Class: Laksa::Crypto::KeyStore

Inherits:
Object
  • Object
show all
Defined in:
lib/laksa/crypto/key_store.rb

Constant Summary collapse

T_PBKDF2 = 
'pbkdf2'
T_SCRYPT = 
'scrypt'

Instance Method Summary collapse

Constructor Details

#initialize ⇒ KeyStore

Returns a new instance of KeyStore.



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# File 'lib/laksa/crypto/key_store.rb', line 13

def initialize
end

Instance Method Details

#decrypt_private_key(encrypt_json, password) ⇒ Object

decrypt_private_key

Recovers the private key from a keystore file using the given passphrase.

Parameters:

  • encrypt_json (KeystoreV3)
  • password (string) 


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# File 'lib/laksa/crypto/key_store.rb', line 75

def decrypt_private_key(encrypt_json, password)
  datas = JSON.parse(encrypt_json)

  ciphertext = Util.decode_hex(datas['crypto']['ciphertext'])
  iv = Util.decode_hex(datas['crypto']['cipherparams']['iv'])
  kdfparams = datas['crypto']['kdfparams']
  kdf_type = datas['crypto']['kdf']

  case kdf_type
  when T_PBKDF2
    derived_key = PBKDF2.new(password: password, salt: kdfparams['salt'].pack('c*'), key_length: kdfparams['dklen'], iterations: kdfparams['c']).value
  when T_SCRYPT
    derived_key = SCrypt::Engine.scrypt(password, kdfparams['salt'].pack('c*'), kdfparams['n'], kdfparams['r'], kdfparams['p'], kdfparams['dklen'])
  end

  encrypt_key = derived_key[0..15]

  mac = generate_mac(derived_key, ciphertext)
  
  raise 'Failed to decrypt.' if mac.casecmp(datas['crypto']['mac']) != 0

  cipher = OpenSSL::Cipher.new(datas['crypto']['cipher'])
  cipher.decrypt 
  cipher.iv = iv
  cipher.key = encrypt_key
  cipher.padding = 0
  
  private_key = cipher.update(ciphertext) + cipher.final

  return Util.encode_hex private_key
end

#encrypt_private_key(private_key, password, kdf_type) ⇒ Object

encryptPrivateKey

Encodes and encrypts an account in the format specified by github.com/ethereum/wiki/wiki/Web3-Secret-Storage-Definition. However, note that, in keeping with the hash function used by Zilliqa’s core protocol, the MAC is generated using sha256 instead of keccak.

NOTE: only scrypt and pbkdf2 are supported.

Parameters:

  • private_key (string) —

    • hex-encoded private key

  • password (string) —

    • a password used for encryption

  • kdf_type (KDF) —

    • the key derivation function to be used



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# File 'lib/laksa/crypto/key_store.rb', line 28

def encrypt_private_key(private_key, password, kdf_type)
  address = KeyTool.get_address_from_private_key(private_key)

  iv = KeyTool.generate_random_bytes(16)
  salt = KeyTool.generate_random_bytes(32)

  case kdf_type
  when T_PBKDF2
    derived_key = PBKDF2.new(password: password, salt: salt, key_length: 32, iterations: 262144).value
  when T_SCRYPT
    derived_key = SCrypt::Engine.scrypt(password, salt, 8192, 8, 1, 32)
  end

  encrypt_key = derived_key[0..15]

  cipher = OpenSSL::Cipher.new('aes-128-ctr')
  cipher.encrypt
  cipher.iv = iv
  cipher.key = encrypt_key
  cipher.padding = 0
  
  ciphertext = cipher.update(Util.decode_hex(private_key)) + cipher.final

  mac = generate_mac(derived_key, ciphertext)

  datas = {address: address, 
    crypto: {
      cipher: 'aes-128-ctr', 
      cipherparams: {'iv': Util.encode_hex(iv)}, 
      ciphertext: Util.encode_hex(ciphertext), 
      kdf: kdf_type, 
      kdfparams: {n: 8192, c:262144, r:8, p:1, dklen: 32, salt: salt.bytes}, 
      mac: mac
    },
    id: SecureRandom.uuid, 
    version: 3
  }

  datas.to_json
end