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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How secure are hashed passwords that are salted too?

SAP Netweaver has its passwords hashed and also salted. But I read that a tool such as John the Ripper can bruteforce them. So how does security varies when passwords are hashed, in particular in the ...
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2answers
367 views

Does using Bcrypt to encrypt credit card numbers satisfy PCI compliance?

I understand that using MD5 is not safe and is not PCI compliant. Does using BCrypt satisfy PCI compliance
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1answer
199 views

The Hash header in GPG ASCII armor

When sending a signed message using GPG, it always includes a line that says Hash: SHA256 right at the top of my email. I was wondering if/why it's required, and if not, how I can remove it (in an ...
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2answers
718 views

Finding out whether a website uses unsalted MD5 for password hashing

I'm working on a project where websites are analyzed and rated according to password security (factors like min/max password length, alphabet size and more are then calculated into a score). A great ...
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2answers
814 views

how to know what hash function have been used

I have a hashed password and the plaintext password and i want to know the exact algorithm that's been used. I have the input and the output of the hash/encription algorithm. How would I know what ...
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1answer
156 views

Securing communication

The problem: I have an open-source client (a Firefox add-on written in JavaScript) and a server containing somewhat sensible user information: username and user history (all from YouTube). The client ...
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1answer
56 views

Is bcrypt suitable for modern use? [duplicate]

When the subject of password hashing comes up, a lot of developers get exasperated by people using outdated, broken, or hand-rolled hashing schemes, and I frequently hear "just use bcrypt!" repeated ...
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1answer
72 views
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1answer
116 views

Is it possible to insert data into UUID?

Is it possible to insert arbitrary data into UUID? Let's suppose we have an MD5\SHA hash of something... can we encode that data into a valid UUID?
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2answers
113 views

Any reason to use bcrypt, pbkdf2, scrpt for other things than passwords? [closed]

Let's say I want to hash some data, using SHA256, in order to prove I know something. Maybe it's my secret ID for something. In the real of passwords we have moved from hashing -> hashing+salt -> cpu ...
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2answers
83 views

Password stretching using concatenation of hashes

I'm working on a simple file encryption tool. Basically, here's how my program works: password = get_user_typed_password() salt = uuid4() key = bcrypt(password + salt) cipher = AES(key) for block ...
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2answers
311 views

What is the advantage of using a symmetric cipher like AES to generate a keystream?

I see examples of AES (with a shared secret key) being used to encrypt shared secrets (e.g. nonce + counter) to produce a keystream against which the plaintext is XOR'ed to produce the ciphertext. ...
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2answers
169 views

scrypt strength with “weak” salt

I'm working on a project where following constrains apply: There's no remote database or any other means of storing extra data like random salt When user logins in, only username and password are ...
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1answer
216 views

What does it mean by the 'Hash of a malware'?

I have just recently started to delve into the topics of malware. In my hunt for malware binaries, I came across certain responses that it is not easy to grab binaries based on malware names like ...
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3answers
485 views

DNS queries with hex string that is a SHA1 of a domain name! Is it a malware?

My computer does a lot of queries to strange domains such as: 56cea5c2b408989ab067adcb787d0f99209bbe07.mydomain.com The strange thing is that 56cea5c2b408989ab067adcb787d0f99209bbe07 is the SHA1 of ...
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1answer
45 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 ...
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1answer
62 views

Cryptographic Hash function [closed]

How can I implement a cryptographic hash function using the block cipher? I was wondering whether I can use AES in cipher block chaining mode to achieve this.
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1answer
72 views

Is using MD5 in NTLMv2 protocol to store Windows passwords is secure?

I read that Windows (probably not new OSs but say, Windows Server 2008) stores passwords using Hashes using NTLMv2 protocol which uses MD5 hash function. My questions: MD5 is known to be insecure ...
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1answer
56 views

What kind of encoding/hash it is [closed]

I have email which is stored in Cookie : %2FGl%F8%7E%06%F1S%FEF%10%E0T%B3%95%82BK%D9%D3%94%BC%AE%E1 which is sth like this after convert it with this tool : ...
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1answer
45 views

Verify external data files for an application

I have a C++ application with an algorithm, whose usage I want to protect. The application needs several input data files to work (those may change for each client). My goal is to allow only ...
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1answer
57 views

Review of approach to client-side only hashing and encryption for web application

Background: I have little knowledge of hashing and encryption, so please bear with me. I have posted a related question here: ...
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1answer
92 views

Hash user id securely

In my app I'm using Facebook login and creating a local user in my DB after retrieving the data. When saving the Facebook ID in the DB I need to hash it, as I don't want the ID to be in clear text if ...
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1answer
50 views

Storing third party auth info; Is this secure?

I have a feature request to connect my PHP web-app to the users mail server. I have usually strayed away from this type of work as it will mean storing the users email passwords. My question: is it ...
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1answer
57 views

Breaking encryption with hash value of password?

Can you break an encrypted volume if you know the source code of the crypto-tool used and the hash value of the secret passphrase? Why is it not possible to just reverse engineer the passphrase ...
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1answer
145 views

Hash the signing key of an authentication token in database

I have clients which are all browsers. All clients render just a single page application getting data from a Web API. The design of the API follows REST principles. I use token-based authentication ...
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1answer
104 views

Is a simple Whirlpool hash with random salt secure enough? [duplicate]

I've been working on a site that requires users to login. It's written in PHP with MySQL, and passwords are stored as Whirlpool hashes with a salt (source code later). However, security sites or ...
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1answer
108 views

Is it a good idea to hash a string and use it as a passphrase?

