Design And Implementation Of Keccak Hash Function For Cryptography

Written by Suzi on . Posted in Crypto News

keccak hash

In the well-known hash function MD5, for instance, each lap of the compression function takes 128 bits of internal state information and 512 bits of the file you want to hash. It munges and compresses these 640 bits of input into a 128-bit output, which becomes the new internal hash state. This pertains to a highly-adaptable cryptographic or hash function developed at the aim of producing tighter and heightened security for blockchains. The Keccak is a step-up from the likes of the more industry-recognized and accepted hash functions such as the SHA-1 and SHA-2.

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A US government agency has selected cryptographic hash function Keccak as the new official SHA-3 algorithm. Eventually CPUs will come with hashing functions when they become so popular, so that will again significantly reduce the performance penalty. Unless something has changed for the better, I question whether SHA-3 offers any security benefits over SHA-512. The first change proposed is to the padding algorithm used to break the arbitrary-sized input into blocks to feed to the sponge rounds. The original submission proposed a simple padding algorithm similar to the Damgård–Merkle padding used by earlier hashes.

Let’s review the most widely used cryptographic hash functions . This means you can’t reconstruct input data from the hash output, nor can you change input data without changing the hash. You also won’t find any other data with the same hash or any two sets of data with the same hash. ding a sequential operating mode, there is also a tree mode that allows large input messages to be hashed in parallel.

Pysha3 0 1

Of course, ETC could use any other algorithm that’s not adopted in the market to become the majority algorithm in that respective PoW, but there are some reasons Keccak-256 stands out. 51% attacks, or majority attacks, are a part of PoW, but when you’re a minority chain you lose the security assumptions of PoW consensus. ETC is not only vulnerable to the majority ETH chain, but it is also vulnerable to other networks tailored to general-purpose hardware that can be turned onto ETC. Programmable Proof of Work , originally called Progressive Proof of Work, was a PoW algorithm proposed on ETH to close the efficiency gap between ASICs and GPUs . While closing gaps and being progressive is marketable, the proposal was a political debate, not a technical one because ProgPoW would have simply started a new cycle of prolonging ASICs to buy time for the Ethereum PoS agenda. However, ASIC resistance is built on a false premise that puts equity theatre at face-value but doesn’t hold up in practice. You’ll always have computer chips that can be made to do tasks faster, more secure, and more efficiently. Ethash requires chips on top of memory requirements to mine. Ethereum launched with the Ethash PoW algorithm which is based on Keccak-256 with the additional features of Dagger and Hashimoto .

keccak hash

It produces a 160-bit message digest, which if cryptographically perfectly secure means that it would take a brute force guessing attack 2159 tries on average to crack a hash. Even in today’s world of very fast cloud computers, 2159 tries is considered non-trivial to create a useful attack. Non-trivial is the term crypto professionals use when they mean almost impossible, if not impossible, given current understanding of math and physics. Cryptographic hashes provide integrity, but do not provide authenticity or confidentiality. Hash functions are one part of the cryptographic ecosystem, alongside other primitives like ciphers and MACs. If considering this library for the purpose of protecting passwords, you may actually be looking for a key derivation function, which can provide much better security guarantees for this use case. To make it clearer that Ethereum uses KECCAK-256 instead of the NIST standardized SHA-3 hash function, Solidity 0.4.3 has introduced keccak256. These functions differ from ParallelHash, the FIPS standardized Keccak-based parallelizable hash function, with regard to the parallelism, in that they are faster than ParallelHash for small message sizes. Although part of the same series of standards, SHA-3 is internally different from the MD5-like structure of SHA-1 and SHA-2.


KangarooTwelve and MarsupilamiFourteen are Extendable-Output Functions, similar to SHAKE, therefore they generate closely related output for a common message with different output length . Such property is not exhibited by hash functions such as SHA-3 or ParallelHash . The unused “capacity” c should be twice the desired resistance to collision or preimage attacks. The creators of the Keccak algorithms and the SHA-3 functions suggest using the faster function KangarooTwelve with adjusted parameters and a new tree hashing mode without extra overhead for small message sizes. The second part of the keccak hash function is the “sponge construction” that is used to take this finite-sized random permutation and make a cryptographic hash on arbitrary-sized inputs. There are strong security proofs on the sponge function, assuming the permutation at its core is truly random. I personally don’t see any advantage to having a general purpose hash function with less than 256 bits of output.

