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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What is a good enough salt for a SaltedHash?

Since I'm hashing all passwords with each their own salt, is there a benefit to the salt being really random, or would an incremental counter or a guid be good enough? Also, is there a benefit of ...
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2answers
473 views

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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1answer
502 views

What encryption hash function I should use for password securing? [duplicate]

Possible Duplicate: How to securely hash passwords? What is the best encryption algorithm? MD5, SHA1, SHA2 or maybe something else? Can you explain me why?
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3answers
245 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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2answers
780 views

Knowing Hash Algorithm from Hashed String

I found an application which stored its password in database as: A69F00623BE6B8 It's a 14-character string length. How do I know this password algorithm? What's the keyword to describe this ...
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4answers
441 views

Are there vunerabilities with this authentication mechanism?

I am trying to come up with a way to implement token-based authentication for a REST API without the need for SSL. The goal here is to avoid sending any sensitive information across the wire. I was ...
1
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0answers
319 views

what is this hash type? [closed]

Actually I have this hash but I don't know what cryptographic hash function generated it. 4753305A7A673D7A5A442156 I know password is 12345678 I extracted this pass from PLC device Mitsubishi
11
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3answers
7k views

What's the advantage of using PBKDF2 vs SHA256 to generate an AES encryption key from a passphrase?

I'm looking at two comprable pieces of software which need to encrypt data on disk using a passphrase. One uses PBKDF2 to generate the encryption key from a passphrase, while the other uses two rounds ...
38
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2answers
4k views

Pre-hash password before applying bcrypt to avoid restricting password length

Good practice is not to unnecessarily restrict password length, so that appropriately-long passphrases (perhaps 35-45 chars for 6/7 dicewords) can be used. (See e.g. Should I have a maximum password ...
2
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4answers
400 views

Fingerprinting Hash Function

For the purpose of fingerprinting data with the least chance of collision will combining the length (as a 32 bit unsigned integer stored in addition to the hash) of the input data and/or sampling a ...
3
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3answers
402 views

What pros and cons are there to a one-time random salt between client and server?

In researching on best practices in hashing passwords using a salt I came across a presentation on slideshare. The approach outlined is as follows Client requests login page Server-side code ...
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1answer
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efficient 16 bit hash [closed]

I'm looking for a way to make a 16bit ID out of approx 100 bits of data. The solution should be easy to implement, or should already be implemented in c++, should be quick to evaluate, and most ...
2
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1answer
109 views

What is the meaning of 'adaptative' and 'over time it can be made slower' in the context of the bcrypt algorithm?

I'm reading the wikipedia definition about bcrypt but I don't understand the meaning of 'adaptative' and 'over time it can be made slower'. Can someone explain what they mean in this situation?
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3answers
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Using MD5 for malware ids: collision attack risks?

It has been known since 2004 that the MD5 hash is vulnerable to collision attacks (update - not "preimage" attacks - my mistake....). Yet it still seems that people are using it to identify malware. ...
4
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2answers
1k views

What is better salted hash or openssl encryption?

Im using php and I was looking to store passwords in a mysql database. I was wondering what would be safer to use a salted hash or openssl encryption? If i use a unique random generated salted hash ...
3
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2answers
489 views

Security of GPG encryption with AES and MD5 if MD5 is broken

I have a file encrypted with gpg, using AES256 and MD5. Suppose that the MD5 hash function is broken, but not the AES cipher. Does that make it easy to crack decrypt the file?
8
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1answer
787 views

Is there repetition in the Solaris 11 hash routine? Can I add some?

Solaris 11 now uses SHA-256, so we can have longer than 8 character passwords now, by default. That is nice. I'll just make it clear that this password is never used as a line of defence. Only a ...
5
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1answer
3k views

Is BCrypt enough when saving a password into a database?

In order to allow users to connect to my website, I encrypt their password using BCrypt since it is one of the slowest algorithms to decrypt (making a compromised database longer to be decrypted). ...
2
votes
2answers
688 views

Time needed to generate an RSA signature of a document

How does the length of the RSA key and the size of the document affect the time it takes to sign a document using SHA-1 and RSA? I used CrypTool to check it, but the time does not appear to be larger ...
3
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2answers
415 views

Why is the diffusion property important in hash functions

I have always heard that A change in just one bit of the original text shall change half of the bits of its hash. I think this property is called the diffusion property. However, I wonder why ...
15
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7answers
8k views

What are the realistic, and most secure crypto for Symmetric, Asymmetric, Hash, Message Authentication Code ciphers?

I'm interested in updating this two pronged question for 2011: What cryptology is most appropriate for low-powered devices (such as a cellphone), and yet still effective? What cryptology is most ...
1
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1answer
189 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 ...
3
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1answer
433 views

Cookie based session variables

I have a situation in which I cannot use a server-side session, but must allow users to log in, and for their logged in state to be persistent between queries. As with anything that involves crypto ...
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1answer
343 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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6answers
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Is PBKDF2-based System.Cryptology.RFC2898DeriveBytes() “better” for Unicode Password hashing than traditional methods?

When is it appropriate to use RFC2898DeriveBytes versus a typical hash? Update I now understand that a KDF is typically used to create a symmetric key for possible use in encrypting a stream. I ...
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2answers
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Authenticated Encryption vs. contained and encrypted checksum/hash?

So I read through http://en.wikipedia.org/wiki/Authenticated_encryption and http://www.cryptopp.com/wiki/Authenticated_Encryption and I don't seem to be following the concept. From the simple ...
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4answers
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Does symmetric encryption provide data integrity?