Is it a good idea to hash(SHA-512/whirlpool) some simple memorable string and use it for passphrase(for LUKS/TrueCrypt container), instead of using just a string like t4k#La93Fs(5w5) as a passphrase?
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1answer
68 views

Payload authentication + HW-SW Binding

I want to authenticate a (2nd stage) bootloader during the boot process using a symmetric key, which is derived from HW properties of the platform the bootloader is running on. Thus, I want to bind ...
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2answers
123 views

Would multiple exposed bcrypt hashes of the same UUID v4 with random generated salt be too insecure?

I'm looking into implementing an ownership check on JSON objects and want to avoid going back to the database to ensure ownership of said object/record (i.e., to prevent a user from updating an ...
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2answers
284 views

Algorithm to generate NTLMv2 Hash in PHP

I am trying to develop a PHP function to calculate NTLMv2 hash by providing server & client challenge, domain, account and password. The resulting hash appears to be not correct. Can someone ...
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1answer
1k views

John the ripper passwd file format with salt not working

I'm trying test password strength in one of our e-commerce sites. I'm using john the ripper to brute-force a password file. The algorithm used by PHP is: $hash = md5($salt . $pass) No other ...
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1answer
476 views

How do I generate a blowfish password hash in Ubuntu?

What's the command line to generate a blowfish password hash? I can't seem to figure this out at all. Apache's htpasswd only supports bcrypt, and openssl passwd doesn't even do blowfish hahes (but it ...
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4answers
137 views

multiple hash values in a single malware file

Can a malware file have multiple "Hash values"?
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2answers
690 views

How can I extract the MD5 hash of a password protected MS Office Word 2000 document?

AFAIK, the compound file format identifier is D0 CF 11 E0 A1 B1 1A E1, which is located in the offset 0 of the header, which has a length of exactly 512 bytes. However that is not enough to get the ...
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0answers
7 views

What can I change in Lane to [migrated]

What can I change in Lane to increase memory (and compute) consumption. My first idea would be to change n, but with Lane hash function is there a way I can up the n to a level higher than 512. If I ...
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0answers
21 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 ...
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0answers
59 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
45 views

How does an attacker authenticate to a service using just the hash of the user (after performing a pth attack)

Let's say the attacker got the username and the password's hash. How can he use it when authenticating to some service in its domain with NTLM , for example? How can he send the request as the ...
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1answer
116 views

Windows 7 password recovery [duplicate]

A few weeks ago I've changed the password on my old laptop, I forgot the password as I wasn't using it often. Now I need to recover the password because I used it to encrypt some important documents. ...
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1answer
125 views

Rainbowtable - Start with plain text [duplicate]

I know how to use rainbow tables. I've already read the other questions this topic here. Well but there is still one question left. As an attacker, I usually have a hash value of a password and ...
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0answers
51 views

Does the ordering of encryption and hashing matter? [duplicate]

I am now learning keyed hash function, where A and B share a secret key k. I want to know if the ordering of encryption E and hashing H matters? i.e. Is there any difference between H ◦ Ek (m) and Ek ...
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3answers
191 views

Need references about why public access to a password hash and salt is poor practice

What are some published industry standards about why revealing the password hash and salt are poor or bad practices from a security perspective? I am dealing with a vulnerability where anyone can ...
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0answers
31 views

How can I determine the encryption used by knowing input and result? [duplicate]

Is it possible to determine the encryption or hash used if I know the original input and final output? There is a similar post here: Determine encoding/hashing methods used based on knowing the input ...
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1answer
56 views

Using multiple hash-functions along the line [duplicate]

I was wondering what the effect on strength/security is If I would use an aggregate of multiple hash-functions. For instance, I don't want to sent passwords in plain text (although it's over an ...
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votes
3answers
181 views

Salting in encryption (rather than hashing)

I am aware of the benefits of adding a salt to values that are hashed using a one-way function. Is adding a salt to a value that is being encrypted (using symmetric encryption) considered to be good ...
-1
votes
1answer
126 views

Is my hashing technique secure? [duplicate]

I am not sure if this is the best place to post this type of question. I have come up with function which, I believe, is a very secure method of hashing. (I could be completely wrong). Here's the ...
-1
votes
1answer
90 views

Password sending through network [duplicate]

In case of no TLS/SSL available, why can't I use the hash of the password (SHA512) as the key to encrypt the password (with out any salt) to send through the network ? MITM attacks I can understand, ...
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votes
1answer
188 views

After salting my passwords, are they protected against dictionary attacks? [duplicate]

I use sha1() to hash my users passwords, but recently a friend told me that if someone get the hash then they could use dictionary attack and he recommended using salts. I implemented a random salt ...
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3answers
109 views

Secure transmission for desktop applications

Suppose I have a desktop application that does password hashing for login authentication. Is the password normally hashed before it travels to the wires or does it travel to the wires first in plain ...
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2answers
2k views

How to get an NT hash from registry? [closed]

I want to manually get the NT hash from the registry (without any tool). Let's say just for the administrator. I know that it must be stored in the SAM area of the registry somewhere so I tried to ...