  • In October 2012, Keccak won the NIST hash function competition, and is proposed as the SHA-3 standard.
  • To obtain a compact design, serialized data processing principles are exploited together with algorithm-specific optimizations.
  • The design requires only 2.52K gates with a throughput of 8 Kbps at 100 KHz system clock based on 0.13-μm CMOS standard cell library.
  • Although any choice of capacity is valid, we highlighted 5 values for the capacity, namely 448, 512, 576, 768 and 1024 bits.
  • The new proposal keeps only one of these 5 values , and introduces a new one, 256.
  • is a family of hash functions tunable by the size of its internal state and by a security parameter called capacity.

is a family of hash functions tunable by the size of its internal state and by a security parameter called capacity. Although any choice of capacity is valid, we highlighted 5 values for the capacity, namely 448, 512, 576, 768 and 1024 bits. The new proposal keeps only one of these 5 values , and introduces a new one, 256. In October 2012, Keccak won the NIST hash function competition, and is proposed as the SHA-3 standard. It should be noted that it is not replacement SHA-2, which is currently a secure methods. Overall Keccak uses the sponge construction where the message blocks are XORed into the initial bits of the state, and then invertibly permuted. InstanceDescriptioncSHAKE128A version of SHAKE supporting explicit domain separation via customization parameters.cSHAKE256KMAC128A keyed hash function based on Keccak. Can also be used without a key as a regular hash function.KMAC256KMACXOF128KMACXOF256TupleHash128A function for hashing tuples of strings. Unlike KangarooTwelve, does not use reduced-round Keccak.ParallelHash256ParallelHashXOF128ParallelHashXOF256• X is the main input bit string. Last month Schneier called for the competition to be left open, arguing the longer-bit SHA-2 variants remain secure and that the wannabe SHA-3 replacements do not offer much improvement in terms of speed and security.


In January 2011 (with NIST document SP A), SHA-2 became the new recommended hashing standard. SHA-2, is often called the SHA-2 family of hashes, because it contains many different-length hashes, including 224-bit, 256-bit, 384-bit, and 512-bit digests . You can’t determine which SHA-2 bit length someone is using based on the name alone, but the most popular one is 256-bits by a large margin. SHA-1 was designed by the United States National Security Agency and published by National Institute of Standards and Technology as a federal standard (FIPS Pub 180-1) in 1995.

keccak hash

Some others showed an alternative scheme that allows extension to tree hashing, a useful feature that other SHA-3 submissions provided. What possible use case could see a 30% impact to a 30% more expensive hash function? What sort of user is doing enough hashes that the hash function calculation time is a noticeable fraction of their day? Even in the case of a hardware how to buy gnt smartcard, how many times is a hardware security device used per day? It seems like NIST is solving a problem that nobody has. This would be one thing if it was random posters on reddit. But serious cryptographers discussing this issue seem to be focusing less on cryptographic analysis than they are in looking for the NSA hiding behind every tree and under every rock.


The fact that the likely cause, and certainly the content, of the debate here is centered around some conspiracy theory is at least a little troubling to me. At the end of the day, I agree with the idea that maybe NIST should just standardize Keccak as-is …but if the reason for doing so involves current events, I think they’d be doing it for the wrong reasons. As I’ve also said befor I would advise people to have the other NIST competition finalists in a “ready to run” state in your own framework. Neither AES or SHA-3 winners are the most secure or conservative designs so were always a compromise, and if for no other reason than prudence having a ready to run fallback is good kyc acronym engineering practice. That said, I DO think there is a reasonable point to be made against changing SHA3. The changed pre-image security level would be below the level of the original requirement as far as I understand. A different initial requirement may have changed some of the other submissions. A perceived lack of “fairness” in the process might make it harder for NIST next time they want to run a competition. And ultimately, reasonable or not, it might be in the best interests of everyone if NIST mollified the folks concerned that any changes could be a backdoor. I believe at this point that they’re going to go out of their way to sink SHA3 if they don’t get their way.

What are two common hash functions?

The most common hash functions used in digital forensics are Message Digest 5 (MD5), and Secure Hashing Algorithm (SHA) 1 and 2.

It will need up to 1600 bytes of RAM for the hash state, but no lookup tables. Keccak can also perform keyed hashing, by setting the initial state by priming the hash with the key. The algorithm is simple and small, perfect for embedded systems. While SHA-3 presents the latest secure hash algorithm available, SHA-2 remains viable for some applications. To do this first step, the host requests the ROM ID from hash the slave and inputs it, along with its own securely stored system secret and some compute data, into its own SHA-3 engine. Next, the engine computes a SHA-3 hash-based MAC that’s equal to the unique secret stored in the authentication IC. Once it securely derives the unique secret in the slave IC, the host controller can perform various bidirectional authentication functions with the authentication IC.

