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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hash function notations and existing cryptographic hash algorithms [migrated]

I am implementing Role-based access control by referencing the paper Enforcing Role-Based Access Control for Secure Data Storage in the Cloud. In page 6, they have mentioned to choose hash functions ...
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2answers
28 views

How to brute force this token in php, if it is possible

it is possible to brute-force this token (MD5 Hash) of the following script (PHP) in a realistic time (0,5h - 24h)? If the answer is YES, how could I do it, for example with PHP or Python? $time = ...
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4answers
50 views

How are salts safe in the database? [duplicate]

I have read many and many of this type of question on the security stack community before I asked this question, but one thing that made me mad about salts and saving it in database is this ... I will ...
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0answers
22 views

Recommended Crypto Security Setup (Implemented Algorithms)?

Firstly I'm not a crypto expert, however I know how to use algorithms that other people have defined before in practical usages, that is, as long as they live up to their promises. The thing is that ...
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2answers
48 views

Does a hash of a 32-bit integer make a better hash salt than the integer itself?

I have a scenario where I already have a table of resource passwords stored as unsalted 128-bit hashes. I'm unable to force owners to provide new passwords, so I'm trying to mitigate the situation by ...
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2answers
93 views

How secure is the hashing/salting/stretching process as described in this diagram?

Question I was just brainstorming about the hashing, stretching, salting part of the user password in the authentication process and I want it to be as secure as possible (no matter how paranoid that ...
2
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0answers
84 views

Any vulnerability in .net implementation for C# object.GetHashCode?

I've already asked this question on SO, but I think that this forum is more appropriate to discuss security issues. My point is that most OO languages has a way to get a unique hash code for an ...
1
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1answer
58 views

How secure is the UNIX sha_crypt as a password storage algorithm? [duplicate]

So I have been working on password storage, especially on the algorithms to use (and to not use). Most people are recommending scrypt or PBKDF2 for valuable reasons, but I have not seen any talks ...
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2answers
132 views

How long would it take to generate a file to match a hash? [duplicate]

A individual file only has a single hash of any specific byte length. But an individual hash can represent a large number of different files. Given a 256 byte hash, how long would it take to ...
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2answers
71 views

Website says my new password can't be used because it is the same as an old one [duplicate]

What are the risks of storing (in hashes I guess) all the old passwords? Why would a company chose to not delete old passwords? Why not let users reuse old passwords?
7
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2answers
160 views

Is there any recommended approach for “upgrading” MD5 hashes to something secure? [duplicate]

I'm currently dealing with a couple of user accounts containing MD5 hashed passwords. These accounts got migrated from an old system into our current system which uses PBKDF2 for password hashing. I ...
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0answers
75 views

How can I decode hashed passwords? [duplicate]

I have access to a Microsoft SQL database where passwords are stored like this: bZB056KMVxCXa/D8zd3q/g== How can I decrypt this hash? I don't know which algorithm is used for this hash.
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1answer
86 views

How to detect if a crack is cracked only or cracked and binded with other executable? [closed]

Viruses are often spread using cracks. I want a quick and dirty way to know if the cracks are not binded with other executables The process goes like this. The program is installed using the ...
0
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0answers
26 views

ISO 9564 Approved Encryption Algorithms for PIN, why symmetric block ciphers?

I am currently researching best practices in designing a potential PIN management solution for a financial services application and began looking into ISO 9564 as a source of requirements. One of the ...
27
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3answers
4k views

Can I share what password hash function I used in a public report?

I have developed a web site during an internship, using a database with accounts. I used the crypt() method from PHP, with a secured algorithm plus salt (found on the web with a lot of feedback). ...
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votes
1answer
129 views

Where do webstites store the hashes? [closed]

I understand that lots of websites store passwords in hashes but where do they actually store the hashes? How can a website compare your hashed version of a password with theirs? Is it stored ...
1
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1answer
73 views

Is using dynamic obfuscation and peppers for password hashing a good idea?

I've read now the whole day about password hashing and secure authentication and though I read very often that mostly every own algorithm makes the proven hashing methods just less secure, I just got ...
1
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1answer
88 views

Password Encryption For PHP 5.3 or Should We Update to 5.5+?

I'm trying to hash passwords for our company site. After testing on a local Apache server that has PHP 5.5.9 and everything working as expected, I went to test on our live server being hosted by ...
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0answers
36 views

How to extract the hash from SMB

I have a running PC which I need to test against.It is running Windows with SMB enabled. When capturing using Wireshark while connecting with an incorrect password I see packets being sent to / from ...
0
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1answer
31 views

If domain admin account's NTLM hash is compromised, can it be used to access any machine in network

If a hacker able to get local admin rights and then from there local domain admin's NTLM hash. Can he use this hash without cracking, to access shared folders in the network and the default C drive ...
-1
votes
2answers
104 views

Secure password generation for different websites [duplicate]

I came up with the idea to generate passwords for internet sites by the following shema: $masterpassword $hostname $TLD hashfunction($TDL.$masterpassword.$hostname) So the actual password is a ...
1
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1answer
63 views

Firmware protection scheme

Edit: I have found a scheme that fits my limits (little memory, only AES is available): AES-CMAC described in RFC 4493 (just remember to use different key for encryption and MAC ;) . I am working ...
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3answers
259 views

why don't we store passwords in a database using encryption instead of hashing? [duplicate]

hashing is a one way method, if a user lost his password he will never be able to get that password from the server, so why don't we store passwords in a database using encryption instead of hashing?
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1answer
138 views

