Sha256 is a hashing algorithm.

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40
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2answers
17k views

What is the relationship between “SHA-2” and “SHA-256”

I'm confused on the difference between SHA-2 and SHA-256 and often hear them used interchangeably (which seems really wrong). I think SHA-2 a "family" of hash algorithms and SHA-256 a specific ...
32
votes
7answers
12k views

How can crackers reconstruct 200k salted password hashes so fast?

I'm researching for a small talk about websecurity and I found one article about the formspring hack, which made me curious. They claim to have used SHA-256 + salt We were able to immediately fix ...
24
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6answers
3k views

Is sha1sum still secure for downloadable software packages signature?

We use sha1sum to calculate SHA-1 hash value of our packages. Clarification about the usage: We distribute some software packages, and we want users to be able to check that what they downloaded is ...
12
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2answers
9k views

SHA256 security: what does it mean that attacks have broken “46 of the 60 rounds of SHA256”?

Wikipedia reports Currently, the best public attacks break 46 of the 64 rounds of SHA-256 or 46 of the 80 rounds of SHA-512. What does this mean, and how safe is SHA-256 expected to be in the ...
12
votes
1answer
553 views

Is the Litecoin Scrypt hashing technique a threat to hashed passwords?

The Bitcoin alternative, Litecoin uses a different algorithm to protect the block chain, namely Scrypt (not Sha256). Given that GPU accelerators exists, and ASICS are due to be released, does the ...
11
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6answers
2k views

Deprecation of SHA1 code signing certificates on Windows

I have been keenly following the issues with regards to Microsoft deprecating the use of SHA1 code-signing certificates for Windows executables ...
10
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3answers
5k views

How secure are sha256 + salt hashes for password storage [duplicate]

I started reading about password hashing recently on multiple sites like this page on crackstation and others, and for what I have understood, I should avoid using hashing algorithms like md5 and sha1 ...
10
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3answers
13k views

With ASIC bitcoin miners, should SHA256 be considered insecure for password hashing?

I'm sure everyone here has seen the rise and further rise of bitcoin. The process used for mining bitcoin is basically "let's brute force an SHA256 hash that is less than this amount" That being ...
7
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2answers
3k views

Truncating the output of SHA256 to 128 bits

suppose we need/prefer 128 bit hash output. for example to generate a 128 bit encryption key or, in other applications (e.g. file integrity verifications), to consume less storage space. i don't know ...
6
votes
1answer
5k views

Is BCrypt enough when saving a password into a database?

In order to allow users to connect to my website, I encrypt their password using BCrypt since it is one of the slowest algorithms to decrypt (making a compromised database longer to be decrypted). ...
6
votes
2answers
267 views

Do I REALLY need to change my LastPass password?

Last weekend LastPass' network was compromised and that a list of email addresses along with the hashes of the master passwords were stolen. It is being recommended that LastPass users change their ...
6
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1answer
6k views

Is PBKDF2 only SHA1 in C#?

I can't find a way of specifying the hashing algorithm used by the PBKDF2 (the Rfc2898DeriveBytes class) implementation in C# System.Security.Cryptography. It seems to be just SHA1. Am I missing ...
6
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1answer
267 views

What are the pros and cons of using sha256 to hash a password before passing it to bcrypt?

My apologies if this has already been asked. I recently became aware of the fact that bcrypt truncates passwords to 72 characters. Practically speaking my intuition is that this does not pose any ...
5
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1answer
3k views

Security of bcrypt/sha256 key used with AES to encrypt a file

I'm looking to encrypt files using secure hashing and encryption algorithms in Python. Having used bcrypt in the past, I decided to use it for my passphrase calculator, then pass the output through ...
5
votes
2answers
165 views

which memory hard hashing algorithm can equalize low-computational and high-computational power devices to utilize blockchain in the IoT?

Recently IBM and Microsoft showed their interest (IBM post, Microsoft post) in utilizing bitcoin's blockchain for internet of things (IoT) development. Let's assume that in close future the blockchain ...
5
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1answer
111 views

How does combining SHA256 with RIPE-MD160 compare to SHA256 + SHA-3?

