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 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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3answers
222 views

How to check if your Android app was updated by MitM?

As I was browsing on my phone yesterday, a gray popup appeared on my screen just as I was swiping up, and I accidentally hit the accept button. In the fraction of a second it was on I was able to read ...
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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 ...
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4answers
114k views

Is SHA1 better than md5 only because it generates a hash of 160 bits?

It is well known that SHA1 is recommended more than md5 for hashing since md5 is practically broken as lot of collisions have been found. With the birthday attack, it is possible to get a collision ...
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46 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. ...
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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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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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1answer
87 views

How many hashes do I need to compute to get x collisions?

I know that you need to hash about 2^(N/2) to find a collision taking into account the birthday problem. But I'm not really sure about more than one collision, I mean, collisions with different ...
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8answers
4k views

Won't all hashes collide after enough iterations with a static salt?

We all know that we're supposed to take a fairly slow hashing algorithm, salt the password, and run the hash for many iterations. Let's say that I'm following almost everything except for one rule, ...
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4answers
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Are salted SHA-256/512 hashes still safe if the hashes and their salts are exposed?

Scenario: a database of hashed and and salted passwords, including salts for each password, is stolen by a malicious user. Passwords are 6-10 chars long and chosen by non-technical users. Can this ...
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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....
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1answer
130 views

How can one securely hash passwords server side while avoiding DoS?

It is generally recommended that one use a slow hash function to hash passwords. However, does this create a DoS risk?
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1answer
145 views

Is the 64-bits length of the original string padded as well in the MD5 hashfunction?

So, for example I have a string which binary value is exactly 512 - 64 bits long, so the binary conversion of the string does not have to be padded. So that means I have a string of 56 chars. The ...
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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 ...
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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 ...
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6answers
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Does repeating one word to form a password result in a similar pattern in its encrypted format?

If i use a single word to form a password by repeating it like the examples below: securesecuresecuresecuresecuresecure SeCuReSeCuReSeCuReSeCuReSeCuReSeCuReSeCuRe $eCuRe$eCuRe$eCuRe$...
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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 ...
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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 ...
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0answers
30 views

Change NTLM hash in memory on the lock screen?

Is there a way to change the ntlm hash in memory to bypass Windows login? For example, I have the NTLM hash of a Windows machine and I have physical access. Is possible to write the NTLM hash in ...
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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 ...
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1answer
114 views

What is the difference between a digital signature and whole message encryption?

I am newbie in information security I am trying to understand the difference between a digital signature and encryption of a message. Lets consider simple example of email message. I understand how ...
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1answer
84 views

Is `/dev/urandom` secure to generate a salt on a Virtual Machine?

I've read the new password_hash() function from PHP uses /dev/urandom to generate a secure salt, however this assumes some noise from device drivers. Is possible that /dev/urandom is not so random ...
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Are SHA-2 certificates considered obsolete, or current?

A guide on this site on how to make a decent Certificate Signing Request (CSR) says that I should be using SHA-2 certificates to secure a HTTPS webserver. Are SHA-2 certificates considered obsolete, ...
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Does quick denial tell that you passwords are stored in plain text?

Say you are using a website and incorrectly enter your password. The website then "instantly" pops ups with an "incorrect username/password" message. Would it be safe to infer that the website is ...
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1answer
65 views

Powershell and cached credentials

In my environment we have powershell remoting off- I get around this using 2 hop scripts, packages(exe -no creds are stored in code- local privs only), and iwmi. I never pass creds to the endpoint, ...
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1answer
32 views

Hashing and signing partial data in payload

I'm hashing and signing part of a payload prior to HTTP Posting from a mobile device to server side. The payload contains of about 7 data elements and only 3 of them are hashed/signed using a private ...
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1answer
159 views

How to detect mimikatz usage on LAN

My boss is has made it clear that we need better ways of detecting mimikatz usage on the network- and I would agree. In place already for detection is suricata/ET PRO rule set on a couple of taps. ...
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Is there more to password hashing?