Which file encryption algorithm is used by Synology's Cloud Sync feature? [closed]

I'm trying to find out which encryption method is used by a piece of software I use, viz. the 'Cloud Sync' feature of Synology's DSM 6.0 running on a Synology NAS. (Background. This Cloud Sync ...
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0answers
6 views

Calculating probability of finding collisions in an invertible hash function [migrated]

Assuming we have an invertible hash function H that takes inputs of size 2n and outputs hashes of size n, I use the following algorithm to find collisions: Choose a random M as input. Compute its ...
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2answers
94 views

Will hashing a password, and then splitting it into multiple db fields increase security? [duplicate]

I've been reading up on Password hashing, and it seems like there is a lot of opinions on "What's right." I'm curious about the possibility of storing a split of a Hashed password in multiple user ...
34
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5answers
5k views

Should I trust a website which uses a SHA-1 HTTPS certificate?

I am on a website where I need to pay for something. This website has the following warning in the top left: This site uses a weak security configuration (SHA-1 signatures) so your connection ...
0
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0answers
17 views

Securing FTP Creds in a Java Open Source API

I've written a basic Java API and source code must be released to a small community for the application to function correctly. The Java API helps developers track data for their running scripts and ...
0
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1answer
74 views

Possible to take hash from know result and algorithm?

I am trying to build a casino site in PHP where users can play roulette. I found this algorithm that I want to use to "roll" numbers: <?php $secret = '...
0
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2answers
147 views

store passwords as one-way-hash, or just use it as an AES key?

I want to store some data so the only one who'll be able to access it is the user itself. Here is my idea: when user registers, his password will be hashed in SHA256 (so it'll fit as an AES key), and ...
1
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1answer
109 views

How to implement iterations when hashing passwords?

To securely hash passwords, algorithms such as PBKDF2 do many iterations of a common hash such as SHA1. Are there certain ways that these iterations need to be done to be safe? In particular, from ...
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0answers
19 views

How do atom's apm and npm verify package integrity?

Are there built in verification methods to make sure the packages contain the correct code? Do they use a hash of some sort?
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1answer
88 views

How does JDBC send passwords to the server?

I am really curious about how JDBC sends passwords to the server. While I understand that is simply an API and it depends on the implementation, are they usually hashed and then sent to server? If I ...
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1answer
35 views

Possible number of collisions in a hashing function with constant message size

Jumping to conclusions from my question, can we predict possible number of collisions for a given message in a given hashing algorithm. Say I am using SHA-1 which outputs 160 characters string, and ...
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1answer
57 views

Shouldn't multiple images always exist even in most powerful hashing algorithm?

I have a confusion in mind that since in hashing we transform a large string into a smaller fixed size string, so its unlikely that any large string has a unique hash. There had to be collisions and ...
2
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0answers
47 views

How exactly does “Apache Shiro's” hashing work when using a Desktop-Client

I was looking at this question How does storing hash passwords work? and every answer essentially says that Hashing is done via the server, or most of it should, as that is the safest way to do it. ...
13
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1answer
3k views

Should I hash my passwords even if I am only allowed to generate limited traffic?

At this moment I'm busy working on an webapp with a friend of mine. The main problem we have is that we are only allowed to generate 50 GB a month in datatraffic. My question is: Does hashing the ...
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1answer
84 views

Time to break SHA-512 [closed]

From http://stackoverflow.com/questions/6776050/how-long-to-brute-force-a-salted-sha-512-hash-salt-provided, to break SHA-512 with brute force strategy, it require 3,17 * 10^64 years. It is almost ...
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2answers
438 views

How to store the access token / password reset token in the database?

I have an access code that is sent to users so that they can access the site in one-click. From terms of access it's very similar to the password reset url, so I assume the same assumptions apply. E....
6
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2answers
812 views

Is it safe to publish something encrypted with a password if you make it insanely difficult to crack?

Let's say you have a very important private key that you don't want to lose. You think of posting it to http://pastebin.com/ but then relize that elimanates the point. So you think of encrypting with ...
15
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2answers
1k views

What's the difference between a hashed and an encrypted password?

Alright, so I know this may sound dumb, but I'm having a hard time understanding what an encryption would be since it's different from a hash. I've read up on it, but I'm still not quite sure. So, I ...
35
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8answers
4k views

Find matching phone numbers without actually knowing them

We have a mobile app that, given two users, needs to let them see what common contacts they have based on their phone numbers. How can we do this in a cryptographically secure way and respecting the ...
0
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2answers
96 views

How do data breaches of account login information end up in plaintext?

For example, see this story. Am I missing something here? Are the login details actually still encrypted? I don't understand how it is possible for a data breach of what I assume is encrypted ...
3
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2answers
84 views

For high entropy credentials, is SHA256 hashing good enough?

Let's say I've got a database of high-entropy credentials (e.g. 256-bit random values) used as API keys by clients. I'd like to hash them in my database so that a database compromise doesn't allow an ...
1
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1answer
55 views

Value of hash in digital signature

I'm hashing using SHA 256 and signing a payload with a private key.The payload does not contain any password and would be HTTP(S) POSTed to server side. The payload contains some dynamic and constant ...
0
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2answers
52 views

How to properly hash a key? big vs small digest

We have to roll (decommission) database access keys often, but it's important to know which key each system is using in order to avoid removing a key in use thus creating unavailability. We want each ...
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0answers
52 views

Which is the correct algorithm while checksumming a portion of code?

As part of my research, I came across a technique in a paper which applies checksumming on a portion of code. I want to implement it. Here is the research paper which talks about the checksumming ...