Class: PorkyLib::Symmetric

Inherits:
Object
  • Object
show all
Includes:
Singleton
Defined in:
lib/porky_lib/symmetric.rb

Constant Summary collapse

CMK_KEY_ORIGIN = 
'AWS_KMS'
CMK_KEY_USAGE = 
'ENCRYPT_DECRYPT'
SYMMETRIC_KEY_SPEC = 
'AES_256'

Instance Method Summary collapse

Instance Method Details

#client ⇒ Object 



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# File 'lib/porky_lib/symmetric.rb', line 15

def client
  require 'porky_lib/aws/kms/client' if PorkyLib::Config.config[:aws_client_mock]
  @client ||= Aws::KMS::Client.new
end

#cmk_alias_exists?(key_alias) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/porky_lib/symmetric.rb', line 33

def cmk_alias_exists?(key_alias)
  alias_list = client.list_aliases.to_h[:aliases]
  alias_list.each do |item|
    return true if item[:alias_name] == key_alias
  end

  false
end

#create_alias(key_id, key_alias) ⇒ Object 



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# File 'lib/porky_lib/symmetric.rb', line 46

def create_alias(key_id, key_alias)
  client.create_alias(target_key_id: key_id, alias_name: key_alias)
end

#create_key(tags, key_alias = nil, key_rotation_enabled = true) ⇒ Object 



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# File 'lib/porky_lib/symmetric.rb', line 20

def create_key(tags, key_alias = nil, key_rotation_enabled = true)
  resp = client.create_key(key_usage: CMK_KEY_USAGE, origin: CMK_KEY_ORIGIN, tags: tags)
  key_id = resp.to_h[:key_metadata][:key_id]

  # Enable automatic key rotation for the newly created CMK
  enable_key_rotation(key_id) if key_rotation_enabled

  # Create an alias for the newly created CMK
  create_alias(key_id, key_alias) if key_alias

  key_id
end

#decrypt(ciphertext_dek, ciphertext, nonce, encryption_context = nil) ⇒ Object 



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# File 'lib/porky_lib/symmetric.rb', line 90

def decrypt(ciphertext_dek, ciphertext, nonce, encryption_context = nil)
  return if ciphertext.nil? || ciphertext_dek.nil? || nonce.nil?

  # Decrypt the data encryption key
  plaintext_key = decrypt_data_encryption_key(ciphertext_dek, encryption_context)
  secret_box = RbNaCl::SecretBox.new(plaintext_key)

  should_reencrypt = false
  begin
    # Decrypt the message
    message = secret_box.decrypt(nonce, ciphertext)
  rescue RbNaCl::CryptoError
    # For backwards compatibility due to a code error in a previous release
    plaintext_key.replace(secure_delete_plaintext_key(plaintext_key.bytesize))
    message = secret_box.decrypt(nonce, ciphertext)
    should_reencrypt = true
  end

  # Securely delete the plaintext value from memory
  plaintext_key.replace(secure_delete_plaintext_key(plaintext_key.bytesize))

  [message, should_reencrypt]
end

#decrypt_data_encryption_key(ciphertext_key, encryption_context = nil) ⇒ Object 



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# File 'lib/porky_lib/symmetric.rb', line 58

def decrypt_data_encryption_key(ciphertext_key, encryption_context = nil)
  return client.decrypt(ciphertext_blob: ciphertext_key, encryption_context: encryption_context).plaintext if encryption_context

  resp = client.decrypt(ciphertext_blob: ciphertext_key)
  resp.plaintext
end

#decrypt_with_benchmark(ciphertext_dek, ciphertext, nonce, encryption_context = nil) ⇒ Object 



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# File 'lib/porky_lib/symmetric.rb', line 155

def decrypt_with_benchmark(ciphertext_dek, ciphertext, nonce, encryption_context = nil)
  return if ciphertext.nil? || ciphertext_dek.nil? || nonce.nil?

