Grøstl is a new cryptographic hash function designed in response to the Cryptographic Hash Algorithm Competition announced by NIST. Grøstl is one of the five finalists in the competition and it is a tweaked version of its predecessor called Grøstl-0, the original submission to the competition.

Grøstl is an iterated hash function, where the compression function is built from two fixed, large, different permutations. The design of Grøstl is transparent and based on principles very different from those used in the SHA-family.

The two permutations used are constructed using the wide trail design strategy, which makes it possible to give strong statements about the resistance of Grøstl against large classes of cryptanalytic attacks. Moreover, if these permutations are assumed to be ideal, there is a proof for the security of the hash function.

Grøstl is a byte-oriented SP-network which borrows components from the AES. The S-box used is identical to the one used in the block cipher AES and the diffusion layers are constructed in a similar manner to those of the AES. As a consequence, there is a very strong confusion and diffusion in Grøstl.

Grøstl is a so-called wide-pipe construction where the size of the internal state is significantly larger than the size of the output. This has the effect that all known, generic attacks on the hash function are made much more difficult.

Grøstl has good performance on a wide range of different platforms, and counter-measures against side-channel attacks are well-understood from similar work on the AES.

It was designed by a team of cryptographers from Technical University of Denmark (DTU) and TU Graz.

WHAT IS WITH THE GROESTL NAME?

The name “Grøstl” is a multilingual play-on-words, referring to an Austrian dish usually made of leftover potatoes and pork, cut into slices. These are roasted on a pan together with onions and butterfat. The dish is often seasoned with salt, pepper, marjoram, cumin, and parsley, and served with a fried egg or kraut (cabbage).

Hence, gröstl is somewhat similar to the American dish called hash. The letter ‘ö’ was replaced by ‘ø’, which is a letter in the Danish alphabet that is pronounced in the same way as ‘ö’. This way, the name, like the hash function itself, contains a mix of Austrian and Danish influences. The pronunciation of Grøstl may seem challenging. If you think so, then think of the letter ‘ø’ as the ‘i’ in “bird”. This letter is a so-called close-mid front rounded vowel.

I was able to ascertain that one of the original members that helped developed the Groestl hash, Praveen Gauravaram, was involved when creating Groestlcoin, and occasionally consults but not as much extensively as in the beginning.

What are the advantages and disadvantages of Groestl posted from Reddit post from constitutor, Shakesbeery:

Advantages:

⦁ Easy accessibility. Having a wallet on virtually every platform imaginable really makes GRS a coin of the masses. It’s easy to use and get started which is a huge plus for the continued longevity of the coin.

⦁ Total block size. The number of blocks is 105 million, 5x that of BTC. There is already discussion about how to keep track of smaller and smaller BTC transactions because as valuation increases, smaller amounts of BTC are needed. GRS won’t run into that problem for a much longer time, and possible even never.

⦁ Functionality. GRS offers all the key characteristics needed in a cryptocurrency to be viable.

Disadvantages:

⦁ Anonymity. Compared to Monero and ZCash, GRS doesn’t have the same potential anonymity that other coins do. In most cases, this is absolutely fine, but at the end of the day, there are a lot of people who want that feature, for good and for bad. It won’t hurt GRS much in the long run, but I think it will also slow down adoption a bit.

⦁ Speed. We’re seeing a ton of problems right now with other cryptocurrencies due to slow confirmations and transactions. SegWit is a good first step for GRS as it opens the door to other, faster protocol additions. Nevertheless, until a long-term solution for scalability is implemented, GRS will eventually run into the same issues.

⦁ Functionality. Yes, this is a pro and con. Although GRS is a great crypto as it is, it does not necessarily offer any innovative features like smart contracts, etc. using the blockchain itself. Right now, I believe GRS is poised to become a leader in feature implementation due to the possibilities SegWit offers, but until that happens, it’s still just a solid cryptocurrency among a handful of others.

ABOUT THE COIN:

- Is a cryptocurrency utilizing Proof of Work

- No ASIC currently exists for Groestl & it is unlikely that one will be developed for it anytime soon. GroestlCoin will be ASIC-free for the foreseeable future.

- Through these features GroestlCoin embodies the distributed & decentralized nature of Cryptocurrency. Anyone can mine effectively, with minimal resource consumption and nuisance.

