First of all what are these functions?
Basically SHA-256, Scrypt are hashing algorithms (Not an encrypting algorithm ). Once you send a file or a text through this kind of hashing algorithm it generates a unique stream of bits. Let's say someone says"kitty94 is really cool", we can convert this string into a string using those mentioned algorithms, Once you change even a bit in that initial message the output of the function totally changes! ("kiity94 is a real fool"would give you a bitstream which is totally different from the previous output.) In other words, a hash algorithm does is mapping a given data set to an arbitrary size of data of fixed length.
Why do we need a hashing function for blockchain technology?
Blockchain technology (This is the backbone of the Bitcoin whereas Bitcoin is the biggest implementation of the Blockchain technology) is all about decentralized trust network which means each and every individual in the blockchain network (We call them miners) confirms each and every transaction unlike in a central hub.Actually, miners do isfindinga special numberto enter at the end of a certain number of crypto transactions (We call it a block). This special number gives some pre defined characteristic (For Bitcoin the condition is to generate an output with 30 zeros in the front after this block being input into SHA256 algorithm. Miners add different numbers to the end of the transaction set and send it through SHA256 function and check whether the output gives a bit stream with 30 zeros at the front. [Once you find a such number (We call it proof of work) Winner Winner Chicken Dinner!!])
SHA256 (Secure Hash Algorithm 256)
As Op already mentioned Bitcoin uses SHA256 which is far more complex and time-consuming than Scrypt. As the SHA256 is slow and thorough through the data it is considered as the more secure one among these two. Its advocates also say it's better for overall data security. Successful mining of coins using SHA-256 often requires hash rates at the gigahashes per second (GH/s) range (I have given a brief introduction at the end of the article ) or higher. this means it's generally more difficult for individual miners to use. Those who do often employ an ASIC or some other separate computing device set up to perform only mining tasks. Since some miners can't devote a machine?or at least an ASIC?to the task of mining, they often join mining pools. SHA256 pros and Cons can be listed as,
- More time Consuming.
- But Very Secure.
- Requires much higher hashrates - Miners can workaround this by joining each other and creating mining pools or by buying an ASIC (ApplicationSspecific Integrated Circuits, which were specially built for running the minng algorithm )
Scrypt
Since srypt is far more lightweight and less time consuming it has gained a quite popularity among upcoming cryptocurrencies. Running the Scrypt algorithm on your PC or Laptop won't try to drain your machine's resources as much as SHA256 does (We do not need you Mr. Expensive ASIC! ). Scrypt uses significantly less energy and computational power with respect to SHA256 (As its hashrates are in kilohashes per second). Though people argue that thissimpler system is more susceptible to security issues, since fast transaction turnaround times can mean the system is taking a less thorough look at the data. Its advocates point out, however, that hasn't as of yet presented a real-world problem.
- Simpler Algorithm
- Needs mush less resources than SHA256
- Though arguments are there, still there has not been a security breach or a reverse engineering happened yet
Now We have a rough idea about these two hashing algorithms, Still the original question remains, Which one do you think is best and why?
Although I am a newbie to the field and with no prior experience at all in the mining I thing Scrypt algorithm will get more popularity with time. Being able to run it on your personal laptop without the need to worry about really expensive hardware is a big plus point for as far as I concern. And also the harsh difficulty of the Bitcoin will be increased with the time (Present we need 30 zeros in the front and it is nearly a probability of 1 in a billion!!) With these reasons I think Scrypt will be the first choice of future coin developers!
Annex 1
Hashrates
KH/s: Kilohashes per second, or one thousand hash computations per second
MH/s: Megahashes per second, or one million hash computations per second
GH/s: Gigahashes per second, or one billion hash computations per second
TH/s: Terrahashes per second, or one trillion hash computations per second
PH/s: Petahashes per second, or one quadrillion hash computations per second
References:
https://www.coinpursuit.com/pages/bitcoin-altcoin-SHA-256-scrypt-mining-algorithms/
https://steemit.com/bitcoin/@malekalmsaddi/sha-256-vs-scrypt-mining
