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 



105
106
107
108
109
110
111
112
 
# File 'lib/shared_broker/cipher.rb', line 105

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

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



53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
 
# File 'lib/shared_broker/cipher.rb', line 53

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_raw = cipher.update(encrypted_bytes) + cipher.final

  compression_alg = payload_hash[:_compression]
  decrypted_json = if compression_alg
                     SharedBroker::Compressor.decompress(decrypted_raw, compression_alg)
                   else
                     decrypted_raw
                   end

  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 



13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
 
# 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?("_") }
  json_data = data_to_encrypt.to_json

  compression_alg = nil
  if SharedBroker.compression_algorithm && json_data.bytesize > SharedBroker.compression_threshold
    compression_alg = SharedBroker.compression_algorithm
    json_data = SharedBroker::Compressor.compress(json_data, compression_alg)
  end

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

  encrypted_data = cipher.update(json_data) + 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
  envelope[:_compression] = compression_alg.to_s if compression_alg

  metadata.merge(envelope)
end

.resolve_decryption_key(payload, provider_or_key, topic) ⇒ Object 



96
97
98
99
100
101
102
103
 
# File 'lib/shared_broker/cipher.rb', line 96

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 



88
89
90
91
92
93
94
 
# File 'lib/shared_broker/cipher.rb', line 88

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