The NIST gives off a bad smell when at the 11th hour the bit strength is basically cut in half. I do understand that there 256 bit strength and then there very strong 256 bit strength due to actual implementation. Given mathematics and all things being equal, 512 bit strength is much higher than 256 bit strength . Unless you were a User that spent your money building a gigantic computer to brute force search for hash collisions for some nefarious purpose. Silent Circle’s rumored embrace of Twofish over AES is a silly move, if you ask me. Abandoning well over a decade of dedicated cryptographic analysis over some vague, and unsupported, conspiracy fears seems like a ridiculous tradeoff to me. Like I said, I think the strongest argument for leaving Keccak alone is that changing ANYTHING after the competition is over has, at the very least, fairness issues. But I think those issues should apply regardless of the situation.

keccak hash

For example the 128-bit version will produce a hash value is 32 hex characters. NIST published the new standard on 5 August and which beat off competition from BLAKE (Aumasson et al.), Grøstl , JH , and Skein (Schneier et al.). It should be noted that it does not follow the FIPS-202 based standard (a.k.a SHA-3), which was finalized in August 2015. Sections (mentioning “tree mode”), 6.2 (“other features”, mentioning authenticated encryption), and 7 (saying “extras” may be standardized in the future). 155.50Optimized implementation using AVX-512VL (i.e. from OpenSSL, running on Skylake-X CPUs) of SHA3-256 do achieve about 6.4 cycles per byte for large messages, and about 7.8 cycles per byte when using AVX2 on Skylake CPUs. Performance on other x86, Power and ARM CPUs depending on instructions used, and exact CPU model varies from about 8 to 15 cycles per byte, with some older x86 CPUs up to 25–40 cycles per byte. This proposal was implemented in the final release standard in August 2015. The rate r was increased to the security limit, rather than rounding down to the nearest power of 2.

BLAKE2s, optimized for 8- to 32-bit platforms and produces digests of any size between 1 and 32 bytes.¶The canonical name of this hash, always lowercase and always suitable as a parameter to new() to create another hash of this type. Case Studies Through use in games, databases, sensors, VoIP application, and more there is over 1 Billion copies of wolfSSL products in production environments today. instead of RIPEMD, because they are more stronger than RIPEMD, due to higher bit length and less chance for collisions. is widely used in practice, while the other variations like RIPEMD-128, RIPEMD-256 and RIPEMD-320 are not popular and have disputable security strengths. and is published as official recommended crypto standard in the United States.

This work focuses on the exploration and analysis of the Keccak tree hashing mode on a GPU platform. Based on the implementation, there are core features of the GPU that could be used to accelerate the time it takes to complete a hash due to the massively parallel architecture of the device. In addition to analyzing the speed of the algorithm, the underlying hardware is profiled to identify the bottlenecks that limited the hash speed. The results of this work show that tree hashing can hash data at rates of up to 3 google play branding guidelines GB/s for the fixed size tree mode. On a 3.40 GHz CPU, this is the equivalent of 1.03 cycles per byte, more than six times faster than a sequential implementation for a very large input. For the variable size tree mode, the throughput was 500 MB/s. Based on the performance analysis, modification of the input rate of the Keccak sponge resulted in a negligible change to the overall speed. As a result of the hardware profiling, the register and L1 cache usage in the GPU was a major bottleneck to the overall throughput.

You, your co-workers, and your vendors need to become crypto-agile. Software-wise, SHA-1 is three times faster and SHA-512 is two times faster than SHA-3 on Intel CPUs. Because our CPUs are getting faster and faster, it wouldn’t be long before the increase in time wouldn’t be noticeable at all. Plus, the authors of the hash selected as SHA-3 have told the NSA/NIST a few ways to make it significantly faster in software. By early 2017, a large percentage of customers had migrated to SHA-2. On February 23, 2017, Google announced a successful, real-life, SHA-1 collision attack, demonstrated by presenting two different PDF files with the same SHA-1 hash. The NIST standard was only published on August 2015, while Monero went live on 18 April 2014. For that reason original Keccak-256 gives in a different hash value than NIST SHA3-256. The module is a standalone version of my SHA-3 module from Python 3.6 .

BLAKE2 can be securely used in prefix-MAC mode thanks to the indifferentiability property inherited from BLAKE. then the digest size of the hash algorithm hash_name is used, e.g. 64 for SHA-512. The string hash_name is the desired name of the hash digest algorithm for HMAC, e.g. ‘sha1’ or ‘sha256’. Applications and libraries should limit password to a sensible length (e.g. 1024). salt should be about 16 or more bytes from a proper source, e.g. os.urandom(). hashlib.algorithms_available¶A keccak hash set containing the names of the hash algorithms that are available in the running Python interpreter. The same algorithm may appear multiple times in this set under different names . hashlib.algorithms_guaranteed¶A set containing the names of the hash algorithms guaranteed to be supported by this module on all platforms. Note that ‘md5’ is in this list despite some upstream vendors offering an odd “FIPS compliant” Python build that excludes it.