Tagged Questions

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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2
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0answers
26 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 ...
0
votes
2answers
68 views

Are there any good tools to test the encryption quality of data?

I am trying to increase my understanding of data encryption, and I was wondering this. It would be really nice if there were any good tools to test how secure my encrypted data is, for example how ...
1
vote
1answer
55 views

Perfectly Robust Hashing Scheme, or Completely Over-Engineered?

This is going to get long, so prepare. Basis of the question is, Do all these steps improve security, or am I completely overthinking the problem? Are my assumptions/thought process valid? We all ...
0
votes
2answers
43 views

What is the solution for handling exceptions in password hashing schemes?

There is a technique called password hashing that describes creating unique passwords based on a unique master key and a static and arbitrary hash value. Using this technique, the user only has to ...
-3
votes
0answers
38 views

What encryption or hashing algorithm is likely to be used here? [on hold]

I want to use the USERS table of a proprietary 3-rd party tool for user authentication. The column PASSWORD is of type VARCHAR(35). It holds the following data: 64783641124722847161648230000000000 ...
-4
votes
1answer
48 views

How does https check md5, sha-1 and sha-2 fingerprints?

When a https site shows multiple finger prints, i.e.: md5 and sha1, or sha256 and sha1, how does the browser check? is it both just the "strongest" or whatever is convenient? This question arose ...
31
votes
8answers
6k views

Do bad passwords produce bad salted hashes?

When you have a password stored in a database that has been strongly hashed and salted does it really matter if the underlying user password is weak? If you setup features like limiting login ...
0
votes
1answer
26 views

XOR-Cascade of weak hash secure?

I have following theoretical question: Let H(X) be a hash function which is considered as weak because collissions can be produced (e.g. SHA1, MD5). I wonder if following functions: H2(X) = H(H(X)) ...
3
votes
1answer
73 views

How to best to secure data over HTTPS

My aim is to have an (iOS) app in which the user would login, then on sucsessful login, gain access to additional information over an encrypted webservice (undecided). From research, I understanding ...
8
votes
5answers
1k views

Should I remotely store my salt? [duplicate]

When users register on my site, I want to store their username and hashed password in my database. When I hash that password, I'm going to salt it using PHP. The issue is, I don't want to store the ...
0
votes
3answers
55 views

How SplashData knows about Worst Passwords used by users annually

It is known that every reputable website stores their user passwords into their database after implementing some hashing algorithm on it, and even they don't know what the actual password of the user ...
0
votes
1answer
93 views

Identify an unknown type of hash [closed]

I've come across an unknown type of hash value which looks like this: AAAAAATOM2KIII+kbR/Dqw3TLTw4PHsGPZft2c+b93rImFIuAQ== The corresponding hex string is: ...
1
vote
1answer
39 views

truncated hash for message authentication?

I am using hash for authenticating the signature of the message. since the hash will be part of a url that is used for QR code, I would like to keep the hash as short as possible in order to generate ...
2
votes
0answers
24 views

HMAC implementation failure [migrated]

I hope this is the right forum; I was not sure if I should ask this in stackoverflow, cryptography or security. So my problem is that php's hash_hmac function is only available with php >=5.1.2. ...
-2
votes
1answer
85 views

What is “Pass the hash” attack?

The article on Wikipedia doesn't explain how the attacker can authenticate to the remote server using the hash instead of the original password. According to the following article the attack is still ...
3
votes
2answers
235 views

Is it unsafe to have hashes of parts of a private string

We have string B and the hashes hash(P+B), hash(P); is it possible for P to be revealed easier using this information than having hash(P) ? What is the difference ? Any links to articles or any ...
1
vote
2answers
113 views

Is it a good idea to use the user's username as a salt when hashing a password like hash(username_str + password_str)?

I'm helping my friend with hashing his passwords, and I've a question - Should he use one secret string as salt for hashing or is it better to have each user its own salt for hashing? Consider these ...
-2
votes
3answers
105 views

My friend hashes passwords with SHA512 algorithm without salt. How do I convince him that he needs to add salt?

