Cryptography Stack Exchange
Cryptography Stack Exchange

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.

SHA-1 is a cryptographic function that is no longer considered collision-resistant and should only be used for backward compatibility.

"Federal agencies should stop using SHA-1 ... as soon as practical, and must use the SHA-2 family of hash functions for these applications after 2010."

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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 coming). How easy is it to do so right now?
Hormoz
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Why initialize SHA1 with specific buffer?

SHA-1 is initialize with a specific buffer: h0 = 0x67452301 h1 = 0xEFCDAB89 h2 = 0x98BADCFE h3 = 0x10325476 h4 = 0xC3D2E1F0? Why?
juaninf
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Why can't they just fix SHA-1 if it's broken?

Presently 160 bits of hash block width seems to provide adequate security against brute force attacks. The recent developments concerning SHA-1 have reduced the effort to force collisions by 5 orders of magnitude according to the latest Wikipedia…
Paul Uszak
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Is Base64(SHA1(GUID)) still unique like the original GUID?

Basically what the title is; GUIDs are unique by design. If you run the GUID through SHA1 and then Base64 the hash, will the resulting string have the same guaranteed uniqueness as the GUID, or not?
John
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Calculating the amount of zero bits to be appended to the message

From FIPS 180-3 Suppose that the length of the message, $M$, is $l$ bits. Append the bit $1$ to the end of the message, followed by $k$ zero bits, where $k$ is the smallest, non-negative solution to the equation $l + 1 + k \equiv 448 \mod 512$ .…
Stijn
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How is it possible to detect "unknown SHA-1 cryptanalytic collision attacks given just a single file from a colliding file pair"?

The following description from http://shattered.it caught my eye: How do I detect this attack? You can use the online tool above to submit files and have them checked for a cryptanalytic collision attack on SHA-1. The code behind this was developed…
cmeeren
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Different implementations of SHA1, which one is correct?

I have noticed that different implementations of SHA1 give different results. As I'm currently programming my own SHA1 implementation (in MATLAB / GNU Octave), I wonder which one should I follow? There are several implementations of SHA1 in Rosetta…
nrz
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Changing SHA-1 constants an functions: Does it affect security?

I have been looking into the SHA-1 algorithm. I found that there are a set of functions and constants in the algorithm that have been standardized (section 5 of RFC 3174). If I want to use SHA-1, which I know is not advisable, does changing the…
Abdulahi
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SHA-1: number of possible inputs, number of possible outputs, how many inputs have the same output,

From Wikipedia I read SHA-1 function produces an output of 160 bits and expects a max message size of $2^{64}-1$ bits. Is that right? If I order all possible inputs I would produce $\approx 2^{2^{64}}$ different bit array inputs, right? Not sure at…
Eduard
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Are chosen-prefix collisions for SHA-1 a major threat?

GPG signing of Git commit tags relies on the collision resistance of SHA-1, which is weak. However, the attacker does not get to choose the prefix. How much does this translate to an actual vulnerability?
Demi
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Impact of Git's use of SHA-1?

Git uses SHA-1, and it is common to sign Git commit or tag hashes to authenticate a repo. Is this insecure now?
Demi
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Verifying identity using a sha-1 hash

I was reading http://blog.zorinaq.com/?e=74 which is about a Windows kernel developer. The developer proves that he is an actual developer by posting the SHA1 hash of a particular revision of a file. The actual hash values have been redacted, but I…
bobby
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Why do we have fixed output length in the algorithm SHA1

Why do we have fixed output length in the algorithm SHA1 . is there any explanation about that
Fuad Ahmad
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SHA1 multipart calculation

Is it possible to combine SHA1 digest values to get the SHA1 of the concatenated parts ? I know the "S1" SHA1 of "part 1" and the "S2" SHA1 of the "part 2" and I would like to know the SHA1 of the "part 1" concatenated with "part 2" calculated from…
Gabor Forgacs
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SHA-1 colission resistance proof

I'm searching Why the SHA-1 is collision resistance? Anybody could help me with the proof or say me where I can find this proof?
juaninf
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