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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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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2answers
103 views

Why do file storage sites have a long unique id for their download links?

I'm creating a file storage site and what I would do is just have the download links format as: https://www.domain.com/[id]/[file name] //id would just be 1, 2, 3 etc. Dropbox and many others have ...
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4answers
219 views

What are the advantages/disadvatages of hashing over encryption?

I know that hashing is a one way function and encrypted messages could be retrieved if you know the corresponding key to which you encrypted the message. Other than the ability to retrieve, what ...
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0answers
32 views

Algorithm to Transaction Data Signing

Transaction Data Signing I need an idea to develop a very secure algorithm to authenticate online operations using PHP in the server and an Android app in the user's device. What is the idea? The ...
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2answers
193 views

Content-Security-Policy hash of script

<?php header("Content-Security-Policy: default-src 'sha256-".base64_encode(hash('sha256', 'console.log("Hello world");', true))."'"); ?> <script>console.log("Hello world");</script> ...
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1answer
64 views

Will my method for managing account data work?

I'm looking at whats nessecary to create a small accounts server for a video game I'm programming in my spare time. User privacy is a very important topic for me, and I don't want to keep anything ...
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3answers
90 views

What part of the CSR is hashed in order to create its signature?

I'd like to change the CSR before it is transferred to the CA without going through the CSR creation process again. To do that I need to know how to calculate the signature of the CSR after I modified ...
15
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2answers
511 views

Can client-side hashing reduce the denial-of-service risk with slow hashes?

When storing user's passwords that you need to verify against (but not use as plaintext) the current state of the art is: Hash the password Use a salt Use a slow hash function - bcrypt, scrypt, etc. ...
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1answer
150 views

Any reason I shouldn't be salting and hashing before putting through bCrypt?

I've been reading up on password storage and such, and have come to the conclusion that I need to be using bCrypt. I've got an implementation working correctly, but I'm wondering the best way to move ...
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1answer
55 views

Find hash-function if original and hash are given? [duplicate]

I was thinking whether or not you can find the hash function(s) used if you have the original message and the hash. So assume that no salt is used during the hashing process, just multiple hashing and ...
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1answer
121 views

How do we estimate the time taken to crack a hash using brute force techniques

A German hacker famously managed to brute force crack a 160 bit SHA1 hash with passwords between 1 to 6 digits in 49 minutes. Now keeping everything constant (hardware, cracking technique - here ...
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1answer
94 views

Hash leaked online

Recently I Googled the email address of one of my friends, as I was just curious of what would come up. Lo and behold, he saw what presumably is his Gmail hash. It is part of a list of 10,170 email ...
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32 views

Hashing / How easy is it to infer the original input if the a slight variation of the input, the hash result and the hashing algorithms are known [duplicate]

Given that I have an initial input that is publicly known (e.g. "ABCDEFGHIJ") a slight variation of (1) (e.g. "BACDEFGHIJ") that is used as the input to a hashing algorithm (3) an modern one-way ...
2
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1answer
81 views

Stream/Block encryption using XOR and Hash function?

Could a hash function like sha1 or ripemd-160 be used for secure key generation in a stream/block cipher? Obviously a repeated key like "abc123abc123abc123" would be bad, and a one time key pad would ...
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1answer
88 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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4answers
327 views

Can I brute-force a password hash even if I don't know the hash-algorithm used?

Can I brute-force a password hash even if I don't know the underlying algorithm? For example if I get hold of a database with password hashes and the used hash algorithm is unknown, like a random ...
3
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2answers
110 views

MySQL ENCRYPT salt is not random?

I know there's little reason to still use ENCRYPT() nowadays, what with bcrypt being almost ubiquitous and MySQL providing better hashes such as SHA1. But while dabbling with ENCRYPT() on MySQL ...
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2answers
119 views

Is there any issue using the PHP crypt() function with an additional salt?

Is my PHP authentication script secure? I noticed that the hashes start with the first two letters of the username. Could there be a security flaw using crypt() in such a way? <?php // ...
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1answer
171 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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4answers
135 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
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1answer
46 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"?
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1answer
70 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 ...
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2answers
255 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 ...
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2answers
802 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 ...
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2answers
93 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 ...
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1answer
605 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
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3answers
547 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
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1answer
90 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
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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 ...
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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 ...
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4answers
99 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 ...
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1answer
43 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?
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+50

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 ...
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2answers
147 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 ...
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3answers
110 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 ...
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1answer
83 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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2answers
141 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 ...
52
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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 ...
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1answer
81 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?
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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
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2answers
505 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
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2answers
174 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
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1answer
83 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 ...
2
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4answers
314 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
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1answer
90 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
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1answer
327 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
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1answer
61 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 ...
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204 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 ...
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1answer
54 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 ...
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2answers
164 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 ...