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

According to some Hashcat benchmarks, a current Nvidia GPU can compute SHA-1 hashes at a rate of: NVIDIA GeForce RTX 3090 ~22.6×109 hashes per second NVIDIA GeForce RTX 3080 Ti ~21.7×109 hashes ...
• 7,759
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What is the new attack on SHA-1 "SHAttered" and how does it work?

In order to get a collision on a $n$ bit Random Oracle using the birthday paradox, one needs $\sqrt{\pi / 2} \cdot 2^{n/2}$ calls. In other words, in the case of the 160 output bits of SHA-1 the limit ...
• 10k
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How secure is SHA1? What are the chances of a real exploit?

Actually SHA-1 has been "officially insecure" for a longer time, since an attack method was published in 2011. The 2017 collisions was just the first known case of actually running the attack. But ...
• 87.5k
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Does "Shattered" actually show SHA-1-signed certificates are "unsafe"?

Yes, SHA1-signed certificates are unsafe. The SHAttered paper is instructive. From the introduction: The MD-SHA family of hash functions is the most well-known hash function family, which ...
Accepted

How are the functions used in cryptographic hash functions chosen?

The functions considered are binary functions of 3 bits to 1 bit (extended to bit vectors, that is bitwise functions). There are $2^{(2^3)}=256$ such functions. All the functions considered are ...
• 144k
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After Google's collision attack, is RSA-SHA1 signature still safe?

The answer is "not safe". But it is not safe, regardless of Google's attack. Before Google attacked, we knew that SHA-1 is not the best choice. Google found one collision based on some existing, ...
• 564

Does "Shattered" actually show SHA-1-signed certificates are "unsafe"?

The existence of the SHAttered result is not, I think, in itself a surprise: everyone knows that in theory you can create two streams of bytes that hash to the same value. Google's achievements (which ...
• 93.7k
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In 2020, SHA-1 practically broken in chosen-prefix collision (CP-collision). Can double SHA-1 hashing prevent CP-collision?

a. No such double hashing doesn't do a bit of good. Anything which collides after a single hash will definetly collide after a double hash. It preserves all collisions and adds new ones. We might ...
• 11.9k