Frequently Asked Questions about BlockRecord

General questions about the app
A: The currently released BlockRecord is a beta version of the test release. In the official version, we plan to connect to Ethereum's main net, but in the beta version we connect to the test net (Ropsten). Since test nets are blockchains for testing, they are not guaranteed to be durable. Please note that the written hash may disappear.
A: Currently, only English version is available.
A: If you can not receive SMS, you can not register as a user.
A: Not required. However, when using the certificate screen, authentication by email address may be required.
A: You can use the app even if you do not have a cryptocurrency.
A: You can use this app without registering your real name.However, for users who wish to have a verified account, they must register with their real name.
A: There is no PC version. We offer only smartphone (iOS · Android) application.

Questions about how to use BlockRecord and its functions
A: BlockRecord does not have a delete post function. The blockchain used by BlockRecord is characterized by the fact that once data is recorded it is difficult to delete. This feature prevents the falsification of the recorded data.
A: Confirm button is a button to indicate that the user "Confirmed the fact of the posting (Confirm)". The post for which the Confirm button was pressed displays the name and date of the user who confirmed the button.
A: There is no function to cancel "Confirm".
A: Yes. Open the Account Settings screen, tap "Edit profile" in the upper right, and tap "Name: xxx" to change the name.However, the name of the verified account can not be changed.
A: There is a possibility that the balance of cryptocurrency (ETH) for Ropsten testnet required for using Public mode is insufficient. The following is an example of the ETH replenishment procedure.

1. Open the setting screen of BlockRecord, and tap the character string displayed in the "Address" section of "Blockchain Settings".
2. The "Recieve ETH" screen is displayed. Tap "Copy Address" at the bottom of the screen to copy your own address.
3. Paste the copied address on and press "Send me test Ether" to add BlockRecord with ETH for Ropsten testnet.
A: It's like a user's account number, which you need to send and receive cryptocurrency.
A: There is no chat function, but you can exchange messages by sharing text posts with friends.
A:Currently, all PDF files are renamed to "Contract.pdf".
A:You can post videos and audio data by selecting a file from "Album".

Question about certification function
A: The ID assigned to the user's post.
A: Indicates where the data posted by the user is stored.
The post data of the user is calculated by the hash function. The hash function is explained in detail in the answer of "Q: Why can I prove that posts recorded on BlockRecord have not been tampered with?" Below.
A: BlockRecord uses a one-way hash function encryption technology and block chain technology to prove that the written content has not been tampered with. One-way hash function is a function used for applications such as information security, and has the property that it can encrypt the original data and can not infer the original data from the encrypted data. Also, the hash function has the feature that exactly the same hash value is always generated from the same original data.

Blockchain is a distributed ledger technology, which is a database that stores data by generating data units called blocks at regular intervals and connecting them on chains. Data written to a blockchain can not be changed without the approval of more than half of all nodes participating in the blockchain. BlockRecord uses Ethereum, an open blockchain with thousands of nodes participating.

BlockRecord assigns FactID to posted data (called original data) and performs encryption using a one-way hash function. By writing the encrypted data (hash value) thus obtained to Ethereum, it is possible to hold "when", "who (whose account)" and "which data" are written in a non-alterable manner. Due to the nature of the one-way hash function, the hash values enerated from the same source data will be the same. If you want to make sure that a piece of data has not been tampered with, output the hash value of the current data you want to check, and compare it with the past hash value of that data recorded in the block chain. If they match, the data has not been tampered with.
A. Yes. The public blockchain in which the hash value is written is not managed by Centaur work Inc., but distributed, stored and published to nodes all over the world. If you use a commonly used free viewer such as Etherscan, you can check the information about "when", "who" (which account), and "what data". In addition, recalculation of the hash value from the current data can be performed by anyone using a general hashing tool.

Records written to a blockchain using BlockRecord can exist and be referenced as long as Ethereum blockchains survive, even if Centaur Works Inc. stops or disappears. BlockRecord is an autonomous and distributed data storage mechanism.
A. You may not have access. With BlockRecord, the author of a post specifies which users can access it.