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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247 views

What if I develop my own hash algorithm to create strong passwords from easy ones?

I came up with this idea but I cant figure out if it's good or bad, maybe you can help. My goal is: I want to create extremely strong passwords for my main accounts (gmail, skype and so on). I want to ...
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2answers
82 views

Is it unsafe to hash one password with more than one salt?

I'm asking my question here since I was not able to find an answer anywhere. I have written a piece of software which stores pretty delicate passwords. I have used BCrypt as hashing algorithm with an ...
0
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1answer
108 views

Advice on using encryption and hashing

I'm going to rephrase a question I asked earlier, as I don't think anyone understood what I meant. Bascially I'm writting a web based password locker, which can have multiple accounts; so that users ...
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1answer
64 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 ...
2
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3answers
104 views

Client-side hashing of password before sending it from login form [duplicate]

I have just realized, that my web application is sending unencrypted passwords from login form. It's just like that -- I've analysed, that string sent by user from login form is hashed with MD5 (which ...
3
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3answers
642 views

Is this a secure way of storing passwords? [duplicate]

So a couple years ago when I was learning basic back-end web development, I found a tutorial for creating a basic log in system. I haven't done much modification to the code since, but I have the ...
3
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4answers
592 views

How to properly anonymize data, if hashing isn't enough?

Today there are news on Bruce Schneier's blog and ArsTechnica about how NY City released information about Cab/Taxi drivers, their trips, and so on. Basically, sensitive information was simply MD5 ...
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1answer
63 views

Using hashed password as secret key for hmac to avoid exchange of secret between server and client

I'm currently trying to improve our API to be more restful, therfore avoid any state on the server. I want to accomplish this with a hmac token, appended on every request. The hmac will be made with ...
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3answers
56 views

How to secure Password and Salt on a deployed application

I have a question regarding one step of protection more than salt/hash. I work on an application that is distributed to many clients and then deployed on their networks. If I set a password on one ...
16
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8answers
3k views

Won't all hashes collide after enough iterations (with a static salt)?

We all know that we're supposed to take a fairly slow hashing algorithm, salt the password, and run the hash for many iterations. Let's say that I'm following almost everything except for one rule, ...
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1answer
100 views

I know scrypt is newer than bcrypt, but is there any reason it would be weaker?

From what I read, scrypt is (on paper) more secure than bcrypt, but it's pretty new so it's better to let it get time-tested and scrutinized first. However, is there any good, compelling reason to ...
11
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7answers
720 views

Aren't password managers still incredibly risky?

I understand the utility in having one application remember a bunch of long, randomized passwords, but all you'd need is one well-placed phishing scam or a keylogger and they get all the keys to the ...
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1answer
174 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)?
2
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2answers
108 views

Breach informing

I am a staff member of a large fanfic site, but not the head administrator with control over the site itself. Recently, we had a security breach and the databases were copied, which included the ...
4
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3answers
149 views

Is it good practice to SHA512 passwords prior to passing them to bcrypt?

I want to allow any-sized passwords to be allowed to be submitted. I currently use bcrypt as a key derivation function for passwords, however I have realized that it has a maximum input length of 72. ...
9
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3answers
4k views

How often do two users use the same password

If no two users use the same password, then in theory salting the password hash is not needed. How often, in practice, do two users have the same password?
70
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8answers
9k views

Convincing my manager to use salts

My manager says we don't need to salt our passwords because people are not likely to use the same password because they all have different native languages, in addition to the websites they are active ...
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1answer
65 views

Ldap differences between {crypt} and {CRYPT}

I recently stumbled upon some password entries in LDAP marked with the {crypt} scheme. Since all recent entries are {CRYPT}, I was wondering what the differences between the hash algorithms are.
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2answers
212 views

Storing multiple hashes to prevent collisions, security risk?

This is all just for curiosity's sake, so discussion on which hashing algorithm is harder/better/faster/stronger is irrelevant. But my question/thought is this.. With regards to password storage, and ...
1
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1answer
148 views

Theoretical home grown password options, or what is it that SCrypt, BCrypt, PBKDF2 does that is so special?

I'm developing a personal web framework, nothing internetty, and probably not even anything that will ever go on my personal LAN. And looking for password advice people seem to only recommend those ...
42
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5answers
4k views

Is it safe to tell your users what kind of hashing algorithm you use?

For example, on the user registration page, is it safe to tell people "Your password will be stored as a one-way hash using the (whatever) algorithm."
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4answers
88 views

Is salted MD5 or salted SHA considered secure?

Is using something like bcrypt or scrypt necessary? The hashes are so much longer to store in a database. Can one get away with using salted MD5 or SHA and still be secure?
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4answers
157 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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2answers
86 views

Is a long salt usually sufficient for security purposes, even with MD5?

I always hear that MD5 is too fast for effective password crypto because you can crack up to 6 characters very quickly (or is this number higher now)? But what if the salt you use is really long and ...
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2answers
58 views

Why RSA signatures based on the hash of the message? [closed]

Why RSA signatures based on the hash of the message rather than the message itself?
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2answers
441 views

Protecting hidden form fields

The scenario is as follows: An application has a web interface through which data can be configured. The data to consider for this question is Users with a many-to-many relationship with Groups. ...
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1answer
52 views

Log file checksums

I am told that you can tell if the log file (like from ripping a CD) has been modified by its checksum. How? How do you bypass this if you wanted to modify it?
2
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1answer
64 views

Identical lanman hashes on AD accounts?

I ran metasploit's smart_hashdump module against my (2008r2) domain controllers, trying to find any accounts that may still have lanman hashes in place. These should have been disabled long ago. I'm ...
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1answer
109 views

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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2answers
76 views

Security of this account login system

I have an idea to implement a account system using email and passwords for games. Im intending to have the account creation and forget password systems on a webpage. So if users will have to access ...
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2answers
40 views

Can I save & store a user's data in a way that proves that the information has not been altered, and that the timestamp is accurate?

There are many situations where the validity of the timestamp attached to a certain post (submission of information) might be invaluable for the post owner's legal usage. I'm not looking for a service ...
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2answers
57 views

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
117 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 ...
0
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4answers
283 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
39 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 ...
2
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2answers
297 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> ...
4
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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 ...
1
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3answers
108 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
532 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
169 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
56 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 ...
0
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1answer
137 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
98 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 ...
0
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0answers
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
89 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
99 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, ...
3
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4answers
358 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
124 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
143 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
233 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 ...