Trust Wallet backup file

[xbt]

Now Trust Wallet support cloud backup with file which very similar to Ethereum keystore file:

{
 "version" : 3,
 "crypto" : {
   "ciphertext" : "<ciphertext>",
   "cipherparams" : {
     "iv" : "<iv>"
   },
   "kdf" : "scrypt",
   "kdfparams" : {
     "r" : 8,
     "p" : 4,
     "n" : 16384,
     "dklen" : 32,
     "salt" : ""
   },
   "mac" : "<mac>",
   "cipher" : "aes-128-ctr"
 },
 "id" : "<wallet_id>",
 "activeAccounts" : [<list of addresses and public keys>],
 "name" : "<wallet name>",
 "type" : "mnemonic"
}

Salt here has empty value.
What mode can I use to crack it?