Producing a Block Chain in the Crystal Language

The Crystal programming language is a robust, statically-typed, object-oriented language that is well-suited for developing cryptocurrencies as it can proficiently manage the complex mathematical computations involved. This tutorial is designed to furnish an all-inclusive manual for creating a blockchain using the Crystal programming language. However, prior to the start of the tutorial, it is crucial to grasp the fundamentals of what a blockchain entails.

Let us define what a blockchain is.

A blockchain is a digital ledger that is distributed and shared across a network of several computers. It furnishes an unchangeable record of information that is stored permanently, thereby making it a prevalent option among cryptocurrency networks due to its robust security and decentralization of financial transactions. Some notable examples of virtual currencies that are based on blockchain technology are Bitcoin and a multitude of others.

Blockchain technology facilitates the creation of trust in the absence of a trusted third-party. Instead of relying on a traditional database that stores records in one place, blockchain technology structures data into blocks, each of which accommodates a predefined number of records. This innovative approach to data storage and management has the potential to revamp the way we interact with one another by removing the requirement for centralized intermediaries.

Blockchain technology utilizes a chain-shaped arrangement of interconnected blocks to store data in a secure manner. Every block is distinct and has its own attributes that enable it to be filled, linked, and secured with the help of adjacent blocks. This structure is responsible for the name blockchain and distinguishes it from conventional databases, which usually store data in tables.

Valuable Characteristics of Blockchain

Digital Signatures and Hashing Functions

A hash function is a class of algorithms that creates a distinct, predetermined-length identifier for any given entity or text. This identifier is unique to that specific entity or text, and any alteration, no matter how minor, will generate a completely different identifier.

This article aims to investigate the SHA256 hash algorithm that is employed in the Bitcoin network. SHA256 is a hashing function that generates 64 hexadecimal characters as output, regardless of the dimensions of the input. Hence, SHA256 is a consistent and trustworthy means of data encryption.

The inclusion of a dot (.) can profoundly influence the hash function. To create the chain in a blockchain, the data from each block is omitted and directly fed into the hash function. Succeeding blocks are then connected to it through their corresponding hashes, and the process is repeated.

What are the Benefits of Using Crystal?

Crystal is an optimal selection for developers who desire more independence and better performance. Its advanced type inference mechanism can be utilized to address concerns about type declaration or method naming.

Crystal’s easy-to-use interface is well-suited for developers who have previous knowledge of the Ruby programming language. Unlike interpreted languages like JavaScript and Ruby, Crystal is a compiled language, making it more efficient and requiring less memory to function. Moreover, Crystal employs LLVM to construct native code, which further enhances its performance. The compiler is also statically typed, allowing it to detect type errors during the compilation process, which provides developers with an extra layer of protection.

Constructing a Blockchain using the Crystal Programming Language: A Comprehensive Guide

The following guide will demonstrate each step of constructing a blockchain with Crystal.


To begin building a blockchain with Crystal, the first step is to install the language. Crystal is currently compatible with Linux, FreeBSD, macOS and OpenBSD operating systems.Learn more about how to create a more diverse staff.

Following the installation of the compiler, a crystal binary will become accessible.

Execute the subsequent command to generate the application:

The following command creates a Crystal application named crystal-blockchain-technology:

Cryptography-Based Blockchain Technology using Crystal

While developing applications with Crystal, you have the freedom to select any web framework that suits your needs. To initiate HTTP requests to the blockchain, you must indicate the location in the blockchain.yml file. You can tailor this file to include the dependencies you have chosen.

Next, the file should be executed by utilizing the ‘shards install’ command. Shards are frequently utilized to segregate software and media libraries. To ensure efficient distribution of resources, each shard is located on its own instance of the database server.

This enables the creation of a data model that defines the visual characteristics of the blocks. To take advantage of Crystal::Blockchain::Technology, the pertinent information should be integrated into the appropriate module.

A global blockchain variable can be established to hold a set of local variables, with each key assigned a specific data type. We recommend experimenting with the different data types to familiarize yourself with various options, as this will aid in the conversion to JSON when retrieving the blockchain using a GET request.

