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Questions tagged [sha2]

SHA2 is a family of cryptographic hash algorithms, including SHA256 and SHA512. These are the successor to the SHA1 algorithm.

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A Method for Generating Un-Guessable Client Identifiers

I am implementing an OAuth 2.0 authorisation server. As part of client registration process I want to generate the unique client identifier for this client. The method I have chosen is to take all ...
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2answers
214 views

Is there a cryptographic disadvantage to applying bcrypt to an already hashed password

I originally asked this on stackoverflow, but due to lack of traction and a recommendation by a user there I have asked it here too. Imagine a scenario where a client application is sending a ...
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0answers
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How Secure Would Client Side Sha-512 Be In JavaScript

I've created an Capture The Flag challenge for me and a few of my mates, and for the final challenge, you're goal is to log in as admin to a site. Now the site doesn't use any server side languages (...
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3answers
106 views

Are Salt strings stored by application? [duplicate]

1) As storing passwords in plain text in databases are not secure and so is not a good practice. password stored in db = "abcde" (plain text) 2) To avoid this, passwords are stored after being hashed ...
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1answer
274 views

Is it safe to use SHA-512 to identify credit card?

I am thinking if using one-way function like SHA-512 is considered to be safe for application on credit card numbers. The credit card number is 13-19 number with known BIN range (6-8 numbers) and the ...
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0answers
23 views

SHA 1 Interemediate Signer for a SHA2 Personal Certificate [duplicate]

I came across a certificate that has a signer that is SHA1 but it is a SHA2 certificate. Is this actually allowed or is did the CA screw up ? Would it work with a TLS 1.2 negotiation?
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2answers
133 views

Does flagging a file as read-only prevent a hash from changing?

Some time ago I developed a simple script to detect duplicated files. It works in the following way: Locates Excel files in a folder. Obtains SHA-256 of the file. Stores a mapping between Filename - ...
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3answers
2k views

Rounds in a hashing function

First of all, Hello! I'm new to the site, don't know any english equivalent to "yoroshiku". So, I was reading the SHA-512crypt generator documentation and found the part: The default number of ...
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1answer
146 views

Extra PBKDF2 characters in SHA-512 output

I was using hash_pbkdf2 earlier today when I noticed something strange. The normal way to generate a hash is to output the entire string like the code below which outputs a 128 character string (128 ...
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1answer
115 views

Finding SHA-2 collision

What would be the implications if finding a collision in the SHA-2 hash function? Would there be a greater impact if more than one were found, or would it be the same in principal?
6
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1answer
3k views

How vulnerable is IPSec HMAC-SHA1

There are a few references out there that say HMAC-SHA2 must be used over HMAC-SHA1. If I am using an IPsec link with HMAC-SHA1, how vulnerable is it to being intercepted and cracked?
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2answers
505 views

Would it be a good approach to hash twice? [duplicate]

Lets say I have a system in which I save the user's passwords using SHA-2. Now I was just wondering would it be a good approach if I take the MD5 hash of the password and then compute SHA-2 for the ...
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0answers
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Can an rdiff signature of a file be made public without disclosing non-public information?

I'm building a system which involves passing around what are essentially uncompressed TARs of linux userlands including some additional private files. An original file (X) is sent to a worker, and the ...
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2answers
175 views

Reissuing certificates with SHA-2

I recently setup my own CA, and imported the CA cert into devices across the company. I then deployed certificates to our various servers, etc.. All using SHA-1 signatures (the default in the tool I ...
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1answer
256 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 ...
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1answer
135 views

Unconditionally Secure Authentication

I'm trying to add the authentication for my One-Time Pad implementation. I know that to provide Unconditionally Secure Authentication I need to use the One-Time MAC authentication. But I don't ...
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2answers
985 views

Is a SHA-256 signature required on a CSR in order to generate a certificate with SHA-256 signature?

I've heard conflicting statements about this from certificate authorities and security groups and would like to confirm: Is a SHA-256 signature required on a CSR in order to generate a signed ...
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2answers
2k views

Will a wildcard SSL work properly for an A record subdomain pointing to another domain/website?

Client has wildcard SSL for his domain/subdomains. The application we are building is on one of our linux servers using one of our IP addresses and is contained within an account named www.somedomain....
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1answer
91 views

Issue regarding installation of SHA256 scertificate

Can anyone help me with the installation of SHA256 certificate? I have generated the certificate perfectly but there seems to be an error below: Kindly let me know why am getting the exclamation mark ...
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5answers
2k views

Is this way of encoding cryptographic hashes safe?