Today I discovered something incredibly stupid - my friend hashes user passwords with sha512 algorithm without a salt. I immediately raised this issue to him but he said he wants to see anyone crack a ...
2
votes
2answers
71 views

Difference between Second Pre-image Resistance and Collision Resistance in Cryptographic Hash Functions

I am studying the subject from these notes. However it is not clear what is the difference between "Second Pre-image Resistance" and "Collision Resistance" properties of Cryptographic Hash Functions. ...
2
votes
1answer
60 views

Security of shared “super pin” code table at meineschufa.de

The german brank credit report service "Schufa" uses a so called "SuperPIN" to enable users to reset their password. This super pin is a permutation of 30 lower and upper case letters and digits and ...
1
vote
0answers
96 views

Breaking it gently

Let's say I've found a fundamental error with mathematics of a security package. For example, let's say I've found something similar to the Pollard’s \rho-1 algorithm that renders some of the RSA keys ...
0
votes
0answers
53 views

/etc/shadow in old format, where is salt stored? [migrated]

In /etc/shadow I have entries such as admin:YtChlvAGYzva2:16318:0:99999:7:::. I know the original password and would like to generate the same hash somehow. However, running openssl passwd -crypt ...
-3
votes
0answers
50 views

Why does sha1 return a different hash for the same input string? [migrated]

This is a very simple program that takes a integer and converts it to a string. From there I hash the string using SHA1 and print the hash to the console. But when I rerun the program, I get a ...
3
votes
1answer
125 views

Windows system password hashed - see which hash is used

How can I know / see if my windows is using NTML, LM, NTML2 for its user account passwords? What is the standard today, in windows systems?
1
vote
1answer
63 views

Can a known MD5 hash limit the search space for SHA1 collisions?

For a course in game theory, we are dealing with BitTorrent and alternative strategies (roughly alternative clients) we can employ to maximize our download speed. One strategy is to over-report the ...
0
votes
0answers
147 views

John the Ripper - Calculating brute force time to crack password

I'm using incremental mode (brute force) mode in John the Ripper to crack Linux MD5 passwords. I'm trying to calculate the time it will take to run through all combinations of 12 passwords (with 12 ...
3
votes
3answers
475 views

Accepting other similar passwords when storing a salted, hashed password

If a website stores passwords as a salted hash, is it reasonable to accept similar passwords as correct? For example, given the password stackexchange, does it dramatically decrease security if the ...
7
votes
2answers
387 views

Does Outlook store plain-text passwords?

A long time ago when Microsoft changed my e-Mail from Hotmail to Outlook the password-interface said that I should only put in the first 16 chars of my password. But my password was longer before. So ...
1
vote
1answer
83 views

Adding hash value to user supplied URL in a web application: any security benefit?

We administer a Java web application from an external supplier where we have access to the source code. The user is able to provide an external URL which is stored in a database and later on embedded ...
4
votes
0answers
82 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. ...
0
votes
1answer
92 views

How to decode/decrypt strings of text [closed]

So I'm trying to decrypt/decode some text strings. I don't believe they're hashes because they vary in length too much and the software they are used for is able to easily decode them and display them ...
0
votes
3answers
96 views

Is is necessary to encrypt the message digest?

In symmetric key settings, in order to provide the message integrity, we compute the hash of the message. The message along with the message digest is then encrypted. Is it necessary to encrypt the ...
10
votes
2answers
141 views

How safe are signed git tags? Only as safe as SHA-1 or somehow safer?

