Module: SharedBroker::Cipher

Defined in:
lib/shared_broker/cipher.rb

Defined Under Namespace

Classes: DecryptionError

Constant Summary collapse

ALGORITHM = 
"aes-256-gcm"

Class Method Summary collapse

Class Method Details

.clean_envelope_metadata!(metadata) ⇒ Object 



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# File 'lib/shared_broker/cipher.rb', line 90

def self.clean_envelope_metadata!(metadata)
  metadata.delete(:_encrypted)
  metadata.delete(:_iv)
  metadata.delete(:_auth_tag)
  metadata.delete(:_data)
  metadata.delete(:_key_id)
end

.decrypt(payload_hash, key_provider_or_key, topic: nil) ⇒ Object 



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# File 'lib/shared_broker/cipher.rb', line 45

def self.decrypt(payload_hash, key_provider_or_key, topic: nil)
  return payload_hash unless payload_hash.is_a?(Hash) && payload_hash[:_encrypted]
  return payload_hash unless key_provider_or_key

  key = resolve_decryption_key(payload_hash, key_provider_or_key, topic)
  return payload_hash unless key

  cipher = OpenSSL::Cipher.new(ALGORITHM)
  cipher.decrypt
  cipher.key = key
  cipher.iv = Base64.strict_decode64(payload_hash[:_iv])
  cipher.auth_tag = Base64.strict_decode64(payload_hash[:_auth_tag])

  encrypted_bytes = Base64.strict_decode64(payload_hash[:_data])
  decrypted_json = cipher.update(encrypted_bytes) + cipher.final

  decrypted_data = JSON.parse(decrypted_json, symbolize_names: true)
  
  metadata = payload_hash.select { |k, _| k.to_s.start_with?("_") }
  clean_envelope_metadata!(metadata)

  decrypted_data.merge(metadata)
rescue => e
  raise DecryptionError, "Failed to decrypt payload. Error: #{e.message}. Offending payload: #{payload_hash.inspect}"
end

.encrypt(payload_hash, key_provider_or_key, topic: nil) ⇒ Object 



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# File 'lib/shared_broker/cipher.rb', line 13

def self.encrypt(payload_hash, key_provider_or_key, topic: nil)
  return payload_hash unless key_provider_or_key

  unless payload_hash.is_a?(Hash)
    raise ArgumentError, "Expected payload_hash to be a Hash, got #{payload_hash.class} with value #{payload_hash.inspect}"
  end

  key, key_id = resolve_encryption_key(key_provider_or_key, topic)
  return payload_hash unless key

  metadata = payload_hash.select { |k, _| k.to_s.start_with?("_") }
  data_to_encrypt = payload_hash.reject { |k, _| k.to_s.start_with?("_") }

  cipher = OpenSSL::Cipher.new(ALGORITHM)
  cipher.encrypt
  cipher.key = key
  iv = cipher.random_iv

  encrypted_data = cipher.update(data_to_encrypt.to_json) + cipher.final
  auth_tag = cipher.auth_tag

  envelope = {
    _encrypted: true,
    _iv: Base64.strict_encode64(iv),
    _auth_tag: Base64.strict_encode64(auth_tag),
    _data: Base64.strict_encode64(encrypted_data)
  }
  envelope[:_key_id] = key_id.to_s if key_id

  metadata.merge(envelope)
end

.resolve_decryption_key(payload, provider_or_key, topic) ⇒ Object 



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# File 'lib/shared_broker/cipher.rb', line 81

def self.resolve_decryption_key(payload, provider_or_key, topic)
  if provider_or_key.respond_to?(:key_for_id)
    key_id = payload[:_key_id]
    key_id ? provider_or_key.key_for_id(key_id) : provider_or_key.key_for(topic)
  else
    provider_or_key
  end
end

.resolve_encryption_key(provider_or_key, topic) ⇒ Object 



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# File 'lib/shared_broker/cipher.rb', line 73

def self.resolve_encryption_key(provider_or_key, topic)
  if provider_or_key.respond_to?(:key_for)
    [provider_or_key.key_for(topic), provider_or_key.active_key_id_for(topic)]
  else
    [provider_or_key, nil]
  end
end