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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Techniques to make a login page safe without using SSL

I am developing a web page where people can write and comment things (no personal informations required) and I need to put a log in form so users can see all their actions on my web page. My idea is ...
23
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4answers
4k views

Do I have to hash users' IP addresses when I log them?

I have read a lot of users saying that you have to hash IP addresses - and a lot of others who say I don't have to because it is not private information. I use IP addresses for identifying users, ...
0
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2answers
58 views

Is it safe to use a derivative of a password as a salt

I know for a fact that salts are an important part of storing a password securely in a database. Most people store the password hash, and the salt that was used for it. This, I have learned, isn't ...
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5answers
450 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 ...
2
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2answers
92 views

John the Ripper not identifying a password contained in the username?

I have uploaded a screenshot of what exactly is going on, here: http://i.imgur.com/bJSv7C8.png I can see that single-crack mode includes a rule that looks at the username, and "slices" it to identify ...
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1answer
72 views

Which PHP encryption method is most incidentally-secure?

just started researching on the latest PHP encryption methods, I've found out my favorite algorithms are compromised. MD5 is no good, SHA-1 has "found flaws", SHA-512 isn't "meant for passwords", ...
11
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4answers
2k views

Is there a length beyond which increasing password length provides no additional security?

Assuming that the password is stored hashed and salted, and that it is a string of random characters, is there a point where adding to password length doesn't add security? Since the hash will have a ...
0
votes
1answer
108 views

Good password hashing algorithm compatible with PHP and Linux apps

I'm looking for a password hash method for a new server system. The hashes must be generated from PHP code and verified from PHP as well as by a number of applications on a Linux system. I know that ...
1
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0answers
10 views

How were shift amount constants in MD5 found? [migrated]

The md5 specification gives a series of 4 rounds to execute over a 16-word block. Each round has a repeating sequence of 4 shift amounts (s in [abcd k s i]) : 7, 12, 17 and 22 for the round 1 5, 9, ...
19
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5answers
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Does too long a salt reduce the security of a stored password hash?

Suppose we have passwords that are statistically 7-8 characters long. Is appending a 200 character long salt less secure than a 5 character salt, because of the similar hash function inputs? I was ...
281
votes
4answers
84k views

Do any security experts recommend bcrypt for password storage?

On the surface bcrypt, an 11 year old security algorithm designed for hashing passwords by Niels Provos and David Mazieres, which is based on the initialization function used in the NIST approved ...
4
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2answers
58 views

What's the best way to transform sensitive account numbers

I work on a web application that manages information about transmission setups and processes client transmission statistics to generate billing charges for the services used by these clients. The team ...
9
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2answers
1k views

“Official statement” on php.net : CRYPT_BLOWFISH is strongest hash algorithm. Why?

First: I asked this question on stackoverflow and was kindly asked to post this here again. See the original question here. According to the [early] doc pages of the new PHP 5.5 password ...
3
votes
1answer
177 views

Improving magnetic stripe card security with a “magnetic noise” hash?

I was reading the wiki on magnetic stripe cards when I stumbled across this sentence: "Magnetic stripe cloning can be detected by the implementation of magnetic card reader heads and firmware that can ...
1
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2answers
59 views

A secure way to encrypt a connection between 2 clients securing against both passive and active adversaries

Recently I got interested in encryption and the methods behind them. So for a fun / school project I am building a program in python to encrypt data between two clients (chat and files). I'm just ...
1
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1answer
39 views

Identifying hash format caputred via Metasploit

When I use the nbns_repsonde module in metasploit, and set it to write captured responses to a file in the john format, I get a file with lines such as this: ...
0
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0answers
10 views

Is it possible to pass the hash with a hash captured from spoofing NBNS responses?

I know that it is possible to use a hash obtained from the Windows SAM in a pass the hash attack, simply setting the hash for the SMBPass paramter for various modules in metasploit. Can a hash ...
0
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1answer
42 views

PHP: Save e-mail address hashed or plain [duplicate]

I've been wondering about something, is it more secure to store an encrypted (hashed with password_hash) email address in the database, or just as plain text? I've google'd this matter and saw that ...
4
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1answer
169 views

Does password-hashing “busy-work” need to be cryptographically secure

All modern password hashing schemes are deliberately designed to include a huge amount of "busy-work", to limit the speed with which an attacker would be able to conduct password hashing attempts. ...
28
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11answers
1k views

Does hashing a file from an unsigned website give a false sense of security?

Consider this. Many websites with software downloads also make available MD5 or SHA1 hashes, for users to verify the integrity of the downloaded files. However, few of these sites actually use HTTPS ...
2
votes
1answer
148 views

Reverse Engineer this basic Hash using known answer?

Little background: I forgot one of my CCTV accounts password, so used the admin account to create a new one. However I can't access the old one as it's not possible to change a user account password, ...
0
votes
1answer
63 views

Please help clarify password hashing - salted, multiple iterations of MD5 vs bcrypt/sha2, etc [duplicate]

I was reading an article about the Ars Technica hack here and had a couple of questions. The commenter said: "PHPass uses salted and iterated MD5 to hash passwords" My question is that if I were ...
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0answers
38 views

Possible hashing scheme [migrated]

Plaintext(binary) : 10101100 //very short for easy understanding Suppose we have 4 predefined schemes/functions, rotate (101 -> 011) flip (1101 -> 1011) exchange (11011 -> 10111) stretch (1100 -> ...
0
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2answers
51 views

Separate database column for salt

Is it advisable to store the salt in a separate database column or should we concatenate it together with the password? Is there any difference? I have come across implementations of both types. ...
80
votes
6answers
26k views

Password Hashing add salt + pepper or is salt enough?