To maintain the integrity of the blockchain, each block is equipped with a hash corresponding to the previous block. This ensures the reliability of the blockchain. Furthermore, a separate file called can be created in the src/ folder, that can be converted into a module or a class.

By utilizing the command “extend self,” you can add an additional module to an existing one. By extending a block with “extend Block,” you can increase its length.

It is now time to begin the initial methodology using Crystal. An essential aspect of building Blockchain Technology is clicking the “Create” button, which initiates the process of creating a new block. These parameters are fixed, hence it is important to use them to unite and produce a novel key-value pair.

The new key-value pair will be appended to the output of the previous example, resulting in a Blockchain Technology. This technology is revealed upon implementation of the associated function, self.calculate hash. This involves hashing the data from the existing block with the data from subsequent blocks, then concatenating the resulting string.

Secure Hash Algorithm (SHA) 256 is a unidirectional cryptographic hash function utilized for encrypting data. It generates a 256-bit fixed-length output for any input data, regardless of size. This guarantees that identical input data will generate identical output. SHA-256 is often used to produce a hexadecimal representation of the hash, allowing it to be integrated into many libraries. This permits the hashing of individual items or an entire library, producing a 256-bit string as an output.

It is crucial to recognize that any modifications made to a single character within a hash can have a far-reaching impact on the entire system. As previously mentioned, hashes are fundamental in connecting blocks and play a crucial role in ensuring the security and reliability of the blockchain. If any malicious modifications are made to the blockchain, the hashes will change, resulting in a break in the chain.

Building and Investigating the Blockchain

In this segment, we will delve into the potential of With this technology, it is possible to construct a unique block and add it to the distributed ledger. Furthermore, a distinct endpoint is designated in the module to provide access to the blockchain as JSON. You also have the option to restart your server, if necessary.

To achieve our objective, it is essential to utilize a web framework and block module.

require “Kemal”.

require “./Block”.

Type crystal src/ in the terminal to initiate the server. Launch a web browser and type

https://localhost:3000 to see the blockchain with its first block. Get a browser extension to view JSON if you don’t already have one.

Adding Additional Blocks to Complete the Blockchain

Mining is a crucial step in the process of appending a new block to a blockchain network. The Proof-of-Work (PoW) protocol is the commonly accepted method of authenticating the data of newly appended blocks. In PoW, miners compete to be the first to confirm the validity of the block. This incentivizes miners to participate in the process as they are compensated for their effort. The PoW protocol also ensures that miners are accountable for the accuracy of their validation, resultantly expediting the addition of new blocks, and establishing a system of counterbalances.

At any point in time, only a single chain of blocks can be deemed as the authoritative account of the blockchain’s narrative. If multiple chains have the same number of blocks, the chain with a greater number of blocks will be selected, and the rest will be discarded.

The operational ideology of Bitcoin includes the transformation of hash combinations produced by a participant into a string of numbers and letters. The block hash assures that the whole string equals zero. This procedure is coined as a ‘nonce,’ as the alphanumeric combination results in a preface of zero. By utilizing this principle, it is possible to instantly dial phone numbers starting with zero.

In level four of the challenge, the quantity of zeroes in the input is multiplied by four. Once the zeroes have all been identified, the subsequent digit is the nonce. The nonce number is subsequently hashed, along with the block that produced the fourth level challenge, employing the SHA-256 algorithm. Utilizing the SHA-256 method can authenticate this process.

Scripting the Bitcoin Blockchain

To improve the NamedTuple declarations, including a nonce and data difficulty as two more key-value pairs is a suitable initial step. A 32-bit integer can be employed as an index to indicate the degree of complexity, which is decidedly distinct.

A Crystal integer can possess either a plus sign (+) or a minus sign (-) prefix, accompanying a series of digits and an underscore, and can also have a suffix. If a suffix is omitted, the integer will represent the integer type between a signed 32-bit integer (Int32) and an unsigned 64-bit integer (UInt64) with lesser significance.

