Bip39 Mnemonic generator, storage, and retrieval

[hadasz]

As a user I need a bip39 mnemonic generated for me that I can use to access my files.
The requirements are as follows:
-I am only given the 18 word mnemonic once. After that, I cannot retrieve it
-The key associated with the mnemonic is stored securely and locally on my iPhone
-The key associated with the mnemonic can be retrieved by SoJourn for decrypting my files
-The key can only be retrieved by Sojourn after I have authenticated with my fingerprint/passcode

[hadasz]

https://github.com/bitpay/bitcore-mnemonic/blob/master/lib/mnemonic.js
https://www.npmjs.com/package/react-native-aes-crypto