Simple demonstration about md5 login

console.rb

>> authenticate?(3, 'one')
=> false
>> authenticate?(1, 'one1')
=> false
>> authenticate?(1, 'one')
=> true

md5_login.rb

class Account < Struct.new(:id, :digest_password)
  # Check if password is valid
  #
  # @param password [String] The user password
  # @return [Boolean] True when given password match with encrypted user password
  def valid_password?(password)
    self.class.encrypt(password) == digest_password
  end

  # Create a new Account
  #
  # @param options [Hash] List of attributes to the account
  # @option options [Integer] :id The account ID
  # @option options [Integer] :id The account plain password (Application are going to encrypt and safe store password)
  # @return [Account] Return an instance of Account
  def self.create(id:, password:)
    new(id, encrypt(password))
  end

  # Encrypt string using MD5
  # 
  # @param value [String] The string that should be encrypted
  # @return [String] hexdigest generated with MD5 algorithm
  def self.encrypt(value)
    Digest::MD5.hexdigest(value.to_s)
  end
end

# Add accounts to the @accounts instance variable
@accounts = []
@accounts << Account.create(id: 1, password: 'one') #<struct Account id=1, digest_password="f97c5d29941bfb1b2fdab0874906ab82">
@accounts << Account.create(id: 2, password: 'two') #<struct Account id=2, digest_password="b8a9f715dbb64fd5c56e7783c6820a61">

# Define authenticate method
# @param id [Number] the account id
# @param password [String] the account password
# @return [Boolean] Return true if account exist and given password match, or false in case of missing id or invalid password
def authenticate?(id, password)
  account = @accounts.find { |a| a.id == id }
  return false unless account

  account.valid_password?(password)
end