Let's say I have one server that encrypts a file with a symmetric key, e.g. AES-CBC, and sends it to clients that decrypt it. Does that provide data integrity when decrypted? Or is it possible for ...
3
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2answers
464 views

What algorithms can be used for device pairing?

I am to implement a system where android devices connect to a central server and have to register with different user accounts, so I have decided to create a pairing dance similar to what can be ...
0
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1answer
204 views

Securing communication

The problem: I have an open-source client (a Firefox add-on written in JavaScript) and a server containing somewhat sensible user information: username and user history (all from YouTube). The client ...
2
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1answer
200 views

How do we encrypt a password using another password?

Heys all I've got a nub question, I was wondering What does it mean to encrypt a password using another password? For example I want to encrypt a password foo using a password bar, does it mean that ...
2
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2answers
422 views

Is it secure to have one salt or generate and send it over the air?

To authorize user I'm sending salted hash over the air. My question it is more secure to obtain randomly generated salt (but send unencrypted), or have one salt on client (desktop application) and ...
42
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5answers
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Password security in databases - today still best practice? [duplicate]

Possible Duplicate: Which password hashing method should I use? There are a ton of great posts about password security in databases on stack overflow and on other sites and as I am ...
3
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1answer
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How to implement WSS UsernameToken when password on the server is salted and hashed?

I'm currently trying to write a web service for customer and requirement is to use WS Security. On their server side, they have passwords stored as SHA-1(salt+password). According to WSS spec, ...
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3answers
645 views

DNS queries with hex string that is a SHA1 of a domain name! Is it a malware?

My computer does a lot of queries to strange domains such as: 56cea5c2b408989ab067adcb787d0f99209bbe07.mydomain.com The strange thing is that 56cea5c2b408989ab067adcb787d0f99209bbe07 is the SHA1 of ...
0
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2answers
164 views

How much security should I use for my web application?

My question is, for a "normal" site, what do you think is enough to secure against methods used by "script kiddies"? For example, SQL injection, XSS, and stuff like that. Same question for password ...
8
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5answers
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What is the problem with chain hashing?

Let's say that my password is a single character: "a". Couldn't I chain hash it 1000 (or more) times and make it nearly invulnerable to rainbow table attacks and brute force? Why isn't this ...
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2answers
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Revisting the Username Hash

There are a few questions which ask for inputs on the wisdom of storing (possibly salted) username hashes for the purpose of authenticating end user access to some information resource. Most of the ...
5
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2answers
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Zero padding in HMAC

Section 2 of RFC 2104 defines the key used in HMAC should be padded with zero bytes up to the block length of the underlying hash algorithm. Isn't this a potential security vulnerability since any key ...
4
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2answers
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PHP Vulnerability May Halt Millions of Servers - max_input_vars!

Recent version of PHP 5.3.9 has been released a couple days ago, and Hash Collisions have been fixed, most of the servers actually didn't upgrade their server until now, including my website's server. ...
3
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3answers
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Is it safe or even common to cache bcrypt checks in-memory

In a web application that (as a side effect of implementing the password anti-pattern) stores passwords, one recommendation is to bcrypt to store them (or computationally expensive one-way salted ...
4
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1answer
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Rainbow tables, generation and lookup, preferably using GPU

1a) What software can I use to generate my own rainbow tables, preferably software that can utilize CUDA or ATI Stream? One of the reasons I want to make my own, is that I want to use a specific ...
17
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1answer
2k views

Timing attacks on password hashes

Timing attacks can have a devastating impact in scenarios where the secret is involved, often in cases where byte-wise array comparison is used. Now there are those that advertise using constant ...
6
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3answers
831 views

Global check of input/output of known hash functions

Is there a website, application, or script that will allow you to give an input/output for a hash function, run these against known functions, and return any matches? Here's one attempt to list the ...
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1answer
2k views

Can Solaris' shadow hashes be created by better algorithms than the default DES-based hash?

By default, Solaris uses Traditional DES to encrypt password hashes in the shadow file. Is there a way to harden the security by changing this default behaviour and make it to be hashed using a ...
4
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2answers
214 views

Salting a public hash

Does it make any sense at all to salt a hash which might be available publicly? It doesn't really make sense to me, but does anyone actually do that? UPDATE - Some more info: An acquaintance of ...
4
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3answers
959 views

Does Hash/Salted password really help when DB is compromised?

I came across this article and got a basic understanding hash, salt and brute force attack. My question is in the article, the author emphasises how hard it is to reverse the hash/salted password to ...
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998 views

Are different hash algorithms ever used together?

I was wondering if different hashes (e.g. md5(sha1($data)) ) are ever used together for data security and if there was any reason for it (either positive or negative answer).
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Am I required to hash passwords

Is one required to hash passwords by law in the US or elsewhere? If not required by law, are there legal ramifications if unhashed passwords are stolen? If not required in the US, but required in the ...
3
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1answer
112 views

What are the implications of omitting the username in Secure Remote Password's verifier?

I consider implementing a Secure Remote Password (SRP-6a) verifier that omits the username from the x key hash. The intention is to allow authentication with multiple alternate user identifiers such ...
3
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2answers
429 views

What is considered a reasonably high iteration count?

I copy-pasted a function that implements the PBKDF2 hashing algorithm in PHP. The function asks for the amount of time that I would want it to loop in order to produce a hash. Now, I'm wondering, ...