You have a plain text password and salt. The plain text password is assumed to be securely random and only known by the user and the salt is no secret and not necessarily unique but stored alongside ...
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156 views

Best way to hash passwords in PHP 5.3.5

What is the best way to hash passwords in PHP 5.3.5? Since in this version doesn't have password_hash().
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Is the method of hardening the creation of a Cryptographically Generated Address (CGA) called hash extension

CGAs are sha1 hashes truncated to a 59 bit value. Along with a 3 bit security parameter they form a IPv6 address (more precisely the interface identifier). from wikipedia: The Sec parameter ...
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Is it possible to find the salt?

I have this PHP code with me : $auth = md5($username.$password.$salt); I have a dummy value : $username = user $password = password And I also have the resulting MD5 Hash : ...
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4answers
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Why shouldn't I store passwords in plaintext? [closed]

Why is it so important not to save passwords in plaintext? I think it is the same issue like authorizing a user on a RESTful webservice, where most developers claim: "Don't send your security token ...
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when to use encoding over hashing?

If encoding is used for integrity someone can tamper it across the network because it is based on some publicly known scheme. When do you use encoding and when do you use hashing for preserving the ...
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5answers
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How does storing hash passwords work? [duplicate]

In usual network applications, that employ password hashing, is the user password hashed on client side before sending it to the server, or is it sent without hashing as encryption of plain text ...
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9answers
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Why improvising your own Hash function out of existing hash functions is so bad

I'm afraid I'll have tomatoes thrown at me for asking this old question, but here goes. After reading that cooking up your own password hash out of existing hashing functions is dangerous over and ...
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1answer
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Passing a hash of a secret to a server instead of the plain text

Instead of passing an authentication token or api key in an http header to a server in the plain text, what if I calculated its hash and passed the hash? This way even if a adversary intercepts the ...
5
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1answer
133 views

Reviews of Argon2

I am not a security guy but just curious about the things here. I have seen several people in various answers here talked about the password hashing competition. Now that the winner is announced, I ...
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2answers
99 views

Idea for an encrypted pastebin NON-web application

I have an idea for an app that might be useful (though if it isn't, I've still learned in the process, which is what matters). There are a bunch of encrypted pastebin web apps out there (e.g. defuse....
40
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6answers
17k views

https security - should password be hashed server-side or client-side?

I am building a web application which requires users to login. All communication goes through https. I am using bcrypt to hash passwords. I am facing a dilemma - I used to think it is safer to make a ...
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2answers
54 views

Incrementing Work-Factor of Hash Functions Over Time

For a long time hash functions have required a work-factor in order to keep the operation "slow" enough to protect individual passwords in the case of a database leak. Bcrypt and PBKDF2 being notable ...
3
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1answer
117 views

Two-phase anonymization

EDIT: [N.B: I fully replaced the original question which was not a very good statement of the problem (see comments) with a more apt one.] I have records that contain - among other things - the ...
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2answers
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Upgrading security of hashed passwords [duplicate]

Let's say we have a database with usernames and passwords, where the passwords are naively secured using a single round of SHA-1 (such as was kinda best practice a number of years ago). Now, let's ...
3
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What scenario are 'extra' strong passwords and hashing algorithms actually protecting against?

Note: I completely understand the need for strong passwords & I understand that there is an issue of speed with hashing. I am just interested in better understanding the actual negative impact of ...
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30 views

The optimal settings of Winrtgen GIU

I'm working with Winrtgen GIU on windows, but I can't fix the right settings to create a rainbow table for a: password length=1-7 Charset=alpha numeric all space What are the ideal values to put in ...
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4answers
148 views

Is knowing the salt a problem?

I understand that adding a salt would thwart the use of rainbow tables. I don't understand the time it would take to create a rainbow table for a certain salt and of course this is dependent on the ...
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1answer
63 views

Is appending plaintext to salt equally safe as appending salt to plaintext

Is using hash(salt, plaintext) equally secure as using hash(plaintext, salt), i.e. can the plain text be appended to salt in place of appending salt to the plain text. Why or Why not? What kind of ...