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Questions tagged [sha-1]

SHA-1 is a hash function that is two generations old, no longer considered secure for all uses and should only be used for backward compatibility.

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Why does HMAC-SHA1-96 need to pad message to a multiple of 160 bits?

HMAC-SHA1-96 is performed in AH of IPSec, to have data authentication and integrity. I don't understand why I need to pad message M to a multiple of 160 bit, which is the output length of SHA1. Why is ...
allexj's user avatar
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SKI-based authentication

The idea is to authenticate the TLS peer by verification of the SHA-1 hash of his public key (aka SKI). So Alice meets Bob in person and they exchange SKIs of their public keys. When later they ...
Alex's user avatar
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Is a reduced character space pre-image attack possible for SHA-1?

Given a hash cipher f(sha1($pepper . $plaintext)) where f is some transformation to an 11-byte string pepper is 24 bytes long with a character space of 62 (and is ...
Carmina Martin's user avatar
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2 answers
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Does having a known suffix on the input to PBKDF2 make you more vulnerable?

I have an implementation of PBKDF2, which I know Has two bytes of '=' at the end of the input Has an input length of 24 (which is a Base64 encoded character representation of 16 bytes of entropy) ...
Evan Carroll's user avatar
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On the exposition of SHA-1 attack (known_prefix + user_input + backend_secret)

In this question on sha1(known_prefix + user_input + backend_secret), an answer states that is realistically possible to find the first few bytes of ...
wjwrpoyob's user avatar
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Extracting a secret from a SHA-1 hashing algorithm

Assuming there is a web service that returns the following to an unauthenticated user: SHA-1(known_prefix + user_input + backend_secret) where ...
dan-ros's user avatar
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Are there "light" versions of cryptographic hash functions?

After tinkering with cryptographic hash functions, I started wondering if they do have counterpart functions that would imitate their cryptographic properties but with a lower level of strength in ...
Ryan B.'s user avatar
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1 answer
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How secure is SHA-1 against preimage attacks currently?

We know that SHA-1 is susceptible to collision attacks, but what about pre-image attacks such as poisoning torrents?
Hormoz's user avatar
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What is more secure, HMAC with SHA-1, or with SHA-256 and take a substring?

I'm going to guess the latter, but just wanted to ask here. I want to have a relatively short signature, and my goal is to take a substring of the resulting hash.
Gregory Magarshak's user avatar
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1 answer
1k views

Is sha-256 better then sha-1 in aspects othen then the hash size?

Assume I create a hash using SHA-256 and then take only the first 160 bits of the hash, as the result. is the result more cryptographically secured than SHA-1? Or are the two algorithms equally secure ...
Aviv Aviv's user avatar
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Is it insecure to make HMAC SHA1 message and corresponding hash public?

Not sure about the security implications of making HMAC SHA1 message and corresponding hash public (secret would remain… secret)? Evaluating if that would help an attacker crack algorithm.
sunknudsen's user avatar
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Is HMAC SHA1 algorithm secure in 2022? [duplicate]

Contemplating using YubiKey’s challenge-response feature to hash public passphrases. By public, I mean an attacker could potentially exfiltrate passphrases but, not having YubiKey*, passphrases would ...
sunknudsen's user avatar
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Is it possible to bruteforce a 200 bit hash generated with PBKDF2, in which the first 160 bit are known?

As some password manager, such as KeyPassXC allows a user to create a master password using a HMAC response from a YubiKey concatenated with a password entered by user, I was wondering something. ...
romes's user avatar
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1 answer
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Real world hash collision risk, for finite input; uniqueness only no data risk

I've got a comma-delimited list of identifiers that I need to use for uniqueness. MSSQL limits uniqueness to 1700 bytes, which according to my sampling, doesn't appear to be sufficient. hashes are the ...
Scott Brickey's user avatar
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1 answer
48k views

How easy is it in 2022 to find a SHA1 collision?

Most of the answers I can find date to years back where the first collision(s) were found, but hardware mainly GPUs have progressed a lot in the past few years (with for example the new line of 3090s ...
Hormoz's user avatar
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2 votes
2 answers
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Are SHA-1 hash collisions harder to find when files are big?

Was that just a coincidence, or did the 2 "shattered" pdf files whose SHA-1 hashes are identical had to be small in size (412KB) to make the collision attack easier?
oqdn's user avatar
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Understanding Hash collisions - why bad?

I read few answers about the question: why are hash collisions so dangerous? But did not get a really satisfying answer. Assume we are the first people who found a SHA256-collision, like sha256($§&...
ZPlaya7's user avatar
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Performance of AES CTR + HMAC SHA1

I'm doing a performance test on AES with CTR mode and HMAC SHA1 for message authentication and found the openssl speed tool for that. I run multiple tests with <...
Soteri's user avatar
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1 answer
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What is a differential attack on a hash function? How would one attack a SHA algorithm and what would achieve?