I'm looking at the code of a particular web application that handle file uploads. For some reason, instead of using the cryptographic hash function (SHA-256 in this case), they derive an ID from it, ...
3
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2answers
2k views

Decoding SHA-512 value

How does the SHA-512 decoder on the following page work? http://md5hashing.net/hashing/sha512#main Hash values supposed to be unable to reverse. Is this page fake?
2
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1answer
915 views

Hashing algorithm for cryptsetup

I will encrypt my SSD using cryptsetup and I would like to know which hashing algprithm to use. First of all, cryptsetup benchmark: PBKDF2-sha256 262144 iterations per second PBKDF2-sha512 ...
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4answers
2k views

Getting password cracking time and byte storage from bruteforce?

I am stuck with this question, you can see it in the picture I have included below. PARTS (a and b) I know a-z will be 26^8, A-Z will be 26^8 guesses, and 0-9 will be 10^8 guesses. But I can't relate ...
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4answers
719 views

Confidentiality of file hashes

Context: I have a directory full of sensitive company files. I want to compare these files with a colleague at a remote location, without the need for a secure connection. Is it safe for me to ...
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2answers
4k views

Which hashing algorithm is ideal for use on the web? [duplicate]

I am new here, and have poked around the site looking for an overview of which hash algorithm to use on the web and why. It seems to be the consensus that SHA-256 or other SHA-2 family algorithms are ...
2
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1answer
396 views

How difficult it is to solve a salt if knowing the original data and the hash output that uses the SHA-2 algorithm

I am reading the documentation for Kentico where it describes using hashes to validate query strings EX:http://localhost/KenticoCMS8/cms/getfile/2d003444-9a27-43c9-be97-4f5832474015/...
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2answers
7k views

iOS, Android, and OS X SHA-2 support (in the context of SSL/TLS certificates)

As there is currently a move away from SHA-1 being used as part of TLS, we're examining moving our SSL certificates, used to protected traffic in transit to/from our webservers, to use SHA-2. However,...
2
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2answers
572 views

Does sending two different hashes of the same password reduce security?

I'm updating a login system. The password is sent to the server as SHA512(password + long_string). I want to switch this to something like SHA512(username + password) in the future. By doing that I ...
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1answer
1k views

Reversing a block hash of SHA-1 with known Plaintext?

Is it possible to reverse the hashing of a block in a Datastream fed to an SHA1 if the plaintext for that block is known? If it is not possible (which I assume) does it make attacks to retrieve the ...
6
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1answer
8k views

Are there sha 512 rainbow tables available? [closed]

Are there sha 512 rainbow tables available for download or what kind of dimensions and processing power would be required to generate them?
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2answers
8k views

Rounds of MD5 and SHA512 Hashing Algorithms

What is the exact number of rounds employed by the MD5 and SHA512 hashing algorithms? According to various sources, the SHA512 hashing algorithm employs a total of 80 rounds (http://en.wikipedia.org/...
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2answers
267 views

What is the meaning of the term “simple string” for the SALT string in Unix crypt using SHA-256 and SHA-512?

In Unix crypt using SHA-256 and SHA-512 the author, Ulrich Drepper, introduces the SALT string as the following (highlight by me): For the SHA-based methods the SALT string can be a simple string ...
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3answers
6k views

What does GUID have, that a Whirlpool, MD5 or SHA-2 hash don't?

I'm trying to understand the use of GUID and what has always left me wondering is what's so special about them that I should consider using them instead of rolling my own type of unique ID. In other ...
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5answers
3k views

Gold Standard for password hashing

I've developing a web application that will be dealing with highly sensitive information and I want to ensure the hashing of passwords is gold standard. Ideally I'd go for per-user salted SHA512 ...
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4answers
30k views

What is SHA-3 and why did we change it?

On the 2nd of October NIST decided that SHA-3 is the new standard hashing algorithm, does this mean we need to stop using SHA-2 as it is not secure? What is this SHA-3 anyway?
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0answers
310 views

Recomended hash algorithm [duplicate]

Possible Duplicate: How to securely hash passwords? Do any security experts recommend bcrypt for password storage? What would you choose between: PBKDF2 SHA256 (270,000 iterations) bcrypt (12, ...
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1answer
3k views

How many possibilities can today's computers check (per second) in a SHA512 hash of a 50-byte-long random entry? [closed]

The problem I want to avoid is "brute force" attacks against a database. So if I add a 50-byte-long cryptographically random salt to my information (which I don't need to retrieve, just its hash) - is ...
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1answer
659 views

What is the application of SHA384withRSAEncryption?

I am trying to understand the application of SHA384withRSAEncryption. SHA-384 is a message digest algorithm and RSA is used for public key cryptography (secure communication). RSA involves a public ...
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1answer
6k views

Using PBKDF2 with AES and SHA2

I use the following inputs to encrypt using AES: UserPassword (plain text) SecretKey RandomIV I use the following inputs to encrypt using SHA512: UserPassword (plain text) RandomSalt I'd like to ...