Bitcoin stores its addresses as a combined SHA256 + RIPE-MD160 hash. Is it correct to assume this is done to prevent a failure in the algorithm? Since SHA3 was designed to be an alternative to ...
4
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2answers
115 views

Password manager's hash choices (scrypt + sha256)

Background information: Master password is a stateless password manager. It (deterministically) generates a password using a hash function, depending on your master password and the site name (also ...
3
votes
2answers
882 views

User authentication + database encryption with same password

I'm working on a private project where I need to store a users financial data in a database. I'll encrypt this data using AES, and I'll be using scrypt to generate a AES ecnryption key from a more ...
3
votes
2answers
7k views

Client-server encryption technique explanation (TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, 128 bit keys)

I opened a web page using https. When I looked at the page info provided by my browser (Firefox) I saw following: Connection encrypted: High-grade Encryption ...
3
votes
2answers
700 views

What risk does commoditized dedicated SHA256 processors pose to IT Operations?

With the advent of GPU-based computing, and now commoditized/dedicated SHA256 processors, what risk does this hardware pose to cryptography? What security algorithms should be closely watched or ...
3
votes
2answers
1k 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 ...
3
votes
3answers
552 views

Corporate PKI - SHA1 deprecation

Here is the context. Suppose you have a corporate PKI with : AC_Root (offline in safe store - SHA1 signature) SubRootA and SubrootB (offline in safe store - SHA1 signature) SubSubRootC, SubSubRootD, ...
3
votes
1answer
750 views

Creating an TLS certificate using keytool with SHA-256

I want to create a TLS certificate for my personal tomcat8 webserver on a Debian ARM server. I've done this before, using the following command: /usr/bin/keytool -genkey -alias tomcat -keyalg RSA ...
2
votes
4answers
848 views

Using last characters of hash as salt [duplicate]

In a recent discussion somebody mentioned the following hashing scheme: passHash = sha256(password) saltedHash = sha256(passHash+passHash.substr(-10) finalHash = sha256(secret+saltedHash) The ...
2
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1answer
2k views

NIST test vectors for HMAC-SHA-256

I'm working on an implementation of HMAC-SHA-256 in classic ASP (legacy code). I currently have it working, and the resulting values are correct compared to some test cases I came up with along with ...
2
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1answer
289 views

Attack on the custom token-based sha256 security scheme

I have token made as sha256("public text" + "secret value"), or any number of such tokens with the same "secret value" but different "public text". sha256 that is used is not salted - so that ...
2
votes
2answers
1k 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
121 views

Is it safe to derive an IV partially from the secret data if it is hashed before use?

To help ensure uniqueness of IV's used in a CFB AES-256 cipher, software I know of gathers bits from various sources including the plaintext being enciphered, and runs that through an SHA-256 hash. ...
2
votes
1answer
662 views

Is there a benefit of using stateless JWT over SHA256 hash for API tokens?

Does it make sense to use stateless JWT (without persistent storage) over plain SHA256? Example scenario: User logs in User token generated as follows: a. JWT.encode(userId, 'secret') or b. ...
2
votes
2answers
70 views

Is the HMAC weakened if a part of the message is part the key?

For example: I am using HMAC SHA 256 to sign an XML file. Part of the file data is a version number. If I append the version to my secret to use it as a key, does that weaken the HMAC? As the version ...
2
votes
1answer
64 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 ...
2
votes
1answer
115 views

One-Time Pad authentication & Information-theoretic security

I'm trying to create a "Information Theoretically Secure" cryptosystem, inspired on the One-Time Pad. Now I'm facing the obstacle of authentication... How good is this solution (that uses the "Encrypt ...
2
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0answers
45 views

In DNSSec, are Delegation Signer Records always SHA-1?

