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.

Filter by
Sorted by
Tagged with
1 vote
1 answer
78 views

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 ...
user avatar
73 votes
1 answer
42k 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 ...
user avatar
  • 647
2 votes
2 answers
100 views

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?
user avatar
  • 23
2 votes
1 answer
330 views

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($§&...
user avatar
  • 23
1 vote
1 answer
104 views

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 <...
user avatar
  • 15
1 vote
1 answer
94 views

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?
user avatar
4 votes
1 answer
620 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): ...
user avatar
  • 153
2 votes
1 answer
76 views

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 ...
user avatar
1 vote
1 answer
105 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 ...
user avatar
  • 13
0 votes
2 answers
167 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 ...
user avatar
0 votes
1 answer
131 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 ...
user avatar
0 votes
0 answers
47 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 ...
user avatar
2 votes
0 answers
59 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 ...
user avatar
  • 121
3 votes
2 answers
1k 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 ...
user avatar
0 votes
1 answer
180 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-...
user avatar
  • 13
-2 votes
2 answers
104 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 ...
user avatar
2 votes
1 answer
181 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 ...
user avatar
1 vote
1 answer
67 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 ...
user avatar
1 vote
1 answer
105 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 ...
user avatar
  • 113
2 votes
1 answer
90 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 ...
user avatar
  • 123
2 votes
0 answers
70 views

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), ...
user avatar
  • 3,057
1 vote
0 answers
43 views

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 ...
user avatar
  • 111
9 votes
1 answer
1k 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 ...
user avatar
2 votes
2 answers
439 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, ...
user avatar
  • 21
2 votes
1 answer
108 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, ...
user avatar
4 votes
2 answers
608 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 ...
user avatar
  • 155
1 vote
1 answer
366 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 ...
user avatar
8 votes
3 answers
6k 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?
user avatar
4 votes
2 answers
819 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 ...
user avatar
  • 151
0 votes
0 answers
61 views

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,...
user avatar
0 votes
0 answers
61 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 ...
user avatar
  • 13
-1 votes
1 answer
162 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 ...
user avatar
1 vote
0 answers
172 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 ...
user avatar
1 vote
2 answers
196 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 ...
user avatar
  • 155
1 vote
1 answer
252 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 ...
user avatar
  • 13
1 vote
1 answer
2k 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 ...
user avatar
7 votes
4 answers
401 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 ...
user avatar
2 votes
1 answer
3k views

What is the use of encoding a hash output?

In many applications, the MD5 algorithm is used which produces a 128-bit output which is represented as a sequence of 32 hexadecimal digits. This output is further encoded using a base62 or base64 ...
user avatar
16 votes
1 answer
12k views

In 2020, SHA-1 practically broken in chosen-prefix collision (CP-collision). Can double SHA-1 hashing prevent CP-collision?

In a recent study SHA-1 is a Shambles - First Chosen-Prefix Collision on SHA-1 and Application to the PGP Web of Trust by Gaëtan Leurent and Thomas Peyrin. 2020, they showed the first practical chosen-...
user avatar
  • 43.4k
5 votes
2 answers
318 views

"One-Wayness" of SHA 1

I recently started learning about Hash Functions for my first time, and I've gone through and have tried to understand the SHA1 process. Brilliant does an excellent job of explaining it step by step. ...
user avatar
6 votes
1 answer
307 views

Do a 160-bit SHA-1 hash and a 160-bit slice of a SHA-256 hash have the same strength in terms of collision-free?

Take OpenPGP fingerprint for example. If the 40-digit hex standard remains unchanged, would it be helpful to upgrade SHA-1 to SHA-256 (but only taking the last 160 bits), in terms of reducing the risk ...
user avatar
0 votes
1 answer
89 views

Equal hashes for different messages when doing key length extension attack sha1

I was doing the cryptopals challenge 29, and I found something weird. When I try to create a forged hash for a forged message I get always the same hash for different forged messages. ...
user avatar
3 votes
3 answers
2k views

Is using RSA with SHA-1 considered as secure as HMAC-SHA-1?

I know SHA-1 hashing is regarded insecure. HMAC-SHA-1 is still regarded secure as this is an encryption process with symmetric key of the hash produced by SHA-1. So signing using RSA with a key size ...
user avatar
  • 183
0 votes
1 answer
269 views

How to use SHA-1 as a PRNG?

Is there any special parameters for using SHA-1 for generating pseudo-random numbers? What are the differences between SHA-1 as a PRNG and original SHA-1?
user avatar
0 votes
3 answers
2k views

CRC32 catches errors, but then what's the point of SHA?

If crc or CRC32 is specially designed to catch errors, then what's the point of SHA or md4-5 or any other hashing function? What I did was, I had a 190 mb png file (rendered in 16k resolution with ...
user avatar
5 votes
2 answers
1k views

Is it feasible to get a hash collision for CRC32, MD-5 and SHA-1 on one file?

I'm aware that individually, each has its weaknesses (especially CRC32), but is it feasible that a file could be created to falsely match all three?
user avatar
  • 161
4 votes
1 answer
65 views

Recover secret SHA-1 constants given Oracle

There's a black box that's basically SHA-1, except that the constants (h0, h1,...,h4) are secret. We can pass it arbitrary inputs and get the corresponding outputs. Given this, is it possible to ...
user avatar
  • 197
0 votes
0 answers
110 views

Which SHA-1 attacks apply to TOTP tokens? [duplicate]

Update: it's actually hmac(secret, time). I'll leave the post as-is, in case someone is ever looking for the hash(secret+time) ...
user avatar
  • 1,386
7 votes
2 answers
4k views

Does a hash function have a Upper bound on input length?

I came across this Answer stating (just a line from the answer):- The input space is "infinite" and thus it has an infinite amount of values that will collide into a single hash And in the ...
user avatar
9 votes
3 answers
5k views

How many bits in the resultant hash will change, if the x bits are changed in its the original input?

I came across a question stating: We have a message consisting of 10,000 characters. After computing its message digest using SHA-1, we decide to change the last 19 characters in the original ...
user avatar

1
2 3 4 5 6