Please Note: I'm aware that the proper method for secure password storage hashing is either scrypt or bcrypt. This question isn't for implementation in actual software, it's for my own understanding. ...
292
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11answers
52k views

How to securely hash passwords?

If I hash passwords before storing them in my database, is that sufficient to prevent them being recovered by anyone? I should point out that this relates only to retrieval directly from the ...
1
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1answer
243 views

Tracking IP address to prevent abuse without logging user metadata

I am trying to balance good security practices against excessive logging of user metadata / Personally Identifiable Information. I am constructing a web app that tracks IP addresses to prevent abuse, ...
10
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1answer
322 views

Torrent “bad seed” attack by Sony, how does it work?

Sony recently saw a large amount of data stolen. In order to prevent the stolen data from being spread using torrents, they are doing what was called a bad seed attack. What is this attack? Is this a ...
9
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 ...
2
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0answers
37 views

HMAC-SHA256 Transaction signing [closed]

Can rfc6238 be used for transaction signing by concatenating the random seed string with transaction details (such as amount and target account number) ? Could a transaction authorization 8-cipher OTP ...
1
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0answers
44 views

Passing the hash with metasploit and psexec not working - why? [closed]

I am currently doing a penetratiion test, and have captured a bunch of NTLM hashes via NBSN spoofing. An example (this is not taken from what I captured, and is random but the format is the same) ...
1
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2answers
397 views

PBKDF2: can the salt be known from the hash?

I understand that some KDFs bundle the salt with the output, such as bcrypt (modular crypt format). In PKCS5_PBKDF2_HMAC (specifically, looking at OpenSSL implementation) with a single iteration, is ...
1
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1answer
52 views

find out the algorithm based on some examples?

I have an OTP generator that receive two numbers less than 99 as input and return an 8 digit number as its output. I know it has a simple algorithm. because its processor is just an ATMEGA8 micro ...
0
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1answer
42 views

Verify CDN javascript's integrity

CDNs speed up the loading of websites by allowing caching for frequently used javascript libraries like jquery. How do we know if they have modified the javascript before serving it to my clients? ...
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votes
1answer
48 views

Authentication protocol based on hash function [closed]

Is it possible that Alice can authenticate Bob without using any secret information except her password, i.e they don't share any thing else. If so, how can I authenticate Alice and ensure the ...
2
votes
1answer
119 views

TrueCrypt VS LUKS Bruteforce Resilience

I have been researching LUKS vs TrueCrypt topics -- my only concern is security, but most of the discussions I see focus around usability / interoperability . I know TrueCrypt has a bunch of nice ...
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votes
1answer
40 views

Why not use md5 auth mechanisms for IMAP over TLS?

I'm using Dovecot for IMAP connections. I've read a lot of tutorials on how to set up Dovecot, and a lot of them said to only allow: auth_mechanisms = plain login Why should I not allow *-md5 ...
3
votes
1answer
67 views

Are there any ways to leverage NTLM V2 hashes during a penetration test?

I am on a penetration test at the moment, where LM/NTMLv1 hashes are disabled. I have captured a number of NTLMv2 hashes via NBNS spoofing, however was unable to crack them after running them through ...
2
votes
3answers
135 views

Are there any flaws in this two way cryptographic function?

I created a simple two way cryptographic function which allows you to encrypt a message and decrypt it with the same key. Here's how it works. Split the message into an array of 32-bit (or something ...
3
votes
1answer
79 views

Do I need a salt when hashing a randomly generated password?

I have passwords stored in my database that are very long, unique and generated by a CSPRNG. Do I need to use a salt before hashing them? My understanding is that usually you use a hash function in ...
31
votes
5answers
2k views

Password Storage - Self Encryption vs Hashing?

Self Encryption: Encrypting a password using the password itself (as a symmetric key). Basically, by doing this, I'll get random data as an output. Now, in order to retrieve the password from this ...
0
votes
1answer
51 views

PKI - Security concerns when changing a certificate hash algorithm

Suppose I want to change the hash algorithm used for a certificate signature (ex: SHA1 to SHA2). Is it better to revoke the previous certificate and issue a new one with expected hash algorithm ? Or ...
12
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6answers
3k views

Client side password hashing

Edit: Updated to put more emphasis on the goal - peace of mind for the user, and not beefing up the security. After reading through a few discussions here about client side hashing of passwords, I'm ...
22
votes
4answers
5k views

What is SHA-3 and why did we change it?

On the 2nd of October NIST decided that SHA-3 is the new standard hashing algorithm, does this mean we need to stop using SHA-2 as it is not secure? What is this SHA-3 anyway?
0
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0answers
45 views

Detection of pass the hash

I have researched about PTH Attacks but yet found any solid way detecting it in a network.is there a way to detect a pass the hash ? analysing the windows message from the dcs or something ?
1
vote
1answer
95 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 ...
7
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1answer
1k views

Identifying an unknown hash

During some of my research work I encountered an unknown hashed string. What I am curious about is the algorithm used to generate it. A factor that makes it interesting - the string contains an ...
0
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2answers
259 views

Native app, token authentication without login/password

I'm working on a always online mobile game (native android/iOS app with Unity) and i would like to be able to authenticate the player without requiring any login/password at the beginning. For those ...
17
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2answers
2k views

Methods for slowing down a hashing algorithm

I understand why a hashing algorithm should be slow but is the method that makes it slow important to the strength of the hash? Everything I've read says that the algorithm should be computationally ...
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1answer
123 views

What is the right way to implement Keyed Password Hashing?

As mentioned in this wonderful link, the way to get a PBKDF2 Hash of a user given password given a password (of course), a salt (generated Cryptographically Secure Random Number Generator. iteration ...