- With the influx of ASICs we thought decentralized mining will soon be dead, with GroestlCoin it is reborn and taken to another level.

- The extra added value of Groestl is that the “richer advantage” (owning several GPU) is less interesting with Groestl; so fairer.

- Stands for democratization of currency and mining, the ability to send and receive money immediately anywhere in the world, to not pay expensive banking fees, and to transact in an environment that is secure and anonymous.

- Through an innovative algorithm, the Groestlcoin network consumes far less energy, maintains stronger security, and rewards miners in more sustainable ways than sha256, scrypt, x11 and x13 based coins.

- Grostl will be the new greener home of GPU miners as it offers greater hashing results with less energy and heat.

- We strive to make groestlcoin available to the masses. Innovative and user friendly, accessible for everyone. We highly value integrity and transparency. Digital currencies are the future and Groestlcoin will be one of the leaders in this revolution.

Here is the stated intended purpose of the Groestl Hash when it was originally created as found in whitepaper entitled, Groestl — A SHA-3 Candidate (page 4):

Overall goals for the hash

Here we state overall design goals for Grøstl

.

•Simplicity of analysis, hence, Grøstl is based on a small number of permutations instead of a block cipher (with many permutations).

•Provably secure construction (assuming ideal permutations).

•Well-known design principles underlying the permutations (again, allowing simple analysis, provable properties).

•No special preference for a particular platform or word size, and good performance on a very wide range of platforms.

•Side-channel resistance at little additional cost.

•Defining reduced variants for cryptanalysis is made straightforward.

•Prevention of length-extension attacks.

•Allow implementers to exploit parallelization within the compression function

ABOUT THE ALGORITHM:

- Is an iterated hash function, where the compression function is built from two fixed, large, different permutations. The design of Grøstl is transparent and based on principles very different from those used in the SHA-family. The two permutations used are constructed using the wide trail design strategy, which makes it possible to give strong statements about the resistance of Grøstl against large classes of cryptanalytic attacks. Moreover, if these permutations are assumed to be ideal, there is a proof for the security of the hash function.

- Can and is accelerated by the hardware AES support present in most modern Intel CPUs, which helps reduce the efficiency gap between a CPU and other implementations. Groestl (old GPU/CPU) — Groestl makes wide range of trade-offs between throughput, latency, and power consumption. Because of this, Groestl uses less power per hash than other algorithms. Due to the less complex hashing, Groestl performs well on older GPU’s as well as CPU’s. More info: http://www.groestl.info/Groestl.pdf

- Is the single most efficient algorithm for GPUs in the cryptocurrency market. It has been shown to have the lowest power consumption, heat and noise of recently released algorithms, allowing for a quieter and more effective mining environment.

- Is set to be the future of mining, Groestlcoin is proud to be the first to utilize this new efficient algorithm.

- Is a recently proposed cryptographic hash algorithm that has common structure and features with the Advanced Encryption Standard (AES). The objective of this paper is to present the design of a high-speed joint implementation of Grøstl and AES with minimal resources using a pipelining method. The advantage of this implementation is that it efficiently provides both cryptographic hash function and block cipher. The system is targeted to the Altera Cyclone IV FPGA. The paper presents a complete description of the design and implementation, as well as an analysis of the resulting synthesis and comparison to other proposed implementations of the Grøstl hash function.

- Is a byte-oriented SP-network which borrows components from the AES. The S-box (substitution-box) used is identical to the one used in the block cipher AES and the diffusion layers are constructed in a similar manner to those of the AES. Therefore, there is a very strong confusion and diffusion in Grøstl.

- Is a so-called wide-pipe construction where the size of the internal state is significantly larger than the size of the output. This has the effect that all known, generic attacks on the hash function are made much more difficult.

- Has good performance on a wide range of different platforms and counter-measures against side-channel attacks are well-understood from similar work on the AES.

ABOUT THE AES ACCELERATION:

The compression function f is based on a pair of 256- or 512-bit permutation functions P and Q, and is defined as:

f(h, m) = P(h ⊕ m) ⊕ Q(m) ⊕ h

The permutation functions P and Q are heavily based on the Rijndael (AES) block cipher, but operate on 8×8 or 8×16 arrays of bytes, rather than 4×4. Like AES, each round consists of four operations:

1. AddRoundKey (the Grøstl round keys are fixed, but differ between P and Q)

2. SubBytes (this uses the Rijndael S-box, allowing sharing with AES implementations)

3. ShiftBytes (expanded compared to AES, this also differs between P and Q, and 512- and 1024-bit versions)

4. MixColumns (using an 8×8 matrix rather than Rijndael’s 4×4)

Grøstl divides the input into blocks and iteratively computes hi = f(hi-1, mi). However, Grøstl maintains a hash state at least twice the size of the final output (512 or 1024 bits), which is only truncated at the end of hash computation.

