Secure Hash Algorithm is a family of cryptographic hash functions published by NIST.

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HMACSHA512 versus Rfc2898DeriveBytes for password hash

We are currently using HMACSHA512 in .net, with a 128Char (64byte) validation key The salt is 64 char randomly generated string. We allocated 2048 length on the database for the hashed base64 string ...
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2answers
74 views

If I only know part of a password and part of the hash is it possible to get the full password?

I'm trying to learn more about hashes and cryptography and doing my own pentesting, but I seem to be stuck on this problem. The hash function being used is SHA1. If I'm trying to determine a ...
1
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3answers
280 views

About SHA1 in default Disk Encryption in Linux

Link to the thread: Recommended options for LUKS (cryptsetup) I wonder what's the exact difference between SHA1 and SHA512. I know that SHA512 has a longer key but I've read that it doesn't matter ...
4
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1answer
144 views

Should SHA-1 be used with RSA-OAEP?

PKCS#1 defines SHA1 as a default hash function and all implementations support this hash function and the mask generation functions based on SHA1. In some implementations you can change the hash ...
1
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0answers
18 views

Should SHA-1 be used with PKCS #1?

I came across this excellent question and answer: Should SHA-1 be used with RSA-OAEP but it only covers RSA-OAEP. RSA-OAEP is not the only place in PKCS #1 where a hash function is used. Should we ...
34
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5answers
5k views

Should I trust a website which uses a SHA-1 HTTPS certificate?

I am on a website where I need to pay for something. This website has the following warning in the top left: This site uses a weak security configuration (SHA-1 signatures) so your connection ...
4
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1answer
267 views

OpenSSL 0.9.6a PRNG algorithm weakness: How to exploit?

I saw an OpenSSL security advisory for Openssl 0.9.6a Recently a cryptographic flaw in OpenSSL's built-in pseudo-random number generator (PRNG) was pointed out to us by Markku-Juhani O. Saarinen <...
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1answer
35 views

Possible number of collisions in a hashing function with constant message size

Jumping to conclusions from my question, can we predict possible number of collisions for a given message in a given hashing algorithm. Say I am using SHA-1 which outputs 160 characters string, and ...
-1
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1answer
57 views

Shouldn't multiple images always exist even in most powerful hashing algorithm?

I have a confusion in mind that since in hashing we transform a large string into a smaller fixed size string, so its unlikely that any large string has a unique hash. There had to be collisions and ...
50
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4answers
114k views

Is SHA1 better than md5 only because it generates a hash of 160 bits?

It is well known that SHA1 is recommended more than md5 for hashing since md5 is practically broken as lot of collisions have been found. With the birthday attack, it is possible to get a collision ...
-5
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1answer
84 views

Time to break SHA-512 [closed]

From http://stackoverflow.com/questions/6776050/how-long-to-brute-force-a-salted-sha-512-hash-salt-provided, to break SHA-512 with brute force strategy, it require 3,17 * 10^64 years. It is almost ...
0
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2answers
52 views

How to properly hash a key? big vs small digest

We have to roll (decommission) database access keys often, but it's important to know which key each system is using in order to avoid removing a key in use thus creating unavailability. We want each ...
3
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1answer
234 views

Why does my SHA256 certificate get encrypted with 168 bit 3DES?

We use S/Mime certificates for internal emails within our company. The certificates signature algorithm are all SHA256RSA with a hash of SHA256. I have confirmed the public keys are RSA(2048bits). ...
3
votes
2answers
281 views

Why is 128bit AES considered very strong but 160bit SHA depreciated?

