Sha256 is a hashing algorithm.

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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 ...
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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 ...
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1answer
31 views

Can SHA1 certificate be used for SHA256 cipher?

I have two Windows 2008 R2 domain controllers configured with TLS 1.2. Both certificates are SHA1-RSA. I captured network traffic between two DCs while running LDAPS (LDP.EXE). It seems TLS 1.2 was ...
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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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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 ...
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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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should I add a sha256 signature to an AES_256_CBC encrypted token?

currently I generate a token for an mobile app the way below. I decrypt the token to process the request and assess the user is logged in. I'm on TLS RSA 2048 bits connection. I was wondering if ...
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1answer
114 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 ...
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2answers
70 views

Is this explanation about how SSL Certificate Signatures work correct?

I was reviewing some information about SSL certificates and came across an explanation I believe to be incorrect. The explanation is of how signatures and hashing algorithms work in the context of ...
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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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743 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 ...
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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 ...
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126 views

Understanding the HMAC Algorithm (SHA-256)

I've posted a related question on Stack Overflow, but I have a more general question about HMAC and SHA256. Let's say I want to generate an HMAC hash for a blank key and a blank message. The ...
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827 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 ...
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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 ...
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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 ...
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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 ...
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266 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 ...
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SHA-2 migration considerations

due to SHA-1 being in the path of deprecation, i will be migrating my SSL certs to SHA-2. Besides creating CSR using SHA-2 for signing, what other considerations should I take note of? I believe one ...
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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 ...
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1answer
714 views

Decrypting SHA-256 with known plain text

If i have a SHA-256 hash and I know what could be the crypted string is it possible to decode it faster? Lets say I know the string is formed like this : %d-%d-%d-%s %d being numbers from 1-25 %s ...
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1answer
660 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. ...
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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 ...
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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 ...
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SHA256 to text or MD5

I want to decrypt a sha256 to text. Is there a way other than bruteforcing to decrypt sha256? Like if I convert that SHA256 to MD5 and then try decrypting?I know its hard and the possible way for ...
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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?
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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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161 views

Could overlapping SHA256 hash begin to loop at some point?

I have a system that needs to send a key to the user. This key is used for validation after work and needs to be shown that we do not change it mid-work so we send to the user in the middle of work a ...
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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 ...
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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
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 ...
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2k views

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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130 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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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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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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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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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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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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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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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 ...
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2answers
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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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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 ...
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1answer
552 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
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 ...
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330 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. ...
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144 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 ...
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256 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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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 ...
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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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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 ...