Switch fast-pbkdf2 for aes-crypto lib

Following the example from Metamask:
MetaMask/metamask-mobile#1769

package.json

@@ -36,7 +36,7 @@
     "react": "17.0.2",
     "react-dom": "17.0.2",
     "react-native": "0.68.2",
-    "react-native-fast-pbkdf2": "^0.3.1",
+    "react-native-aes-crypto": "^2.1.0",
     "react-native-gesture-handler": "~2.2.1",
     "react-native-get-random-values": "~1.8.0",
     "react-native-picker-select": "^8.0.4",

src/utils/crypto.ts

@@ -16,12 +16,14 @@ You should have received a copy of the GNU Lesser General Public License
 along with the library. If not, see <http://www.gnu.org/licenses/>.
 */
 
-import rnPbkdf2 from 'react-native-fast-pbkdf2'
+import { NativeModules } from 'react-native'
+
+const Aes = NativeModules.Aes
 
 export const pbkdf2 = async (password: string, salt: Buffer): Promise<Buffer> => {
   const _salt = salt.toString('base64')
-  const data = await rnPbkdf2.derive(password, _salt, 10000, 32, 'sha-256')
-  return Buffer.from(data, 'base64')
+  const data = await Aes.pbkdf2(password, _salt, 10000, 256)
+  return Buffer.from(data, 'hex')
 }
 
 // Directly from bip39 package
@@ -33,6 +35,6 @@ function salt(password: string) {
 export const mnemonicToSeed = async (mnemonic: string, passphrase?: string): Promise<Buffer> => {
   const mnemonicBuffer = new Buffer(mnemonic, 'utf-8')
   const salted = new Buffer(salt(passphrase ?? ''), 'utf-8')
-  const data = await rnPbkdf2.derive(mnemonicBuffer.toString('base64'), salted.toString('base64'), 2048, 64, 'sha-512')
-  return Buffer.from(data, 'base64')
+  const data = await Aes.pbkdf2(mnemonicBuffer.toString('base64'), salted.toString('base64'), 2048, 512)
+  return Buffer.from(data, 'hex')
 }