Currently, I have been assigned to attack a reduced version of SHA-1. What are we trying to achieve? How do we attack it?
Drilon Aliu's user avatar
6 votes
1 answer
3k views

Risks of Using SHA1 Instead of SHA256 for RSA with OAEP Padding

I'm presently implementing a simple RSA-based encryption as follows in PHP (using openssl_public_encrypt): ...
azoundria's user avatar
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1 answer
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Is SHA1 break significant for an algorithm intended to be Proof-Of-Work?

Let's say I'm modifying the Scrypt hash function (https://github.com/Tarsnap/scrypt/blob/master/lib/crypto/crypto_scrypt-ref.c) and that all I want to do is replace SHA256 with SHA1 in the code to ...
AManInTheSHAdows's user avatar
1 vote
1 answer
538 views

how high is the possibility of getting a hash collision in text files?

Just for an example, let's say I downloaded "the adventures of tom sawyer" from gutenberg in .txt file format and saved it to my usb thumb drive. And as you can see, usb drive is not an ...
tadkov's user avatar
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2 answers
304 views

Does google's Shattered paper(The first collision for full SHA-1) mean creating a new file with the same hash as the original file?

I have a source data A and a hash H(A) of this A. Is it possible by google's shattered docs to create a new data B that outputs this H(A)? ++ I understood that the content of the paper is to ...
DownTop_oil's user avatar
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1 answer
385 views

To what degree does a high PKBDF-HMAC-SHA1 iteration count compensate for a weak passphrase entropy?

Lost a LUKS-encrypted laptop at the end of 2019 and now trying to figure out the odds of a very sophisticated attacker being able to break in. The LUKS container was created mid-2017 with LUKS1 ...
Peter_Python's user avatar
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0 answers
55 views

Time by "crypto_shash_digest"

I am trying to calculate the time consumed to run SHA1 in the kernel level. I had run the upper codes (inside a for loop) and the following was my result. It first showed about 30micro seconds and ...
Telemore's user avatar
1 vote
0 answers
100 views

Coursera Course or book(s) That covers the following subjects: OPENSSL, SSH, PKI, MD5, RSA, Certificates, keys, signatures

I started working as a developper in a cryptography company 3 months ago where the applications are for mostly windows applications. I found that I don't have enough knowledge concerning the topics ...
Hani Gotc's user avatar
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4 votes
2 answers
2k views

How easy is it to fake a file hashed with three functions, CRC32, MD5 and SHA-1?

File-A is hashed with CRC32, MD5 and SHA-1. How easy is it to create a fake file-B that has the same hashes of file-A? CRC32, MD5 and SHA-1? Can an average PC with a GPU calculate a triple hash ...
user94388's user avatar
0 votes
1 answer
2k views

Is it possible to have a hash in UUID form that ends with 16 characters instead of 12?

You may know how sometimes a hash in a URL may be in UUID format, which consists of groups of hex values separated by hyphens. In UUID format, I have come to learn that this hash takes the form: 8-4-4-...
Rikudou's user avatar
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-2 votes
2 answers
165 views

What are the security flaws of SHA? [closed]

I have been researching SHA algorithms extensively, specifically SHA1, SHA2-256, SHA2-512, SHA3-256, and SHA3-512, and have found many instances of successful collision attacks as well as methods. In ...
Arturo Roman's user avatar
2 votes
1 answer
3k views

What is the role of SHA-1 on Diffie-Hellman-group1-SHA1?

I undersntand that in Diffie Hellman each party generates a public / private key pair and distributes the public key. I know that a combined key is created with the sender private key, and the ...
DevMouse's user avatar
1 vote
1 answer
220 views

What's the use of SHA on Non Digital Signature applications?

What's the use of SHA on Non Digital Signature applications? Why is SHA1 not a risk for Non Digital Signature applications? What's the difference between Non Digital Signature applications vs. Digital ...
DevMouse's user avatar
1 vote
1 answer
204 views

Using SHA1 to obfuscate published resource IDs

First off, yes I do know that SHA1 is cryptographically insecure (and has been for a long time). So this question is more academic than anything. It's also very contrived, but bear with me. I want to ...
oobayly's user avatar
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2 votes
1 answer
162 views

Is the padding wrong on the "Length Extension Attack" Wikipedia page example?

In the Length extension attack of Wikipedia The following information summarizes the relevant information provided on the page at the time of posting this question. The provided parameters are secret ...
ajh158's user avatar
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What technical flaw in the Secure Hash Standard was the NIST referring to?