GROESTL REVIEWS

In the NIST SHA-3 Cryptographic HASH Algorithm competition these were some of the concluding thoughts:

Grøstl

Grøstl relies on the eight-bit AES S-boxes for nonlinearity, and a Grøstl implementation can share circuitry with an AES implementation where both algorithms are needed [138, 142, 143]. Grøstl uses two very similar fixed permutations of either 512 or 1024 bits to build the round function for 256-bit and 512-bit variants, respectively. There are many possible design variations for Grøstl, more, perhaps, than any other finalist. Most designs take several times the area of SHA-2. However, Jungk [136] reported on a Grøstl-256 implementation that was folded eight ways on a Virtex-5 FPGA, with a size similar to a full SHA-256 implementation. This implementation gave about ¾ the throughput/area performance of the GMU SHA-2 implementation on the Virtex-5, and a somewhat better performance than Jungk’s folded Keccak implementation on the Virtex-5. While high-performance Grøstl implementations seem to be quite large and nearly always have a lower throughput/area ratio than SHA-2, Grøstl is generally better than BLAKE and Skein in throughput/area.

ABOUT THE COIN:

- Is a cryptocurrency utilizing Proof of Work

- No ASIC currently exists for Groestl & it is unlikely that one will be developed for it anytime soon. GroestlCoin will be ASIC-free for the foreseeable future.

- Through these features GroestlCoin embodies the distributed & decentralized nature of Cryptocurrency. Anyone can mine effectively, with minimal resource consumption and nuisance.

- With the influx of ASICs we thought decentralized mining will soon be dead, with GroestlCoin it is reborn and taken to another level.

- The extra added value of Groestl is that the “richer advantage” (owning several GPU) is less interesting with Groestl; so fairer.

- Stands for democratization of currency and mining, the ability to send and receive money immediately anywhere in the world, to not pay expensive banking fees, and to transact in an environment that is secure and anonymous.

- Through an innovative algorithm, the Groestlcoin network consumes far less energy, maintains stronger security, and rewards miners in more sustainable ways than sha256, scrypt, x11 and x13 based coins.

- Grostl will be the new greener home of GPU miners as it offers greater hashing results with less energy and heat.

- We strive to make groestlcoin available to the masses. Innovative and user friendly, accessible for everyone. We highly value integrity and transparency. Digital currencies are the future and Groestlcoin will be one of the leaders in this revolution.

Here is the stated intended purpose of the Groestl Hash when it was originally created as found in whitepaper entitled, Groestl — A SHA-3 Candidate (page 4):

Overall goals for the hash

Here we state overall design goals for Grøstl

•Simplicity of analysis, hence, Grøstl is based on a small number of permutations instead of a block cipher (with many permutations).

•Provably secure construction (assuming ideal permutations).

•Well-known design principles underlying the permutations (again, allowing simple analysis, provable properties).

•No special preference for a particular platform or word size, and good performance on a very wide range of platforms.

•Side-channel resistance at little additional cost.

•Defining reduced variants for cryptanalysis is made straightforward.

•Prevention of length-extension attacks.

•Allow implementers to exploit parallelization within the compression function

ABOUT THE ALGORITH:

- Is an iterated hash function, where the compression function is built from two fixed, large, different permutations. The design of Grøstl is transparent and based on principles very different from those used in the SHA-family. The two permutations used are constructed using the wide trail design strategy, which makes it possible to give strong statements about the resistance of Grøstl against large classes of cryptanalytic attacks. Moreover, if these permutations are assumed to be ideal, there is a proof for the security of the hash function.