  encryption_statistics = {}

  plaintext_key = benchmark_block(encryption_statistics, :decrypt_key) do
    # Decrypt the data encryption key
    decrypt_data_encryption_key(ciphertext_dek, encryption_context)
  end

  message, should_reencrypt = benchmark_block(encryption_statistics, :decrypt) do
    secret_box = RbNaCl::SecretBox.new(plaintext_key)

    should_reencrypt = false
    begin
      # Decrypt the message
      message = secret_box.decrypt(nonce, ciphertext)
    rescue RbNaCl::CryptoError
      # For backwards compatibility due to a code error in a previous release
      plaintext_key.replace(secure_delete_plaintext_key(plaintext_key.bytesize))
      message = secret_box.decrypt(nonce, ciphertext)
      should_reencrypt = true
    end

    [message, should_reencrypt, encryption_statistics]
  end

  benchmark_block(encryption_statistics, :clear_key) do
    # Securely delete the plaintext value from memory
    plaintext_key.replace(secure_delete_plaintext_key(plaintext_key.bytesize))
  end

  [message, should_reencrypt, encryption_statistics]
end

#decrypt_with_key(ciphertext, plaintext_key, nonce) ⇒ Object 



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# File 'lib/porky_lib/symmetric.rb', line 214

def decrypt_with_key(ciphertext, plaintext_key, nonce)
  # Initialize the box
  secret_box = RbNaCl::SecretBox.new(plaintext_key)

  # Decrypt the message
  plaintext = secret_box.decrypt(nonce, ciphertext)

  result = OpenStruct.new

  result.plaintext = plaintext

  result
end

#decrypt_with_key_with_benchmark(ciphertext, plaintext_key, nonce) ⇒ Object 



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# File 'lib/porky_lib/symmetric.rb', line 255

def decrypt_with_key_with_benchmark(ciphertext, plaintext_key, nonce)
  encryption_statistics = {}

  plaintext = benchmark_block(encryption_statistics, :decrypt) do
    secret_box = RbNaCl::SecretBox.new(plaintext_key)

    # Decrypt the message
    plaintext = secret_box.decrypt(nonce, ciphertext)

    plaintext
  end

  result = OpenStruct.new

  result.plaintext = plaintext
  result.statistics = encryption_statistics

  result
end

#enable_key_rotation(key_id) ⇒ Object 



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# File 'lib/porky_lib/symmetric.rb', line 42

def enable_key_rotation(key_id)
  client.enable_key_rotation(key_id: key_id)
end

#encrypt(data, cmk_key_id, ciphertext_dek = nil, encryption_context = nil) ⇒ Object 



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# File 'lib/porky_lib/symmetric.rb', line 65

def encrypt(data, cmk_key_id, ciphertext_dek = nil, encryption_context = nil)
  return if data.nil? || cmk_key_id.nil?

  # Generate a new data encryption key or decrypt existing key, if provided
  plaintext_key = decrypt_data_encryption_key(ciphertext_dek, encryption_context) if ciphertext_dek
  ciphertext_key = ciphertext_dek if ciphertext_dek
  plaintext_key, ciphertext_key = generate_data_encryption_key(cmk_key_id, encryption_context) unless ciphertext_dek

  # Initialize the box
  secret_box = RbNaCl::SecretBox.new(plaintext_key)

  # First, make a nonce: A single-use value never repeated under the same key
  # The nonce isn't secret, and can be sent with the ciphertext.
  # The cipher instance has a nonce_bytes method for determining how many bytes should be in a nonce
  nonce = RbNaCl::Random.random_bytes(secret_box.nonce_bytes)

  # Encrypt a message with SecretBox
  ciphertext = secret_box.encrypt(nonce, data)

  # Securely delete the plaintext value from memory
  plaintext_key.replace(secure_delete_plaintext_key(plaintext_key.bytesize))

  [ciphertext_key, ciphertext, nonce]
end

#encrypt_with_benchmark(data, cmk_key_id, ciphertext_dek = nil, encryption_context = nil) ⇒ Object 



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# File 'lib/porky_lib/symmetric.rb', line 114

def encrypt_with_benchmark(data, cmk_key_id, ciphertext_dek = nil, encryption_context = nil)
  return if data.nil? || cmk_key_id.nil?

