Tagged Questions

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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3
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4answers
139 views

Record IP pseudonymously?

I'd like to be able to ban an IP from my website, but for privacy reasons I would like to not have a record of the IP itself. Hashing the IP would allow for the hash to be brute forced in mere ...
0
votes
1answer
66 views

In IKE protocol; what is the PRF? [duplicate]

In IKE protocol; what is the PRF ? What is "the generation of a key based on modeled random oracle hash functions"?
2
votes
1answer
105 views

PRF, IKE and hash function

The term PRF is mentioned in the documentation of the IKE (Internet Key Exchange) protocol. What is a PRF? What is the difference between a PRF and a hash function? What PRFs are used in the IKE ...
-3
votes
2answers
414 views

Can NSA generate all hashes for rainbow table to break md5?

I was wondering about md5 encryption. It is good, and I agree that it is unbreakable. But this is why we have rainbow tables. What if bunch of people gather together and start brute forcing and ...
3
votes
2answers
1k views

Is it a good idea to store Email addresses as hash only?

I am currently building a web service at http://write-math.com similar to http://detexify.kirelabs.org/ that should help users to get LaTeX code from drawn formulae. It is part of my bachelors thesis ...
0
votes
2answers
123 views

Asymmetric Data Storage+ No-Hash Password Storage?

Edit: removed a part of the original question; I'll break it down in a different post. I am following @Polynomial's answer to store information in a database. Here are my requirements: Only the ...
1
vote
1answer
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 ...
2
votes
3answers
550 views

Hashing speed with true random passwords

Just a theoretical question: If I had ideal users, who all provide fully random 128-bit passwords, And also, I invalidate every password shorter than 128 bits. Then would I still need a slow hash ...
2
votes
1answer
130 views

Hashed passwords for NTLM authentication

I understood that Windows users' password hashes can be exported very easily. Right? So my question is: If I can have the hashes of other user accounts (e.g. local users on my Windows machine), isn't ...
6
votes
5answers
2k views

Whenever an unhandled exception somehow makes it into production, is it safe, viable, etc. to print an encrypted stack trace to the end user?

Whenever an unhandled exception makes it into production somehow - whatever the reason - there's generally an option (especially with .NET programs) to print out a stack trace to the end user before ...
9
votes
6answers
2k views

Should I hash a password if it is randomly generated

The best practice is we should hash a user password using algorithms such as bcrpyt to protect the user, however, given the following conditions, is hashing in the backend still matters? the ...
0
votes
4answers
145 views

Password Hashing Without a Unique Salt

I have a question about password hashing. This is not a question about the the BEST POSSIBLE method of hashing passwords, but rather a more utilitarian question about what is sufficient to hash a ...
0
votes
1answer
45 views

Is it safe to use the Keccak Algorithm to create the Key for a Serpent cipher?

I like to store some configuration but would encrypt them with the Serpent cipher. Is it safe to do this? When not, what is a better solution?
10
votes
2answers
741 views

LastPass Grid Authentication vs Google Authenticator which one is more secure?

[Being a LastPass user] recently I moved to Google Authenticator instead of using Grid Authentication as a 2-factor security. For me, finding and filling letters from such a dense matrix is a rather ...
2
votes
2answers
200 views

Is it important to use a slow hash in htpasswd?

It's my understanding that the purpose of .htpasswd files is to restrict access to some files in the server filesystem. If an attacker gains access to it, he probably has access to everything else ...
-3
votes
3answers
138 views

Hashing credentials. Is hash(email+password) secure enough?

I am working on a client server application where to identify each user I was thinking of storing a single database entry: hash(email + password) In my opinion, this is enough to stop some known ...
1
vote
1answer
112 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 ...
1
vote
2answers
221 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 ...
53
votes
3answers
18k views

How can I create a password that says “SALT ME!” when hashed?

How can I create a password, which when directly hashed (without any salt) with md5 will return a string containing the 8 characters "SALT ME!". The hope is that a naive developer browsing through his ...
-3
votes
1answer
104 views

Is there a way to attack the SHA-3, GOST, and WHIRLPOOL hash functions? [closed]

Is there a way to attack SHA-3, GOST, and WHIRLPOOL hash functions?
0
votes
0answers
24 views

Length-constant password comparison in scrypt? [duplicate]

E.g.: XORing the candidate against stored then comparing against 0. Do I need to worry? (my question is much in the same style as this question: Does bcrypt compare the hashes in ...
2
votes
2answers
2k views

NTLM/LM Hashes on Domain Controller

I've noticed that when extracting password hashes from a domain controller (using Elcomsoft proactive password auditor) sometimes I'll get LM and NTLM hashes and other times I'll only get NTLM hashes. ...
2
votes
2answers
229 views

Keepass Dictionary Attack Protection Strategy

Though pretty interested, I'm everything but an expert in Information Security, please redirect me to any helpful resources if my question is stupid or correct me if my assumptions are wrong. When ...
2
votes
1answer
117 views

How difficult it is to solve a salt if knowing the original data and the hash output that uses the SHA-2 algorithm

I am reading the documentation for Kentico where it describes using hashes to validate query strings ...
4
votes
4answers
970 views

Why does MD5 hash starts from $1$ and SHA-512 from $6$? Isn't it weakness in itself? [duplicate]

I have moved this question from stackoverflow to this place. I know it may be a question about 'opinion' but I am not looking for a private opinion but a source of the final decision to keep it this ...
1
vote
1answer
105 views

Hashing password for secure storage (generating salt)

I wanted to check if the following means of generating a hash for storage of a password was secure. I have an username and password combo. In order to generate a secure hash, I am doing the ...
1
vote
1answer
631 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 ...
3
votes
1answer
90 views

Is it possible to slow down the Blue Midnight Wish cryptographic hash function?

In the Blue Midnight Wish (BMW) cryptographic hash function, is there a variable I can use to increase memory/CPU resource consumption to slow down the password hashing process? Call me crazy, but I ...
1
vote
0answers
506 views

Brute-Force/Dictionary attack against encypted file using PBKDF2 key derivation

I have been following this very useful post by Thomas. My use case is slightly different. I am developing a mobile application which requires some sensitive data to be stored on the device in a SQLite ...
-1
votes
1answer
68 views

Minimize collision risk for any hash function?

What's some good advice on eliminating collisions when hashing things? I need a unique identifier for all my users, but I want them to be private. I'm thinking of using ODIN-1 ...
0
votes
2answers
414 views

Securing passwords for REST Authentication

first post on sec so go easy. I'm developing a REST application using the Spring Framework, as as part of the requirements, we have to secure the different functions of the system to different user ...
0
votes
3answers
117 views

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 ...
0
votes
1answer
72 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.
0
votes
1answer
61 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?
2
votes
2answers
292 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?
-3
votes
1answer
51 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 ...
1
vote
1answer
176 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
vote
1answer
422 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
vote
0answers
171 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 ...
1
vote
0answers
52 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?
0
votes
1answer
50 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?
-1
votes
3answers
72 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.
2
votes
4answers
368 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
votes
4answers
370 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
votes
4answers
296 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
votes
1answer
95 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 : ...
2
votes
1answer
224 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
votes
2answers
172 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 ...
17
votes
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 ...
0
votes
1answer
50 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 ...