Why is 128bit AES considered very strong but 160bit SHA 'insufficiently secure'? Google/chrome/browsers seems to drop support for SHA1 SSL certificates. I assume it's more simple to calculate SHA than ...
3
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1answer
43 views

SHA 1 no impact to root certificate

I ran a scan on a server and the results of the authentication for digital certificate was as follows : Certificate 1 (root) signature algorithm: Sha256withRSA Certificate 2 (chain of trust) ...
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2answers
68 views

Upgrading security of hashed passwords [duplicate]

Let's say we have a database with usernames and passwords, where the passwords are naively secured using a single round of SHA-1 (such as was kinda best practice a number of years ago). Now, let's ...
3
votes
1answer
69 views

Is SHA1 / PBKDF2-HMAC-SHA1 indissociable from random data?

I want to make sure that the result of PBKDF2-HMAC-SHA1 is indissociable from random data (given random parameters). Basically, PBKDF2-HMAC-SHA1 looks like just a bigger SHA-1 hash, which is normal ...
14
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2answers
359 views

How does SHA3 (Keccak & SHAKE) compare to SHA2? Should I use non-SHAKE parameters?

Keccak is the winner of the SHA3 competition. Since Keccak is highly customizable (presumably for security/memory/time/speed tradeoffs) there does seem to be some controversy around how Keccak ...
3
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2answers
176 views

Is signing android apk file with SHA1 digest secure enough?

Google command line example for signing apk files: $ jarsigner -verbose -sigalg SHA1withRSA -digestalg SHA1 -keystore my-release-key.keystore my_application.apk alias_name source: http://developer....
6
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2answers
1k views

Can I use SHA-512 hash as AES key?

I want to combine hashing and encryption for better security. So can I use a hash key generated from SHA-512 as a key in AES. For example, I have a password "secret", I calculate SHA-512 hash for it ...
6
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2answers
173 views

How is SHA-1 insecure if it is not vulnerable to what MD5 is?

I have been hearing a lot lately about how SHA-1 is no longer going to be used because of how weak and insecure it is, but if it is not vulnerable to collisions like MD5 is, then how is it weak and ...
0
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1answer
84 views

Checking a salted hash against known password?

I've created a mysql dump of my users and passwords and awked them into a presentable form: Passwords: '...
11
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3answers
449 views

How will SHA1 deprecation affect internal CA's?

I am hearing that the SHA1 Deprecation notices from MS/CHROME only apply to certs that are a part of a public trusted root program. This makes one believe that IE will have new logic built in to allow ...
5
votes
2answers
154 views

Why is weakness of SHA-1 considered a threat to TLS security

If I understand correctly the role that a hashing algorithm (e.g. SHA-1) plays in TLS certificates is as follows: The hashing function is applied to a subject's public key. The CA then uses their ...
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2answers
76 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 ...
18
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4answers
4k views

Have weaknesses in SHA-1 and MD5 ever actually been successfully used in an attack?

Pretty much every guide, how-to, and reference for dealing with passwords and hashing has a warning in big or bold letters stating something along the lines of: SHA-1 and MD5 are NOT secure and ...
7
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2answers
542 views

Will Google block HMAC-SHA1 along with SHA1 signed certificates?

So, right now, there is a push for moving from SHA1 signed certificates to SHA256 signed certificates by Google. My understanding is that you cannot use SHA1 for signing certificates but HMAC-SHA1 can ...
2
votes
1answer
179 views

Is this PHP TOTP (time based one time password) idea sound?

Disclaimer: I am not very familiar with safety techniques in general. The problem: Quickly create lots of small files in server from a bash script. I used to use scp (secure copy) in order to create ...
2
votes
1answer
42 views

Online shops SSL certificates and VISA/MasterCard

Is it still allowed to use SHA-1 certificates on VISA/MasterCard payment pages? If yes, will it be prohibited and when? I know about browsers are going to show it as non-secure after some time, but ...
5
votes
2answers
143 views

Why are we using SHA3-512?

As we know, hash algorithms can be used for authenticity of a message. In my understanding, since the message lengths are too large, we convert it into a hash value using hash algorithms and these ...
15
votes
7answers
9k 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 (http://social.technet.microsoft.com/wiki/contents/...
4
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1answer
97 views

Should my company change the internal Root CA hash method from SHA-1 to SHA-2?