- Can and is accelerated by the hardware AES support present in most modern Intel CPUs, which helps reduce the efficiency gap between a CPU and other implementations. Groestl (old GPU/CPU) — Groestl makes wide range of trade-offs between throughput, latency, and power consumption. Because of this, Groestl uses less power per hash than other algorithms. Due to the less complex hashing, Groestl performs well on older GPU’s as well as CPU’s. More info: http://www.groestl.info/Groestl.pdf

- Is the single most efficient algorithm for GPUs in the cryptocurrency market. It has been shown to have the lowest power consumption, heat and noise of recently released algorithms, allowing for a quieter and more effective mining environment.

- Is set to be the future of mining, Groestlcoin is proud to be the first to utilize this new efficient algorithm.

- Is a recently proposed cryptographic hash algorithm that has common structure and features with the Advanced Encryption Standard (AES). The objective of this paper is to present the design of a high-speed joint implementation of Grøstl and AES with minimal resources using a pipelining method. The advantage of this implementation is that it efficiently provides both cryptographic hash function and block cipher. The system is targeted to the Altera Cyclone IV FPGA. The paper presents a complete description of the design and implementation, as well as an analysis of the resulting synthesis and comparison to other proposed implementations of the Grøstl hash function.

- Is a byte-oriented SP-network which borrows components from the AES. The S-box (substitution-box) used is identical to the one used in the block cipher AES and the diffusion layers are constructed in a similar manner to those of the AES. Therefore, there is a very strong confusion and diffusion in Grøstl.

- Is a so-called wide-pipe construction where the size of the internal state is significantly larger than the size of the output. This has the effect that all known, generic attacks on the hash function are made much more difficult.

- Has good performance on a wide range of different platforms and counter-measures against side-channel attacks are well-understood from similar work on the AES.

ABOUT THE AES ACCELERATION:

The compression function f is based on a pair of 256- or 512-bit permutation functions P and Q, and is defined as:

f(h, m) = P(h ⊕ m) ⊕ Q(m) ⊕ h

The permutation functions P and Q are heavily based on the Rijndael (AES) block cipher, but operate on 8×8 or 8×16 arrays of bytes, rather than 4×4. Like AES, each round consists of four operations:

1. AddRoundKey (the Grøstl round keys are fixed, but differ between P and Q)

2. SubBytes (this uses the Rijndael S-box, allowing sharing with AES implementations)

3. ShiftBytes (expanded compared to AES, this also differs between P and Q, and 512- and 1024-bit versions)

4. MixColumns (using an 8×8 matrix rather than Rijndael’s 4×4)

Grøstl divides the input into blocks and iteratively computes hi = f(hi-1, mi). However, Grøstl maintains a hash state at least twice the size of the final output (512 or 1024 bits), which is only truncated at the end of hash computation.

GROESTL REVIEWS

In the NIST SHA-3 Cryptographic HASH Algorithm competition these were some of the concluding thoughts:

Grøstl

Grøstl relies on the eight-bit AES S-boxes for nonlinearity, and a Grøstl implementation can share circuitry with an AES implementation where both algorithms are needed [138, 142, 143]. Grøstl uses two very similar fixed permutations of either 512 or 1024 bits to build the round function for 256-bit and 512-bit variants, respectively. There are many possible design variations for Grøstl, more, perhaps, than any other finalist. Most designs take several times the area of SHA-2. However, Jungk [136] reported on a Grøstl-256 implementation that was folded eight ways on a Virtex-5 FPGA, with a size similar to a full SHA-256 implementation. This implementation gave about ¾ the throughput/area performance of the GMU SHA-2 implementation on the Virtex-5, and a somewhat better performance than Jungk’s folded Keccak implementation on the Virtex-5. While high-performance Grøstl implementations seem to be quite large and nearly always have a lower throughput/area ratio than SHA-2, Grøstl is generally better than BLAKE and Skein in throughput/area.

TEAM

Groestlcoin Founder & Advisor, groestlcoin.org/net/info owner, groestlcointalk.org owner:

Gruve_P — Igor from Latvia

Groestlcoin Android developer, Groestlcoin BlackBerry wallet in groestlcoin webwallet developer:

Hashengineering — Eric from USA

Groestlcoin-WPF, Groestlcoin coin-utile, Groestlcoin address utilty, Groestlcoin Armory and Groestlcoin Multisig developer:

Ufasoft — Sergey from Russia

IRC Groestlbot developer, Multigroestl Classic developer, Multigroestl HD developer, Groestlcoin Lite and Electrum-GRS Lite developer:

