Questions tagged [sha-3]

SHA-3, also known as Keccak, is a cryptographic hash function standardized by NIST as a new alternative to the SHA-2 hash function family.

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53 views

SHA3 hexadecimal paddig odd length string

Section B2 of FIPS-202 specification describes the Hexadecimal Form of Padding Bits which is basically the translation of the bit padding 0110*1. However at the beginning they suppose that the message ...
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1answer
59 views

SHA3-512 similar message digest

How is it possible to find a similar message-digest for SHA3-512 for the first 80 bits or so? There was a Q/A on this site where the answer stated that 80 bits that $2^{42}$ computations are required. ...
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Are there any crypto hash implementation beyond 512 bits of output?

My question is this: Are there any crypto hash implementations beyond 512 bits of output? Could you give me the link? Thank you so much for your time. Greetings.
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Are the common hash algorithms already dead? [closed]

I have one honestly question: How can we are so confident with the use of the common hash algorithms (nowadays there are so many pages with cracking tools: crackstation, gpuhash, etc) ? Are we lost ...
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3answers
108 views

Using sha3 as a deterministic source of psuedo-random bytes for xor encryption

The following code generates a deterministic stream of pseudo-random bytes, using SHA3. ...
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2answers
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Is it possible to create a ciphersuite for TLS 1.3 using only the Keccak-sponge/duplex?

Now that Keccak has been chosen as SHA-3 we see that there have been defined quite a few related modes, including authenticated cipher modes, the KMAC message authentication mode, XOF's and whatnot. ...
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1answer
46 views

Does hashing PII in logs provide any real security?

I have PII in my logs that I would like to replace with hashes (e.g. sha3-256(salt + email)). The idea is that I can always go back to my logs and find all the log ...
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0answers
29 views

How are the Keccak rate and capacity bits determined at the beginning stage of the algorithm?

I'm learning about Keccak and am trying to understand more about the rate and capacity; specifically, how they are determined at ...
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1answer
31 views

How to use Botan to verify a web3 wallet/password?

The specification here seems quite clear, but unfortunately I'm still doing something wrong... I have this (single small c++ file) repository which very straightforwardly follows the password/wallet ...
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2answers
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How does KECCAK operate on a state array filled with zeros?

Im trying to implement a sponge in Java. The state starts out as an empty 200 byte array of all zeros. In the KMAC samples document from NIST, the following happens: (black line is a pdf page break) ...
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1answer
109 views

Why HAIFA and sponge constructions are not prone to length extension attacks?

I was writing in a document about the flaws of the MD construction which pushed cryptographers to create different and more robust constructions. However, I don't know why HAIFA and Sponge ...
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2answers
438 views

What is the sponge construction in simple terms?

I suggested to my client to use SHA3 instead of SHA2. I know that SHA3 is based on Keccak algorithm which won the NIST's competition. I want to explain the structure of sponge functions in very simple ...
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48 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,...
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143 views

Padding of SHA-3

SHA-3 uses Padding, so the original message has a certain length. In the case of SHA-3-512 each block has the size of 576, so any message must be padded, such that it is a multiple of the blocksize ...
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1answer
75 views

Layman understanding of SHAKE128 XOF

Need some help. I am not versed in hashing and just started programming with PHP and currently need to hash some strings but required it to be unique. Found that OpenSSL can hash with SHAKE128 but ...
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2answers
134 views

Safest alternative for hashing credit card numbers to use the hash as fingerprint?

Same question asked here in 2014 but since a lot has changed since then, I would like to get feedback from experts on the latest best practices. The problem Our requirement is to provide the ...
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1answer
59 views

How does re-hashing affects security strength?

