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def calculate_hash(block)
  plain_text = "
    #{block[:index]}
    #{block[:timestamp]}
    #{block[:data]}
    #{block[:prev_hash]}
    #{block[:nonce]}
  "
  sha256 = OpenSSL::Digest.new("SHA256")
  sha256.update(plain_text)

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def is_hash_valid?(hash, difficulty)
  prefix = "0" * difficulty
  hash.starts_with?(prefix)
end

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post "/new-block" do |env|
  data = env.params.json["data"].as(String)

  new_block = Block.generate(blockchain[blockchain.size - 1], data)

  if Block.is_valid?(new_block, blockchain[blockchain.size - 1])
    blockchain << new_block
    puts "\n"
    p new_block
    puts "\n"

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def is_valid?(new_block, old_block)
  if old_block[:index] + 1 != new_block[:index]
    return false
  elsif old_block[:hash] != new_block[:prev_hash]
    return false
  elsif self.calculate_hash(new_block) != new_block[:hash]
    return false
  end

  true

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# provider.tf

# Specify the provider and access details
provider "aws" {
  shared_credentials_file = "$HOME/.aws/credentials"
  profile                 = "default"
  region                  = var.aws_region
}

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# variables.tf

variable "aws_region" {
  description = "The AWS region things are created in"
  default     = "us-west-2"
}

variable "ecs_task_execution_role_name" {
  description = "ECS task execution role name"
  default = "myEcsTaskExecutionRole"

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# network.tf

# Fetch AZs in the current region
data "aws_availability_zones" "available" {
}

resource "aws_vpc" "main" {
  cidr_block = "172.17.0.0/16"
}

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# security.tf

# ALB Security Group: Edit to restrict access to the application
resource "aws_security_group" "lb" {
  name        = "cb-load-balancer-security-group"
  description = "controls access to the ALB"
  vpc_id      = aws_vpc.main.id

  ingress {
    protocol    = "tcp"

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# alb.tf

resource "aws_alb" "main" {
  name            = "cb-load-balancer"
  subnets         = aws_subnet.public.*.id
  security_groups = [aws_security_group.lb.id]
}

resource "aws_alb_target_group" "app" {
  name        = "cb-target-group"

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# ecs.tf

resource "aws_ecs_cluster" "main" {
  name = "cb-cluster"
}

data "template_file" "cb_app" {
  template = file("./templates/ecs/cb_app.json.tpl")

  vars = {