Introduction

Vision uses an account model. The address is the unique identifier of an account, and a private key signature is required to operate an account. An account has many attributes, including VS& token balances, photon, entropy, Etc. VS's and tokens' transferring cost photon, smart contract related operations cost entropy. An account can apply to become a first validator candidate and accept votes from other accounts.
The account is the basis of all the VISION's activities.

Account creation

(1). Generate the address and private key using a wallet or explorer. Use these 2 ways to activate the account: Transfer VS/VRC-10 token to this address, the other way is transferring VS/VRC-10 in a contract. This operation costs extra 25,000 entropy.

(2). Call the CreateAccount contract from an existing account.

Account creation costs only photon. It burns VS if photonis insufficient.

Transferring VRC20 will not activate an account. However, the balance can be inquired from Visionscan by the address.

Key-pair Generation

Vision's signature algorithm is ECDSA, and the curve used is SECP256K1. A private key is a random number, and the corresponding public key is a point on the elliptic curve.
Generating process:

(1). Make a random number d as the private key.

(2). Calculate P = d * G as the public key. (G is the elliptic curve base point)

Address Format

Use the public key P as the input, and use SHA3 get the result H. The length of the public key is 64 bytes (SHA3 uses Keccak256). Use the last 20 bytes of H, and add a byte of 0x41 as a prefix. Do a basecheck (see next paragraph), and the result will be the final address. All addresses start with 'T'.

Basecheck process: first run SHA256 on the address to get h1, then run SHA256 on h1 to get h2. Use the first 4 bytes as a checksum, add it to the end of the address (address||check). Finally, base58 encode address||check to get the final result.

Character map
ALPHABET = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"

📘

address format equivalent

Because it uses the same key pair algorithm as Ethereum, Vision has made some changes on the address side for the convenience of memory and storage. E.g
An address on the Vision side
Address starting with V: VRbNprwjvBomKhvnhZq7Y33JRcrQJethpc
Beginning with 46: 46A3CFA732C835233DB3D6BF5F4A3C2D45B02EB6B9

Its equivalent Ethereum format address is
Start with 0x: 0xA3CFA732C835233DB3D6BF5F4A3C2D45B02EB6B9

All three addresses correspond to one account. When calling the native interface of Vision, use the address starting with V or 46, and select the format through the visible parameter. Use the address starting with 0x when calling Vision's JRPC interface.

Signature

Steps
(1). Transfer the rawdata of the transaction to byte[].
(2). Run SHA256 on the rawdata.
(3). Use the private key to sign the result of step 2.
(4). Add the signature to the transaction.

Algorithm

ECDSA, SECP256K
Example

priKey:::8e812436a0e3323166e1f0e8ba79e19e217b2c4a53c970d4cca0cfb1078979df
       
pubKey::04a5bb3b28466f578e6e93fbfd5f75cee1ae86033aa4bbea690e3312c087181eb366f9a1d1d6a437a9bf9fc65ec853b9fd60fa322be3997c47144eb20da658b3d1
        
hash:::159817a085f113d099d3d93c051410e9bfe043cc5c20e43aa9a083bf73660145
        
r:::38b7dac5ee932ac1bf2bc62c05b792cd93c3b4af61dc02dbb4b93dacb758123f
        
s:::08bf123eabe77480787d664ca280dc1f20d9205725320658c39c6c143fd5642d
        
v:::0

Note: The size of the signature result is 65 bytes:
r = 32 bytes
s = 32 bytes
v = 1 byte

Full node verifies the signature once receiving a transaction; it generates an address with the value of hash, r, s, and v, then it compares with the address in the transaction.

Demo

public static Transaction sign(Transaction transaction, ECKey myKey) {
    Transaction.Builder transactionBuilderSigned = transaction.toBuilder();
    byte[] hash = sha256(transaction.getRawData().toByteArray());
    List<Contract> listContract = transaction.getRawData().getContractList();

    for (int i = 0; i < listContract.size(); i++) {
      ECDSASignature signature = myKey.sign(hash);
      ByteString bsSign = ByteString.copyFrom(signature.toByteArray());

      //Each contract may be signed with a different private key in the future.
      transactionBuilderSigned.addSignature(bsSign);
    }
  }

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