Sha256 is a hashing algorithm.

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SHA256.DB30.com listing of email account

After searching a gmail account in Google I've found a result for the website SHA256.DB30.com. The page just shows the name of the gmail account and a list with major and minor hash. From my basic ...
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1answer
51 views

PKI - Security concerns when changing a certificate hash algorithm

Suppose I want to change the hash algorithm used for a certificate signature (ex: SHA1 to SHA2). Is it better to revoke the previous certificate and issue a new one with expected hash algorithm ? Or ...
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2answers
63 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, ...
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1answer
139 views

Someone help me decode this [closed]

What type of hash is this? a9df6dcd35f4e7223ff3dd087abcc266 I can't find anything when I decrypt it. Please someone decrypt it
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2answers
46 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 ...
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4answers
713 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 ...
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2answers
99 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 ...
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2answers
528 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 ...
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0answers
144 views

Ruby OpenSSL vs Linux openssl

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 ...
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2answers
296 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 ...
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1answer
88 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 ...
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1answer
445 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 ...
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1answer
749 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 ...
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2answers
147 views

How to use ESSIV to avoid seeing repeated patterns?

I'm trying to implement an encrypted file-system. The file-system consists of 512-byte sectors. I encrypt/decrypt the contents of a sector as follows: Compute the SHA256 sum of the user password. ...
0
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1answer
96 views

Using multiple hash-functions along the line [duplicate]

I was wondering what the effect on strength/security is If I would use an aggregate of multiple hash-functions. For instance, I don't want to sent passwords in plain text (although it's over an ...
0
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1answer
127 views

Bcrypt SHA-256 implementation [duplicate]

i need bcrypt to create encryption keys and also for authentication hashes, but entropy of delivered output from password has to be >256bit (which clearly can't be achieved by hashing 196bits with ...
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1answer
626 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 ...
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1answer
2k 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
249 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 ...
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1answer
551 views

How to encrypt by AES-Twofish-Serpent

I was wondering how to encrypt by doing a AES-Twofish-Serpent encryption. Does this mean I encrypt in AES first then after that in Twofish, and after that in Serpent (three separate encryptions). ...
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1answer
131 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
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1answer
1k 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 ...
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1answer
85 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. ...
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1answer
1k 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 ...
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2answers
1k 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 ...
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3answers
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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 ...
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1answer
537 views

what does GUID have that a whirlpool, md5 or sha2 hash dont

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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2answers
5k 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 ...
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1answer
2k 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 ...
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2answers
675 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
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2answers
639 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 ...
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1answer
4k 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 ...
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7answers
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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 ...
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1answer
3k 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). ...