On July 11, 1994, the NIST proposed an interesting revision to FIPS 180, about the Secure Hash Standard: A revision of Federal Information Processing Standard (FIPS) 180, Secure Hash Standard (SHS), ...
Patriot's user avatar
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1 vote
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vec_sel in SHA-1

I can't find what is vec_sel() in this optimization from Wikipedia: Instead of the formulation from the original FIPS PUB 180-1 shown, the following equivalent ...
Eric's user avatar
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9 votes
1 answer
2k views

Outlook of trustworthiness of SHA-2

On the Wikipedia page of SHA-2, the following is written: Currently, the best public attacks break preimage resistance for 52 out of 64 rounds of SHA-256 or 57 out of 80 rounds of SHA-512, and ...
matthias_buehlmann's user avatar
2 votes
2 answers
2k views

Question about SSH host key algorithms

I'm currently writing a report for my Master's degree on the SSH protocol. Quite interesting! However I'm having trouble getting into the inner workings of the host key algorithms. For example, ...
yaroze's user avatar
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2 votes
1 answer
327 views

How can Hashed Value be same in length extension attack?

Let's say we had the following information: Secret = "Hello" Message = "Attack at Dawn" H(s,m) = ABC Alice is sending a message to Bob but there is a person in the middle, ...
MrNewbieCoder's user avatar
4 votes
2 answers
1k views

Embedding SHA256 inside SHA1 for BitTorrent

BitTorrent uses SHA1 for its hashes, but SHA1 is unsafe and people can tamper the preimage and still obtain the same hash, right? So imagine I want to be very sure the file I'm sharing on BitTorrent ...
fiatjaf's user avatar
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1 vote
1 answer
789 views

is MAC double-hashing enough to prevent length extension attacks?

I know that $$mac=\operatorname{SHA1}(secret\mathbin\|message)$$ is prone to length extension attacks, but what about: $$mac=\operatorname{SHA1}(\operatorname{SHA1}(secret\mathbin\|message))?$$ In ...
hanshenrik's user avatar
8 votes
3 answers
8k views

How to get an output of SHA-1 with first 2-bit are zeros?

Can someone explain what are the ways to get an output of SHA-1 with first 2-bits which are zeros?
Denver1212's user avatar
4 votes
2 answers
1k views

The length extension attack and security on length shortening of a hashed message by one byte

MD5, SHA1, SHA2 are vulnerable to length extension attacks Wikipedia:Length extension attack. Could is also be possible to generate $H(\text{message}[1..n-1])$ from $H(\text{message}[1..n])$ if I know ...
Unlikus's user avatar
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0 answers
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Security implication of concatenating two hashes using different algorithms

Background Hashing files is an expensive thing for CPU. I am tasked to write a secure digital signature scheme. For that, I decided to check the integrity of files using Hash/Digest. To be more secure,...
Eirtaza's user avatar
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0 answers
67 views

Should I update my fedora encrypted system?

I have installed my Fedora Workstation version 23 using native disk encryption. Since it, I am upgrading it using dnf system-upgrade plugin. Today, I have fedora 32. Some time ago, I’ve discovered ...
vdTOG's user avatar
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-1 votes
1 answer
243 views

Collision attack

I want to perform a collision attack using hash function of my student number and another possible student number with same hash value. How can I perform this? is there any online tools that can help ...
Denver1212's user avatar
1 vote
0 answers
405 views

Kerberos Use of SHA-1

A lot of good information on Kerbero's encryption methods discussed here, but I there is a second question that arises. Does use of SHA-1 in the overall algorithm weaken Kerberos? If so, will ...
PrometheusRising's user avatar
1 vote
2 answers
270 views

Losing entropy after re-hashing a hash

Suppose you have a string AAA that was hashed with SHA1 to produce 606ec6e9bd8a8ff2ad14e5fade3f264471e82251. If I rehash ...
jimmytann's user avatar
  • 177
2 votes
1 answer
586 views

Security Considerations in using SHA-1 for One Time Passwords

SHA-1 is considered broken. That's why I'm assuming that using SHA-1 for RFC2289 OTPs is broken as well. Is this assumption correct? Going further with this assumption using SHA-1 for RFC4226 HOTPs ...
Fandi's user avatar
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2 votes
1 answer
3k views

Length Extension attacks in SHA1 and MD5?

From my understanding on the internet about length-extension attack, I have understood that hash(secret_key|known_data) can be exploited to produce hash(secret_key|known_data|appended_data) even ...
user173379's user avatar
7 votes
4 answers
543 views

Can I replace SHA-1 with SHA-512/160 to address Shambles?

The destination is software (within a remote trust boundary) that expects SHA-1 results. Would it be safer for the source (that's within my own trust boundary) to replace my SHA-1 computation at my ...
Invisigoth's user avatar

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