I am currently saving hashed passwords for my website. Passwords are salted and then hashed using SHA3-512. I understand the security level of SHA3-512, as it is for all Keccak algorithms, is half the ...
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142 views

SHA-3 for Integrity

We used to use CRCs to check the integrity of files. For safety analysis we could associate a probability for detecting a corrupted bit in a large file. Now we are using an RSA Signed SHA-3 hash for ...
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1answer
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Recommended Shake256 digest size for KMAC based HKDF

On the wiki page for HKDF, in the Python Implementation, there is a hash_length variable for the ...
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2answers
158 views

SHA3 the Left & Right Encode Functions

In this paper (Section 2.3.1, Pg.5), I came across the left_encode and right_encode functions, and I have some questions about ...
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2answers
187 views

Split hash for 2 keys

These are the steps: Hash ECDH shared secret with SHA3-512 Concatenate odd bytes and rehash with SHA3-512 for AES-256 key Concatenate even bytes and rehash with SHA3-512 for KMAC key Is this key ...
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1answer
68 views

Hashing high entropy key into AES format

If I have a high entropy key (ECDHE shared secret), what type of hash should I use to format this into an AES-256 key? Is Sha256 or Sha3_256 sufficient to maintain entropy or do I need to use a KDF (...
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1answer
156 views

SHA3-512 troubleshooting - is there a worked example for hashing the “zero-length string”?

(I wondered if this question should be asked on StackOverflow instead because it's a programming related issue, but it's bound to the intricacies of SHA3, which I figured was a better fit for Crypto....
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1answer
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How to interpret a specific mathematical notation in “FIPS 202” (SHA-3 / Keccak)

tl;dr What does "d <= |Z|" mean in the context of bit array manipulations? As a learning exercise I'm working on an implementation of SHA-3. I am not a cryptography specialist in any way but I ...
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3answers
2k views

SHA3-255, one bit less

I need a SHA3-255 or 511. What if I simply truncate a standard SHA3-256 or 512? Apart from the doubled probability of hash collision, are there any other things I should be aware of? I could also ...
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2answers
237 views

Is there an input length range for SHAKE128 hash function?

For SHAKE128 hash function in SHA3VS document, I find this paragraph: Therefore, for testing SHAKE128, (168*2)+1) = 337 unpredictable messages will be generated with lengths from 0 to 337 336 ...
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Why isn’t SHA-3 in wider use?

SHA-3 was released by NIST just over 4 years ago this week. In my experience it does not seem to be as widely used as I might have expected. I see SHA-2 and even SHA-1 more often. What are your ...
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1answer
267 views

Where do the constants for SHA-1/2/3 come from?

My request is: I need to know the source of constants (shift constants, IV, or S-Box) for the following algorithms: SHA-1 SHA-2 (all sizes) SHA-3 Examples: BLOWFISH uses the hexadecimal ...
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2answers
2k views

SHAKE-128/256 or SHA3-256/512

Would it be better to use SHAKE-128/256 or SHA3-256/512? In what situation should I chose one over the other?
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0answers
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How padding works on SHA-3? [duplicate]

I'm studying SHA-3 and I dont understand quite a bit how the padding 10*1 works. Can someone explain me step by step how is it work? Also I know that on SHA3-512 r is 576. On the sponge construction ...
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2answers
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What is the difference between SHA-3 and SHA-256?

I am new about cryptography, I learned that SHA-3 (Secure Hash Algorithm 3) is the latest member of the Secure Hash Algorithm family of standards, released by NIST....
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1answer
680 views

SHA-3 Step by step?

Can somebody explain me or give me a link of a step by step SHA-3 explanation it has been really hard for me to undesrtand it. I would love to see an explanation since it's input untill the digest is ...
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1answer
80 views

What does the minimal number of round of “nr” use Keccak to avoid “collision attack”?

What does the minimal number of round of "nr" use Keccak to avoid collision attack? $$nr = 12+2L$$
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1answer
103 views

OAEP security with variable length hash function

I'm implementing a hobby cryptosystem for fun and to increase my knowledge on the subject, and I was wondering if the OAEP construct was still sufficient as an all-or-nothing-transform if variable ...
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2answers
490 views

Integrity check of a binary firmware file with hash function

I need to provide a mechanism that it is possible to verify the integrity of a firmware image flashed on an embedded system. The procedure should be, that if someone has doubt on the firmware’s ...
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2answers
343 views

What do the security definitions of SHA-3 mean, quantitatively?

