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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316 views

Brute Forcing LUKS Full Disk Encryption - Time?

let's say we have encrypted our drive with AES 256 XTS and the following Hash: SHA1 with ~500k Iterations and a 20+ password SHA512 with ~250k Iterations and the same 20+ password. Let's think of ...
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2answers
122 views

About SHA1 in default Disk Encryption in Linux

Link to the Thread: Recommended options for LUKS (cryptsetup) I wonder what's the exact difference between SHA1 and SHA512. I know that SHA512 has a longer key but I've read that it doesn't matter ...
3
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5answers
356 views

Are all unsalted password hashes inherently insecure?

Maybe I'm missing something obvious... Are all passwords stored in common, unsalted hash algorithms able to be attacked via rainbow tables?
2
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1answer
183 views

PBKDF2 strong salt for client-side hashing

What should I use as a secure/strong salt for PBKDF2 hashing when salt is not available to use before login as it will be client-side javascript to hash user+pass with PBKDF2 ? I'm going to use ...
1
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1answer
71 views

PBKDF2 strong salt

I want to use a strong authentication scheme, so I decided to use PBKDF2. I'm using PBKDF2 with SHA256 algorithm, 5000 iterations and I use username (which is full email address of user) as salt. So ...
0
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3answers
236 views

Testing a password for similarity to previous hashes

This question is a follow-up to a comment by Tobias Kienzler to an answer to "What is the purpose of the “Password minimum age” setting?". Consider a password policy that new passwords cannot be ...
6
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1answer
285 views

Any problems with scrypt yet?

In the question Do any security experts recommend bcrypt for password storage? Thomas Pornin recommends the hashing function scrypt but saying it is "too new to be recommended on a general basis". ...
3
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3answers
272 views

Are credit card number look ups more secure with a hash function than with a deterministic encryption algorithm?

I understand PCI DSS 3.0 allows hashes of cardnumbers to be stored separately from encrypted values, but I'm startled at the efficiency of tools like hashcat in discovering card numbers from hashed ...
5
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2answers
134 views

which memory hard hashing algorithm can equalize low-computational and high-computational power devices to utilize blockchain in the IoT?

Recently IBM and Microsoft showed their interest (IBM post, Microsoft post) in utilizing bitcoin's blockchain for internet of things (IoT) development. Let's assume that in close future the blockchain ...
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1answer
71 views

Storing salt and hashed password [duplicate]

Is there a benefit to storing salt appended to hashed password in a single column of a table verses storing salt and hashed password in different columns of the table. The OWASP guide here ...
0
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0answers
73 views

How much risk is introduced by git's signing the commit hash rather than the blobs? [duplicate]

Since first switching from centralized VCS systems to a decentralized one—specifically git—I have properly understood that that git's commit ID's were hashes of the included objects and some meta data ...
0
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1answer
129 views

How to secure sensitive data in application with message queue

Currently we are creating one small service, where we are using some sensitive data from users(not worth zillions but to me it is like password). The idea is that application itself only inserts this ...
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votes
2answers
59 views

Can I prevent brute forcing of hashed+salted user passwords without a dedicated validation server? [duplicate]

Salted hashes don't seem to offer any real protection for user passwords by itself. So long as a hacker has a quick way to check if a password is right or wrong, it's trivial to brute force it to view ...
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2answers
59 views

One-way function for data synchronisation

I have to synchronise small sets of data between two or more systems over an insecure network. First I have to check that the other system has the same unique identification information for the data ...
11
votes
2answers
937 views

How can I find out the password hashing schemes used by the specific Unix accounts I log in to?

Every day I ssh in to 3 or 4 independent Unix accounts. I have been regarding them as more or less "equivalently secure" on the grounds that I'm using ssh, but after learning of how much variety ...
0
votes
2answers
76 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 ...
0
votes
3answers
968 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", ...
3
votes
2answers
145 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 ...
0
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1answer
390 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 ...
0
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0answers
23 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 ...
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1answer
96 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: ...
3
votes
5answers
282 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 ...
0
votes
1answer
95 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 ...
0
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1answer
133 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 ...
0
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2answers
108 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. ...
4
votes
2answers
80 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 ...
11
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1answer
654 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 ...
2
votes
1answer
290 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, ...
2
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0answers
69 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 ...
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0answers
134 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) ...
2
votes
2answers
541 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 ...
0
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1answer
288 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? ...
0
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1answer
110 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 ...
2
votes
1answer
879 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
205 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 ...
23
votes
4answers
5k 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, ...
2
votes
3answers
195 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 ...
0
votes
1answer
114 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 ...
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votes
1answer
110 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 ...
0
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0answers
63 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 ?
6
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7answers
4k views

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 ...
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 ...
1
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1answer
391 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 ...
20
votes
5answers
4k views

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 ...
5
votes
3answers
386 views

Are there any disadvantages to encrypting the password hash?

Is encrypting the password hash in database more secure than storing only the hash? Suppose we store encrypted SHA-256 result with AES instead of hash directly. Is this a good protection from a ...
1
vote
1answer
94 views

Using salt or secret for Hmac

I'm working on a web API. We are going to use Hmac256 for signature hashing. From what I can gather, the secret is a key used to initialize the hash algorithm (ie to generate a random number). The ...
1
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1answer
164 views

How are SHA1 and MD5 considered to not protect against collisions?

SHA1 and MD5 hash functions are considered to not protect against collisions while SHA2 is. Is it the size of the message digest that makes this or the algorithm itself? If it is based on the message ...
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2answers
120 views

bscrypt,scrypt v/s iterative SHA-x [duplicate]

Both bcrypt and scrypt hashing algorithms are designed to increase the resources required during the computation. Hashing passwords with these algorithms can be beneficial as it makes the task of an ...
3
votes
1answer
82 views

Feeding PBKDF2 to SRP verifier creation

There is an older game that solely uses UDP to communicate, and I wanted to add password authentication to the game to facilitate things like experience points and rankings. To this end, I decided to ...
2
votes
3answers
469 views

Can password_verify() be used to identify password after database breach?

I am a newbie to PHP and password hashing. I am following the instructions provided here to hash my user password before storing. My questions are: PHP recommends password_hash() method as a ...