How safe are signed git tags? Especially because git uses SHA-1. There is contradictory information around. So if one verifies a git tag (git tag -v tagname), then checksouts the tag, and checks that ...
-1
votes
1answer
144 views

How do I hash a password in C#? [duplicate]

I assume that the best way to handle passwords for a website is I create a hash of the password and save that hash in my database. Then when someone tries to login, I do a hash of the password they ...
1
vote
2answers
121 views

Search on hashed data

We have a request to encrypt customer personal data (e-mail, address etc.) We use MySQL which does not have any TDE like MS SQL or Oracle. So along with encrypting data we need to preserve ...
2
votes
3answers
121 views

Is it ever safe to publish hashed data?

I'm having a friendly debate with someone who thinks that a website can safely make public sensitive data about it's users as long as that data is hashed (don't ask why, it's a long and hypothetical ...
0
votes
2answers
38 views

Protect against malicious client with key derivation function (PBKDF2)?

Consider a protocol that allows clients to retrieve XML "forms" from a server. Forms are identified by a unique, randomly generated form ID that is embedded in the form. Clients fill out the form and ...
0
votes
3answers
362 views

What are the differences between dictionary attack and brute force attack?

Can someone explain the major differences between a Brute force attack and a Dictionary attack. Does the term rainbow table has any relation with these?
0
votes
1answer
72 views

Secure log in without sending plain test to server

I know this question asked so many times, but here I am again with it. I am working on an application in which I need to log-in users but the question is it is not a good Idea to send user credentials ...
3
votes
2answers
166 views

Is there a strong reason to salt and hash passwords when password reuse is not an issue?

I am dealing with a system (in development) that uses randomly generated (not user provided), unique, strings to authenticate services that will consuming an API. Right now, these strings are stored ...
7
votes
4answers
985 views

Why secure encrypted data consistency by strong hashing?

Consider the SSH protocol: the SSH packet is like [data, SHA1(data)]. The packet is entirely encrypted by a block cipher. The question is, why do we need a strong hash to protect the packet ...
2
votes
2answers
127 views

How safe is to secure sensitive content by URL with MD5 hash and no other authorization?

Suppose we have website that use MD5 hash in URL like this: http://somewebsite.com/XXX/ where XXX is MD5 hash. Content of this website may have sensitive information like transaction details with ...
13
votes
3answers
1k views

Trying to understand why signatures in root certs “are not used”?

Taken from here: Don't worry if the root certificate uses SHA1; signatures on roots are not used (and Chrome won't warn about them. Why are the signatures not used? Are not root certificates ...
0
votes
2answers
65 views

Is my Password Hashing Secure or not?

I have recently created a code for hashing password. Can you please give your advice over the security of my code? The function takes a password, then converts it to a number. #include <string> ...
4
votes
1answer
117 views

Using random number to salt passwords

in a project I have, I'm salting passwords with 3 salts at the moment... Static salt - hard-coded into the source-code. Randomly generated salt (using a function designed for generating password ...
0
votes
1answer
85 views

Idea for an algorithm to authenticate users with zero-knowledge-proof [need thoughts/review]

I have an idea for an algorithm. I don't know if I made any mistakes and need some extra thoughts/peer review on it. This would work as an (almost)zero knowledge proof for sending passwords that can ...
0
votes
0answers
20 views

Is there any way possible that a Digital certificate is issued by admin on wireless channel?

I want that an admin who is working in a wireless environment have to issue digital certificate to the node, who wants to register itself with the network. this certificate will be used by user to ...
0
votes
2answers
61 views

Authenticate User Salted Hash Without Username

I've got a page with a login system where you type your username and password, the salted hash gets pulled down from the database depending on the username ... SELECT hash FROM db WHERE username = ? ...
0
votes
1answer
84 views

Why is the brute force search time for hashing algorithms 2^(num_bits / 2)?

I noticed that the brute force times (the time it takes to find a message that hashes to a given hash) of various hashing algorithms seems to be 2^(num_bits / 2). For example, people say that brute ...
1
vote
1answer
99 views

HMAC secret key for securing communication - how to keep private on DB

I have a mobile app that communicates to server over HTTPS. To authenticate the client and to make sure its who I believe it is, I return upon successful signup (apart from the username) a secret API ...