In the SHA-3 standard (page 31) the security of SHA-3 is defined quantitatively, for example, they are saying SHA3-256 provides 256 bits of preimage resistance. How is this number of bits to be ...
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1answer
252 views

What is the minimum message length to obtain the full potential of a hash?

Suppose I want to commit to a uniformly picked nonce of fixed length $n$ bits without revealing the nonce, so I use a secure hash function $H$ mapping messages to digests of length $d$ bits. Suppose $...
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1answer
283 views

Computational Complexity of SHA-3 (SHAKE128)

Please, I got the question "what is the computational complexity of SHA-3 (SHAKE128)"? What does that mean and how can I calculate that?? *I am using SHA-3 (SHAKE128) in my mechanism to hash fix ...
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2answers
381 views

Intuition for SHA3 sponge construction

I would like to get some intuition on the security of the sponge construction. I'm referring to this diagram and notation. Let's consider the case where we have don't apply $f$ in the squeezing ...
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1answer
330 views

How long would it take to crack a double hash if salt and final hash are public?

I have a hash of a file $H_1$ and then I add salt and rehash it: $H_2$. I make my $H_2$ and salt public and I use my $H_1$ as a password. How long would it take for this to be cracked with someone ...
4
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1answer
279 views

What does Keccak being “efficiently invertible” mean?

Reading through Wikipedia, I saw this: It has been shown that the Merkle–Damgård construction, as used by SHA-2, is collapsing and, by consequence, quantum collision-resistant, but for the sponge ...
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1answer
4k views

Why is SHA-3 robust against Length-Extension Attacks?

If a length extension attack can occur because of $H(\text{K}\mathbin\|\text{Message})$, what changed in SHA-3 from SHA-2 that prevents this from occurring?
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1answer
303 views

rotation offsets for KECCAK-$f$[800]

So let's say you're trying to do SHA3-224. If you're on a 64-bit machine you'd presumably use KECCAK-$f$[1600]. In-so-far as I understand it'd have the following parameters: Rate: 448 (2*224) ...
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1answer
309 views

why was padding changed when keccak became sha3?

In the original Keccak you would pad by adding a 1 bit proceeded by a predetermined amount of 0 bits and then another 1 bit. When Keccak was standardized to sha3 the padding was changed. It was then (...
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2answers
432 views

mapping a 256 bit random number to a 3 bit number

I am making a 2 player dice game that runs for n rounds. To create random dice roles im using a concept a understood from randao. each user generates n sha3 hashes recursively of a random seed : e.g. ...
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2answers
1k views

Benchmark (hash rate) for SHA-3 (SHAKE128)

To estimate the time for brute-force attack we need to compute keyspace size divided by hash rate, where the hash rate (hash/second) varies depending on the computer's capabilities. The website https:...
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1answer
267 views

Benchmark for SHA-3 (Shake128) [duplicate]

I am trying to find the average of hash rate (benchmark) for SHA-3(Shake128) for a normal and supercomputer in order to estimate the brute-force attack which I can get if from ( keyspace / hash rate )....
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1answer
472 views

How secure is using a hash function as Key Derivation Function?

I am developing a personal project and I have the following need: given a randomly generated seed (with enough entropy) I need to generate a number $x$ of Ed25519 key pairs. These key pairs are not ...
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0answers
48 views

Hash Function SHA-3 [duplicate]

I would like to discuss the minimum input of hash function to consider strong (e.g Shack128 (SHA-3)). I have a mechanism based on SHA-3, but the input is just 40-bit, some friends told me 40-bit input ...
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0answers
702 views

SHA3 hardware implementation [closed]

I am studying SHA3 in order to create a hardware implementation, preferably in verilog. I have downloaded VHDL reference implementation from https://keccak.team/hardware.html. The code is great, and ...