I'm creating a RSA/SHA-512 Zone Signing Key and Key Signing Key at Dynect Managed DNS (corporate offering) The Delegation Signer Record that was created is SHA1. Should I be concerned about this?
2
votes
0answers
273 views

Ruby OpenSSL vs Linux openssl [closed]

I have a difficulty reconciling Ruby's OpenSSL library with the standard Linux command line openssl. What I'm trying to do here is encrypt the string mysecretstring with the password foobar but first ...
1
vote
2answers
829 views

which hashing algorithm is better to use to store a password, sha256 or sha512? [duplicate]

which hashing algorithm is better to use to store a password, sha256 or sha512? I know that sha512 is more secure than sha256 but I was wondering if it has some disadvantages or it is completely ...
1
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1answer
157 views

Given Hash digest, calculating any random input

I understand that for a hash function there are an infinite amount of possible inputs that could produce a specific output. So if you're trying to find a specific input that created an output that ...
1
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1answer
2k views

How secure is my private key in the Windows Digital Certificate store?

Many files we download don't have digital signatures. Files may get infected or someone may intentionally modify them on our hard disk. So I wrote a simple file hashing program in c# that creates a ...
1
vote
1answer
921 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 ...
1
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2answers
67 views

Possible to send password in plain text with SHA-256?

I just registered on a site where I had to specify sensitive information, eg. my card number. I got a confirmation mail where my password, the one I specified as my login password, was in plain text. ...
1
vote
1answer
421 views

Reason for using Asymmetric encryption along with SHA256

I got a document with integration with another application. They mentioned I need to hash and then encrypt data with my private key before sending it over HTTPS. By doing this, they are making sure ...
1
vote
1answer
24 views

Time of working generating hash with sha2

It is fragment of pseudocode algorithm SHA2 from wikipedia: break message into 512-bit chunks for each chunk create a 64-entry message schedule array w[0..63] of 32-bit words For me, it means ...
1
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1answer
149 views

If you can break this authentication system then you can break into my house

I'll preface this by saying I know approximately 0 about cyber-sec I've made a server that will allow smart phones to act as a remote control for my house (eg turn lights on/off and unlock doors). ...
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2answers
175 views

File SHA256 checksum failed, but OK on reboot

I downloaded the Windows installer (.exe) for ImageMagick via http (both http and ftp downloads are provided at http://www.imagemagick.org/script/binary-releases.php#windows). Upon executing the ...
1
vote
1answer
3k views

Which is better in “DH-group14-sha1 with hmac-sha2-256” and “DH-group-exchange-sha256 with hmac-sha2-256” from performance and security perspective?

In our product (embedded system), so far we were using diffie-hellman-group1-sha1 with hmac-sha1. But due to security concern we are planning to use diffie-hellman-group14 for key exchange and ...
1
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1answer
3k views

Brute force password cracking with a GPU

How are GPU's provisioned for password cracking? Do all, if not most cracking programs have special GPU aware software or do they just function at the basic driver or API level of the device? Can it ...
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1answer
30 views

Is D parameter of the RSA strong enough to be used as secret for HMAC calculation?

Short question: Is the D parameter of the RSA alghorithm crypthographically strong enough to be used as a secret key for generating SHA-256 hash value? Long question: I'm working on windows platform. ...
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1answer
70 views

Do any browsers support Server Name Indication (SNI) but NOT SHA-2? [closed]

Yes, I know that SHA-2 signature validation is typically done by the operating system (with Mozilla Firefox/NSS and Chrome as of v39 being the exception).
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1answer
38 views

Hashing Based Encryption

Let's say you take a 256 bit key and never use it to encrypt anything. You receive a message with a 16 character unique randomly generated salt pre-pended. You salt your key with the 16 character ...
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1answer
41 views

Can a salt maintain pseudo-randomness after being modified?

TL;DR: How much can a function (such as the one below) modify an initially random string before that string becomes useless as a salt for password hashing? Is there a general rule? # Function ...
1
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1answer
141 views

Minimum SHA256'd UTF8 encoded passphrase length not stored anywhere

For a passphrase that is UTF8 encoded and then SHA256'd, what is the minimum length to achieve a practically collision free result? The implementation is for a 32 byte cryptocurrency ed25519 seed ...