question: public static MasterPrivateKey createFromEncryptedSeed ( String passphrase , byte [ ] encryptedSeed ) throws HyperLedgerException { try { byte [ ] key = SCrypt . generate ( passphrase . getBytes ( "UTF-8" ) , BITCOIN_SEED , 16384 , 8 , 8 , 32 ) ; SecretKeySpec keyspec = new SecretKeySpec ( key , "AES" ) ; if ( encryptedSeed . length != 32 ) { throw new HyperLedgerException ( "Incorrect encrypted seed length" ) ; } Cipher cipher = Cipher . getInstance ( "AES/ECB/NoPadding" , "BC" ) ; cipher . init ( Cipher . DECRYPT_MODE , keyspec ) ; return create ( cipher . doFinal ( encryptedSeed ) ) ; } catch ( UnsupportedEncodingException | NoSuchPaddingException | NoSuchProviderException | NoSuchAlgorithmException | InvalidKeyException | BadPaddingException | IllegalBlockSizeException e ) { throw new HyperLedgerException ( e ) ; } }
target:  Create a MasterPrivateKey from a seed, that is assumed to be encrypted. In practice often simply random.