My company have a Root Certificate Authority which is installed on a Windows Server 2003 and uses SHA-1 as hash method. We will migrate to Windows Server 2012. Checking the root certificates of my ...
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4answers
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SHA-1 deprecation and self-signed certificates

I am confusing regarding SHA-1 deprecation. We use self-signed certificates signed with SHA1 and the expiration is after 1 January 2017. According to this blog: http://blogs.technet.com/b/pki/...
0
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1answer
3k views

When and how will Internet Explorer refuse sha-1 certificates?

sha1 certificates are deprecated. The web browser Google Chrome shows a red security warning for the website https://sha1-2017.badssl.com/ (sha1 certificate expires in 2017). It shows neutral (neither ...
2
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1answer
273 views

Microsoft and SHA-1 deprecating on Windows 7

Microsoft states: Effective January 1, 2016, Windows (version 7 and higher) and Windows Server will no longer trust any code that is signed with a SHA-1 code signing certificate and that ...
13
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1answer
3k views

What's the hash for in ECDHE-RSA-AES-GCM-SHA?

Presumably the SHA is for deriving the AES key from the shared secret. Where else is the hash used? ECDH just does ECC (no hashing). RSA does masking and padding but this doesn't involve the ...
3
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1answer
239 views

Getting a certificate warning for one email but not another

When I log into outlook.com using Chrome browser, I get a certificate warning for one account but not another. One says my connection is private, the other says it "may not be private". Here are the ...
34
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4answers
4k views

Does every hash value have an inverse value?

There are many different hash functions, md5, sha, and others. They take a value V and produce a H via transformation Function(V) = H, where Function is md5, sha, etc. My question is: Does every hash ...
2
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2answers
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Is this a secure Digital Signature + Encryption method?

I am trying to wrap my head around Digital Signatures and how RSA Encryption supports them. And which order to do them along with what specifically to encrypt. So say we have Alice and Bob and a ...
19
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2answers
2k views

How safe are signed git tags? Only as safe as SHA-1 or somehow safer?

How safe are signed git tags? Especially because git uses SHA-1. There is contradictory information around. So if one verifies a git tag (git tag -v tagname), then checksouts the tag, and checks that ...
0
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1answer
53 views

Software activation “by phone” [closed]

I'm a software developer, and I would like to protect my application in an offline way, like many software do activating by phone. Following a screenshot taken from google images on what I would like ...
0
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1answer
92 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 ...
2
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0answers
59 views

cracking krb5 passwords (des3-hmac-sha1 and des-cbc-crc )

I'm trying to audit kerberos passwords. The available formats are des3-hmac-sha1 and des-cbc-crc but I cannot find a possibility/a tool to crack them. For other hash-types I used John the Ripper, but ...
1
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2answers
98 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 ...
4
votes
2answers
227 views

Why did browsers deprecate 1024-bit RSA, but retain SHA-1?

I was reading Mozilla's security blog Phasing out Certificates with 1024-bit RSA Keys. Effectively, some browsers are deprecating 1024-bit RSA for CAs and Subordinate CAs because the certificate must ...
3
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2answers
2k 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 ...
4
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1answer
130 views

Using Nokia feature phones with new SHA256 Certificates

Our site needs to provide SSL authentication with a number of older devices. These devices (mostly old Nokia Feature Phones) have a limited number of root certificates and are only able to ...
2
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3answers
11k views

Why does MD5 hash starts from $1$ and SHA-512 from $6$? Isn't it weakness in itself? [duplicate]

I have moved this question from stackoverflow to this place. I know it may be a question about 'opinion' but I am not looking for a private opinion but a source of the final decision to keep it this ...
42
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4answers
3k views

Is using bcrypt on existing SHA1 hashes good enough when switching password implementation?

I'm working on improving a CMS where the current implementation of storing password is just sha1(password). I explained to my boss that doing it that way is incredibly insecure, and told him that we ...
1
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2answers
80 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 ...