Firstly, follow the guide here: https://www.bitcoin.com/guides/how-to-import-and-export-bitcoin-private-keys
Create the password and then "copy to clipboard"...
Once you have the encrypted text, you can visit: https://bitwiseshiftleft.github.io/sjcl/demo/
- Paste the encrypted text into the purple "CipherText" box
- Enter your password in the green "Password" section
- Click the purple "decrypt" arrow
It will put the unencrypted wallet info into the red "plaintext" box.
The dummy wallet I decrypted gave me:
It seems to have the xPrivKey and the mnemonic... Both of which can be used on https://iancoleman.io/bip39/ with a derivation path of m/44'/0'/0'/0 (ie. click on the BIP44 tab) to generate a list of your addresses/private keys for importing to another wallet.
Or, you can simply restore the seed mnemonic into any BIP44 compatible wallet
With regards to "safety"... I usually recommend to run these sites OFFLINE by downloading them and running them locally... but you'd probably need to do that on a PC as opposed to your phone.
The bitwiseshiftleft page for decrypting the wallet can be downloaded here: https://github.com/bitwiseshiftleft/sjcl
(click the green "clone or download" button and select "download zip"... extract the zip and then open the index.html in the "demo" folder)... you might also be able to simply right click on the page and select "save as"
Ian Coleman can be downloaded following the instructions at the bottom of the page