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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Is encryption with a destroyed key a good cryptographic hash function? [duplicate]

Obviously this isn't something I was going to implement, but it was a question floating at the back of my mind. So let's say that instead of hashing passwords to store in the database, you encrypt ...
20
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6answers
5k views

What is a good practical (and sane) way to manage all your passwords for online sites?

I am just a mere mortal that wants to have a somewhat secure way of managing all my passwords. This is something that I have been putting off, but since LinkedIn decided to give away one of my ...
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2answers
142 views

How to securely transfer password from a registration page to the database [duplicate]

What steps must be followed to send password securely from the user registration page (i.e. client side) to the server over a non encrypted channel (http) when the user registers for the first time ...
4
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2answers
156 views

Location of Password Hashes on a Windows Local Machine?

"Where are the two locations that user's password hashes are stored on a local windows machine?" My place of business asked me this question. I know that the SAM stores password hashes, where would ...
13
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2answers
362 views

Can client-side hashing improve after-the-fact security in response to password leaks?

Several questions on this site address client-side password hashing, and none of them admit to any security benefit beyond protecting other sites the user might use the same password for. However, ...
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2answers
174 views

What is is the best way to create virus signature database? [closed]

We are thinking to develop a new Antivirus program. The main concern is to create a virus signature database. I want to ask what is the best possible way to add viruses signature in our database to ...
27
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10answers
5k views

Could I recover the content of file from its checksum/hash?

Let's say I have a video file that is split into multiple parts. Each piece is 2 Megabytes. I also have a list of the *insert hash name here* for each piece and also for the full file. Now assume ...
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0answers
39 views

Transmitted sensitive user data

At the moment, I have set up mitmproxy and can record all HTTP/HTTPS communications between the client and server. For research purposes I am looking to find a way to detect potential leakage of ...
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2answers
103 views

Is there a threshold of bits of entropy below which hashing becomes meaningless?

I just read a help page by a mail provider in which they state that all mobile phone numbers will be stored as a salted hash. This strikes me as interesting, since phone numbers don't contain a lot ...
2
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3answers
98 views

Verify password hashed with nonce when the password is already hashed on the server?

I found this picture in the Wikipedia nonce article: To avoid sending the password in clear text and prevent replay attacks, the password is hashed together with one random number from the server ...
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3answers
147 views

why not use hashed password as password [duplicate]

Why dont we use our mobile phone tho hash a password and then enter the hash on a website as the password ? This way the password for the website would be much more complex. Would this even increase ...
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1answer
80 views

Protecting email addresses if their hashes are publicly avaliable

I am working on a project, where user email address hashes will be available publicly, and I need to prevent them from being quickly discovered by spammers. The main idea of the undertaking is to ...
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5answers
9k views

inquiry about SHA1 with RSA for certificate signature

As you all know, plenty of X.509 Certificates use (PKCS#1 SHA1 with RSA encryption) as the Certificate Signature Algorithm for generating the signature of 2048 Bits long. We know that SHA1 hash ...
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3answers
78 views

how to know the way in which password was encrypted [closed]

i have a encrypted password basically hashed i don't know what it is some thing like 11dfb34b27f539a5e785b68e529fd470 and i know the password i.e., the plain text but i want to know the way that how ...
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2answers
88 views

Isn't oAuth weaker than traditional passwords

I understand the need for oauth for programmatic access to apis, etc. whereas passwords are used for more human-level authentication. However when we store passwords, we (hopefully) salt + hash them. ...
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2answers
61 views

PGP vs Hash functions

What is the difference (in terms of security strength) between checking a package' integrity using pgp and hashing functions (i.e. sha256)? Isn't pgp less secure as the verifier must trust the ...
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1answer
54 views

What reasons for implementing reversibly encrypted data are there? [closed]

Excuse me if I am wrong, as I am very new to the field, but it seems that the only reason one should encrypt something in a reversible way is if the object receiving the encrypted data is a person. ...
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2answers
101 views

Using a hash to encrypt data

Lately, I've been reading about cryptography and thought of a method of using hashes to encrypt data. From what I know, hashes are unique to each object and are one way functions. Encryption on the ...
42
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12answers
10k views

Is there any real value in hashing/salting passwords?

I look after a system which holds a lot of "low grade" information, nothing financial but name/address/email etc. Someone has suggested that we up the security from the current in house password ...
1
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1answer
74 views

Re-sign Certificate Using Different Hashing Algorithm

Consider a certificate used by a Certification Authority. This is currently hashed using SHA-1. I'd like to keep the same public/private key for this, but hash it using SHA-256. By hash it I mean hash ...
6
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1answer
298 views

Who in UK I can report to if I know company is storing my password in plain text?

I live in UK, some time ago I wanted to login to my electric company account to check the bill and such, and I had forgotten my password - long story short I got my account locked and had to call ...
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3answers
42 views

Why are there Hashes next to downloads? [duplicate]

I've seen several sites wehre they would put the hash of the downloadable file next to the file. Why do they do this ? I understand the purpose of comparing the hash of your file with the online hash ...
3
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2answers
116 views

Are there any known MD5 hash collisions of messages of different length?

All the examples of MD5 hash collisions I've come across comprise two different messages (inputs) of the same length. The first and second messages have different values for a number of bits and the ...
3
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1answer
446 views

Using MySQL 'encrypt' / crypt() to store passwords?

I've been tasked with deploying a FTP instance with a MySQL backend for storing user logins. Looking online I found Pure-FTPD, which on paper is great. However documentation states it only allows ...
2
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2answers
89 views

What does it mean to have authentication without confidentiality or authentication without encryption?