Xawksow — Kevin from Germany

Groestlcoin Electrum-GRS developers:

guruvan — Rob from USA Kefkius — Tyler from USA

Graphic designer:

hterw — from Belarus

iOS developer:

⦁ Quantumexplorer

Paper wallet developer and Groestlcoin forum creator:

Srcxxx — Dmitriy

Reddit Moderator and Reddit tippingbot developer:

Jwinterm — from USA

Groestlcoin Easyminer developer:

aceoyame — from USA

Facebook group admin:

Guidosuller — Luiginho from Brasil

Android price ticker and info developer:

Wiskunde — from Holland

Groestlcoin android miner developer:

⦁ Jesus Oliver

iOS GRS depot developer:

⦁ Carl Ambrosini from Italy

Cpu miner developer:

ig0tik3d

Groestlcoin forum admin, IRC tippingbot developer, Twitter tippingbot developer, QQ Group admin and IRC moderator:

jackielove4u — Jackie from Holland

CHALLENGES

There are two major challenges one immediate and another medium/long term:

⦁ Unpaid/Volunteer workforce

⦁ Mass user adoption

⦁ Marketing

⦁ Community

Unpaid/Volunteer workforce

I could easily attempt to find statistics to support my claim of the pros and or cons of an unpaid/volunteer workforce, however I will simply rely on common sense and sound judgement that an unpaid/volunteer workforce can only work so much until they will eventually have to pay their bills. We live in a society that, for the moment, is based on a monetary system that requires payment of goods and services. I do not see that changing in the foreseeable future. As such, contributions and donations of time, energy and in-directly money in the form of FREE goods and services can only take a project so far.

Eventually, an adoption of some type of paid model will have to take place. Even if it should adopt a social entrepreneur model like those embraced by Ashoka fellows. It will nevertheless require some paid contributors. The how, what, when, can be discussed at a later time, but I see this as potential roadblock to the success of this project. Not necessarily a huge obstacle but one that Groestl needs to factor into their overall strategy.

Mass User Adoption

Gaining mass user adoption is critical to any business endeavor. I stress the importance of having a clear marketing strategy and a team to execute on that strategy will significantly aid in gaining mass user adoption.

If we examine the supposed clear “leaders” in the crypto community each of them have some sort of marketing strategy albeit indirectly or directly or a combination of both. But the strategy exists. In addition, many have a spokesperson or evangelist that acts as the catalyst to being that bridge between the uber technical power user and the non-technical layman.

All businesses have four main categories:

Sales/Marketing- (S)

Operations- (O)

Accounting- (A)

Research/Development (R)

It is with all four components running smoothly like four wheels on a car that support (like four legs in a table) the business toward a bright and successful future.

Clearly Operations and Research/Development are being accomplished when it comes to Groestl but Accounting is a mystery and Sales/Marketing is next to null.

TREND ANALYSIS

The statistic presents data on the importance of various factors affecting the decision to purchase or use Bitcoins in the United States as of May 2014. During the survey, 61 percent of the respondents stated that the security of Bitcoin was a very important factor affecting the decision to purchase or use Bitcoins.

How important are various factors in your decision whether to purchase or use Bitcoins?

The statistic presents the total number of Bitcoins in circulation from fourth quarter of 2010 to first quarter of 2017. The number of Bitcoins has been growing since the creation of this virtual currency in 2009 and reached approximately 16.25 million in March 2017.

Number of Bitcoins in circulation worldwide from 4th quarter 2010 to 1st quarter 2017 (in millions)

This statistic presents the development of global currency reserves from 1995 to 2016. In 2016, global currency reserves amounted to approximately 10.79 trillion U.S. dollars.

Development of global currency reserves from 1995 to 2016 (in trillion U.S. dollars)

CONCLUSION

In conclusion, Groestlcoin has a very interesting offering and especially with some new future projects it could be a very exciting project.

They are, however, not without their challenges:

⦁ Unpaid workforce

⦁ Clear plan on mass user adoption

Both of these challenges are easily remedied. And as with all business endeavors execution will be paramount amongst everything they need to do. A strong team will help to achieve this and it is for this reason why I stress the importance of a full time paid work force.

Working on this part-time while trying to build a first-class crypto currency is not going to happen unless Groestl seriously takes the initiative to do so. I feel confident that the folks at Groestl will do so. They appear to be a talented group of people, with a good community built on strong technology.