful to protect from DLL hijacking?

I want to make sure that the dynamic link libraries used by my application can't be replaced with other libraries of the same name, in order to inject malicious code. Therefore, I thought about ...
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697 views

What to do with .hash files when cracking WPA2

So, I'd say I'm one level above n00b. I've gotten to the point where I have accomplished a WPA Handshake (and saved the output as xxx-01.cap). I have also downloaded these hash tables (if that is the ...
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509 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 ...
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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 ...