  encryption_statistics = {}

  # Generate a new data encryption key or decrypt existing key, if provided
  if ciphertext_dek
    plaintext_key = benchmark_block(encryption_statistics, :decrypt_key) do
      decrypt_data_encryption_key(ciphertext_dek, encryption_context)
    end

    ciphertext_key = ciphertext_dek
  else
    plaintext_key, ciphertext_key = benchmark_block(encryption_statistics, :generate_key) do
      generate_data_encryption_key(cmk_key_id, encryption_context)
    end
  end

  nonce, ciphertext = benchmark_block(encryption_statistics, :encrypt) do
    # Initialize the box
    secret_box = RbNaCl::SecretBox.new(plaintext_key)

    # First, make a nonce: A single-use value never repeated under the same key
    # The nonce isn't secret, and can be sent with the ciphertext.
    # The cipher instance has a nonce_bytes method for determining how many bytes should be in a nonce
    nonce = RbNaCl::Random.random_bytes(secret_box.nonce_bytes)

    # Encrypt a message with SecretBox
    ciphertext = secret_box.encrypt(nonce, data)

    [nonce, ciphertext]
  end

  benchmark_block(encryption_statistics, :clear_key) do
    # Securely delete the plaintext value from memory
    plaintext_key.replace(secure_delete_plaintext_key(plaintext_key.bytesize))
  end

  [ciphertext_key, ciphertext, nonce, encryption_statistics]
end

#encrypt_with_key(plaintext, plaintext_key) ⇒ Object 



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# File 'lib/porky_lib/symmetric.rb', line 194

def encrypt_with_key(plaintext, plaintext_key)
  # Initialize the box
  secret_box = RbNaCl::SecretBox.new(plaintext_key)

  # First, make a nonce: A single-use value never repeated under the same key
  # The nonce isn't secret, and can be sent with the ciphertext.
  # The cipher instance has a nonce_bytes method for determining how many bytes should be in a nonce
  nonce = RbNaCl::Random.random_bytes(secret_box.nonce_bytes)

  # Encrypt a message with SecretBox
  ciphertext = secret_box.encrypt(nonce, plaintext)

  result = OpenStruct.new

  result.ciphertext = ciphertext
  result.nonce = nonce

  result
end

#encrypt_with_key_with_benchmark(plaintext, plaintext_key) ⇒ Object 



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# File 'lib/porky_lib/symmetric.rb', line 228

def encrypt_with_key_with_benchmark(plaintext, plaintext_key)
  encryption_statistics = {}

  nonce, ciphertext = benchmark_block(encryption_statistics, :encrypt) do
    # Initialize the box
    secret_box = RbNaCl::SecretBox.new(plaintext_key)

    # First, make a nonce: A single-use value never repeated under the same key
    # The nonce isn't secret, and can be sent with the ciphertext.
    # The cipher instance has a nonce_bytes method for determining how many bytes should be in a nonce
    nonce = RbNaCl::Random.random_bytes(secret_box.nonce_bytes)

    # Encrypt a message with SecretBox
    ciphertext = secret_box.encrypt(nonce, plaintext)

    [nonce, ciphertext]
  end

  result = OpenStruct.new

  result.ciphertext = ciphertext
  result.nonce = nonce
  result.statistics = encryption_statistics

  result
end

#generate_data_encryption_key(cmk_key_id, encryption_context = nil) ⇒ Object 



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# File 'lib/porky_lib/symmetric.rb', line 50

def generate_data_encryption_key(cmk_key_id, encryption_context = nil)
  resp = {}
  resp = client.generate_data_key(key_id: cmk_key_id, key_spec: SYMMETRIC_KEY_SPEC, encryption_context: encryption_context) if encryption_context
  resp = client.generate_data_key(key_id: cmk_key_id, key_spec: SYMMETRIC_KEY_SPEC) unless encryption_context

  [resp.plaintext, resp.ciphertext_blob]
end

#secure_delete_plaintext_key(length) ⇒ Object 



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# File 'lib/porky_lib/symmetric.rb', line 190

def secure_delete_plaintext_key(length)
  "\0" * length
end