I came across these functions m+EeA(H(m)) (for authentication without confidentiality) and m+H(m+k) (for authentication without encryption) and I'm having a bit of a difficult time understanding them. ...
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1answer
197 views

How to brute-force WPA-2 password of specific set of characters using oclHashcat?

I want to test oclHashcat on a WPA-2 PSK password of length 8 containing only characters in the set {a-z, A-Z, 0-9}. To do this I have already captured the handshake in a .cap file and converted it ...
4
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3answers
996 views

Determine hashing algorithm only with known input and output

Given the input: test A system generates the following output hash: 0x001F41B6A0534D3B851D69EFE6237F550100000010D5F4FC65E64BCFDBF2590212E4411C44942C6C734C00ACFE13B958DCAB3614 I do not know ...
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3answers
147 views

Hash algorithm that provides less than 10 bytes

I know it's insecure, but I need to for number of profile; I need a hash algorithm to provide less than 10 bytes.
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0answers
36 views

Applocker rules Publisher vs hash

I'm interested in deploying application white-listing for a large scale environment by using the Windows Server built-in AppLocker mechanism. There is no Internet connection to the environment. My ...
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1answer
115 views

insecure hash functions

Good hash function should be collision resistant. In 2004 it was shown that MD5 is not collision resistant. As such, MD5 is not suitable for applications like SSL certificates or digital signatures ...
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2answers
119 views

What is the real advantage of using a “more secure” algorithm like bcrypt for password hashing?

I read this article about password hashing using bcrypt as the recommended method. The advice is similar to what they're saying on hacker news about not using something like SHA2+salt. There are other ...
0
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0answers
38 views

Hash function for credit card [duplicate]

Hey PCI and hash expert, What hash function is good for hashing credit card and providing collision resistance? Some context: We are building a tokenization service, so each credit card will have ...
0
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1answer
46 views

Unique human view count system without captcha on Pay Per click system, using cryptographic proof of work

I have a system that will be paying users per unique view on a page. I need to prevent 80% of fraudulent automated traffic from being counted. I need to avoid captcha.I would like to implement a ...
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0answers
59 views

SHA1 and SHA256 initial digest to start from

Let's say I have: C = A + B where A and B contain strings and the plus sign means concatenation. I already hashed A with SHA1 and SHA256 and got a digests. I forget what the original A string was, but ...
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1answer
130 views

Yii client side captcha validation

Apparently, Yii web application framework generates some kind of hash value from captcha codes it generates and sends it to the client side so it can be used for client side validation of the captcha ...
3
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2answers
86 views

Use password to calculate checksum for API requests

I was wondering if it would be an effective way of securing an API by requiring all requests to be checksummed, salted with the users password (or a hashed version)? With securing I mean making it ...
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1answer
33 views

Format of hashed strings [closed]

When hashing a string, sometimes I see the format like so: {SHA512}1G2zjh2Bso/LzS06JDLXcELCJX4TQm7oXL5Et3Yg4Veyji7iQW26VnBdEHiURM5evO6duJjzY5387mkWV0oiyYA= Specifically the section indicating the ...
5
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2answers
114 views

When can you not use strcmp?

I've read that one shouldn't use strncmp(userSuppliedPassword,origPassword,sizeOfArray) (or String.equals in Java) since one can use a timing attack to guess the password. Rather, one should use a ...
16
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4answers
6k views

How quickly can these password schemes really be beaten?

If you use a quick hashing algorithm like MD5 or SHA-1 to hash passwords and you don't use any salt at all, how quickly could one expect a hacker to find my password out? If I use a truly random salt ...
390
votes
5answers
130k 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 ...
5
votes
1answer
2k 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 ...
17
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4answers
2k views

Why would a website serve different versions of a file over HTTP and HTTPS?

Here is a link given on curl's official website: (prefix omitted) bintray.com/artifact/download/vszakats/generic/curl-7.46.0-win64-mingw.7z When I downloaded it with prefixes http:// and https:// I ...
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2answers
212 views

What if the Local Windows Cert Store is Compromised?

The diagram below illustrates chaining digital certificates up to a publicly trusted Root Certificate: I have been researching how trusted root authorities (such as GlobalSign or Verisign) are used ...
3
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2answers
197 views

Hashing password multiple times with different random salts

I have read a lot of answers about this topic like: https://programmers.stackexchange.com/questions/115406/is-it-more-secure-to-hash-a-password-multiple-times. ...
0
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1answer
27 views

First string in hash collisions bucket

My understanding of hashing is conceptual at best and I'm assuming things that I'm not sure of and it leads me to a question that I don't even know if it's founded or not. So please correct my ...
5
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1answer
103 views

Random string vs hash(random string)?

I'm implementing a one-time token service. Each of these one-time token represents some server side data/action associated with it (a 'email confirm' action for example), so that my web service can ...
3
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2answers
72 views

Sign a callback URL

I have a Single Sign-On system that works this way : User clicks link on clientsite.com that redirect him to mastersite.com?returnTo=http://clientsite.com If auth is valid, the user is redirected ...
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2answers
279 views

Is this hash function safe?

Below is the hash function implementation of the roguewave library. It returns a 32 bit hash. The core operation is A = B ^ ((C << 5) | (C >> 27)). Is this hash safe to use as a password check ...
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1answer
56 views

Is there any kind of encryption that returns constant number of characters?

I wonder if there is any kind of publicly known encryption (not hashing) algorithm that generates constant number of characters independent of the input. I have came across an online platform that ...
3
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1answer
257 views

John the ripper is not identifying hashes

I'm attempting to use JTR against a password protected zip. I have created the hash file using:zip2john filename.zip > filename.hash and i get a successful output:file.txt is using AES encryption, ...