This APP is used to store your account and password to ethereum blockchain, but before upload to the blockchain, we use your private key to encrypt it where is create at launch time.
Firstly, launch the app and create a blockchain account with your password, this process will create a blockchain public and private key locally, no one know this accounts private key, and it will be encrypted by the password input and save the ciphertext locally. No server will save you password and ciphertext, so its definitely safe.
Secondly, because of no server to save your private information, so please export your ciphered text as a QR code image to somewhere to backup your account. if you lose it or delete the app without the backup of this account, no one can find your account and password. It totally decentralized application, fully block chain, completely safe, even you yourself cant steal this when you lost this ciphered text or forget the password to decrypt this ciphered text, so be careful about this QR code image. Also, dont be worried too much about this QR code image, even someone steal this image, he cant decrypt your account expect he also gets your password which is no place to be stored. The password only is stored in your brain, so dont forget the password of this application. Do you know the story about someone who lost his bitcoin account?
Thirdly, please apply the free BPTs and Diamonds of the trial version, the blockchain will send some BPTs and Diamonds to use. The BPTs are used by the membership of this App. Before you create an Account-Password pair on the blockchain, you must recharge your membership firstly. It costs 2 BPTs per month, It authorizes you to operate on a blockchain. But the operation on the blockchain is not free, then it requires diamonds to reward the miner of the blockchain. So the Diamonds are used to reward them, and their duty is to make sure the blockchain be safe and never lost data. It costs about 4 Diamonds per operation, but it is not a constant value, it depends on the difficulty of the mining process and the price of gas used to operate blockchain.
Fourthly, after save you saving Account-Password encrypted data to the blockchain , you can synchronize these data anytime and anywhere, even you can see them on some blockchain explorer such as:etherscan.io but these data is encrypted by your private key. So before you look at the Account-Password value, you should decrypt your blockchain account and then the app can use your private key to decrypt the data. For the sake of safety, the private key must be removed from memory sometimes later, the default duration of the private key opened is 5 minutes, you can change it in the setting tab page.