If a suffix is not mentioned, the default data type for both the index and the complexity level is Int32. When accepting zero-based integers, the count begins at 0. The complexity level can be anywhere between Uint8 and Uint64, depending on the user’s choice.

For storing a value, an unsigned 32-bit integer is frequently sufficient. When building a NamedTuple, you’re at liberty to choose any numeric value without first designating its data type.

To establish a connection between the two, it’s critical to ensure that the create function has pertinent information. The nonce parameter can be initialized using an empty string, and the complexity level can be adjusted according to the preferred level of complexity.

By selecting the most stringent block module configuration, the system will evaluate your process. After implementing a completely operational blockchain, the process of appending a block to the blockchain will be regulated.

To compute the hash in the last slot of the plain text interpolation, you can now use #block[:nonce]. This ensures that your block’s hash corresponds with its nonce. The next move is to access the create method within the script.

Utilize the create method if you’re constructing a block within the generate method. Once all of the blocks have been generated, launch a new loop that will iterate through them. In each cycle of the loop, the loop’s iteration index should be passed as an argument. As the loop advances, it will generate a hexadecimal string which can be merged with the block’s nonce key.

The ‘Is Hash Valid?’ function can be used, which considers the most recent Nonce and the Loop Indicator, to determine whether the Hash of the present Block continues to be valid throughout iterations of the Loop. This approach is useful in accurately understanding the technique employed in the Block Module. Additionally, the Hash must commence with the right number of zeroes to satisfy the level of complexity required.

By utilizing the create method within the for loop, it is possible to validate whether the problem has been resolved successfully. To observe any changes in the outcome, it is necessary to re-perform the actions with a different value for the variable. Users have the flexibility of adjusting the number of variables as they see fit, which enables them to monitor the output while maintaining consistent input settings for each iteration. This technique offers a way to detect similar outcomes and aids in evaluating the complexity of the problem.

To append a new block to an existing blockchain.

One can generate a new block on the Crystal Blockchain Technology platform by visiting the website and incorporating a route handler. Upon adding the handler, POST requests can be managed via the /new-block endpoint to obtain data saved in the data key. To create the new block, the information from the preceding block on the blockchain must be merged with the fresh data to generate a new block.

It’s crucial to verify that the most recently added block remains unaltered prior to appending it to the blockchain, as any changes could result in data loss and cause the blockchain to malfunction. To ensure this, an updated procedure needs to be integrated into

If the hash of a newly added block is equivalent to the hash of an already existing block, it’s important to verify that the block’s index has been incremented. Furthermore, if utilizing the calculate hash function on the current block results in the same outcome as when used on the previous block, then the criteria has been met. If all of these conditions are satisfied, then the newly appended block can be accepted.

Presently, it’s possible to append new blocks to the blockchain. You can test the functionality of your API requests using Postman.

Kindly forward a POST request to

https://localhost:3000/new-blocks with JSON body of {“data”: “Newly added data to your second block”}. If all runs smoothly, you will see the new block created and it will respond to the calls from Postman.

After you start incorporating log entries in your blocks, you can quickly access the terminal. The terminal output will provide information regarding any unsuccessful attempts to generate new blocks. Upon completion of the mining process, the terminal will display the successful nonce and the latest resultant blocks.

Temporarily halt the iterations for mining a new block. The blockchain can also be viewed from a web browser.

It’s worth noting that all hashes generated after the latest block will always start with the number ‘0’ appearing thrice. You can modify the challenge to monitor how the hash changes. A relationship exists between the hash of the preceding block and the previous hash of every block. It’s important to keep in mind that if the level of difficulty is elevated significantly, then it’ll take a considerable amount of time to find a solution.

This guide presents a detailed introduction to developing a blockchain using the Crystal programming language. It begins with the basics and progresses towards installing a blockchain, configuring an application that facilitates safe data sharing on the blockchain, and finally mining the completed project. To ensure the security of the blockchain, it’s crucial to record an adequate number of blocks and records prior to launch. The project should be launched concurrently on numerous machines to ensure optimal efficiency, which creates a network for mining the final product.

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