Skip to content

Latest commit

 

History

History
236 lines (159 loc) · 7.94 KB

h.通用协议设计v1.3.md

File metadata and controls

236 lines (159 loc) · 7.94 KB

Protocol design

[TOC]

Common standards

Hashes

Usually, when a hash is computed within Satellite-chain, it is computed twice. Most of the time SHA-256 hashes are used, however RIPEMD-160 is also used when a shorter hash is desirable (for example when creating a NULS address).

Example of double-SHA-256 encoding of string "nuls":

nuls
96cc377699e3289875d6d40da436110d692e823eb8900ae13a7107cb36c7310c (first round of sha-256)
7e0590c37ab91aacabdac1bedec9ff6acd609215d019e489cc0a5dcf38b7b055(second round of sha-256)

For NULS addresses (RIPEMD-160) this would give:

nuls
96cc377699e3289875d6d40da436110d692e823eb8900ae13a7107cb36c7310c (first round is sha-256)
f8e8d1c6f1511c356effad8b986b0aa439a88c44(with ripemd-160)

Merkle Trees

Merkle trees are binary trees of hashes. Merkle trees in NULS use a double SHA-256, the SHA-256 hash of the SHA-256 hash of something.

If, when forming a row in the tree (other than the root of the tree), it would have an odd number of elements, the final double-hash is duplicated to ensure that the row has an even number of hashes.

First form the bottom row of the tree with the ordered double-SHA-256 hashes of the byte streams of the transactions in the block.

Then the row above it consists of half that number of hashes. Each entry is the double-SHA-256 of the 64-byte concatenation of the corresponding two hashes below it in the tree.

This procedure repeats recursively until we reach a row consisting of just a single double-hash. This is the Merkle root of the tree.

For example, imagine a block with three transactions a, b and c. The Merkle tree is:

d1 = dhash(a)
d2 = dhash(b)
d3 = dhash(c)
d4 = dhash(c)            # a, b, c are 3. that's an odd number, so we take the c twice

d5 = dhash(d1 concat d2)
d6 = dhash(d3 concat d4)

d7 = dhash(d5 concat d6)

where

dhash(a) = sha256(sha256(a))

d7 is the Merkle root of the 3 transactions in this block.

Addresses

A NULS address is in fact the hash of a ECDSA public key, computed this way:

ChainId = 2 byte,The ID of the chain in which the account belongs.
addressType = 1 byte,The type of the account,Example: 1 general account, 2 contract account……
pkh = 20 byte , RIPEMD-160(SHA-256(public key))
xor = 1 byte, XOR(chainId+addressType+pkh)
address = Base58Encode(chainId+addressType+pkh+xor)

非nuls体系的地址格式如下：

例如：比特币地址，在地址之前追加两个字节的chainId，之后跟随比特币的原始地址，地址解析方式根据链配置决定

address = Base58Encode(chainId+原始地址长度+原始地址+xor)

Message Structre

Satellite-chain uses custom messaging for communication over the TCP protocol.

  • Digital binary stream using little endian。
  • Floating point numbers convert to integers and transfer by little endian

Message

The message consists of a 24-byte header and payload.

*---------------------------------------------------------------*
|       Header(24 Byte)         |            Payload            |
*---------------------------------------------------------------*

message header

The main role of the header is to indicate the payload length, verify data integrity, and solve TCP sticky packets.

Len Fields Data Type Remark
4 MagicNumber uint32 Packet valid flag
12 command char[12] ASCII string identifying the packet content, NULL padded
4 PayloadLength uint32 Length of payload in number of bytes
4 checksum uint32 First 4 bytes of sha256(sha256(payload))

Common Structre

VarInt

Variable-length integers that can be encoded based on the values expressed to save space.

Value Len Structure
< 0xfd 1 uint8
<= 0xffff 3 0xfd + uint16
<= 0xffffffff 5 0xfe + uint32
> 0xffffffff 9 0xff + uint64

VarString

A variable-length byte stream consisting of a variable-length buffer. The string is encoded in UTF8.

Len Fields Data Type Remark
? length VarInt Length of the string
length value uint8[length] The string itself

VarByte

Variable-length buffer, consistent with the VarString implementation.

Len Fields Data Type Remark
? length VarInt Length of payload in number of bytes
length data byte[length] payload

Int48

6-byte number.

Network address

When a network address is needed somewhere, this structure is used.

Len Fields Data type Remark
16 IPv6/4 char[16] IPv6/4 address. Network byte order. The IPv4 address is written into the message as a 16 byte
2 port1 uint16 port number, network byte order
2 port2 uint16 port number,for cross-chain module

Block_headers

Len Fields Data Type Remark
4 version uint32 version bumber
32 preHash byte[32]
32 merkleRoot byte[32]
？ stateRoot VarByte
4 time uint32 second
2 txCount uint16
？ extends VarByte 本字段内容不同的链可设置不同的约束
? signature Varbyte

Transactions

Len Fields Data Type Remark
2 type uint16 交易类型
4 time uint32 时间，精确到秒
？ txData VarByte 业务数据
？ coinData VarByte 资产数据
？ remark VarString 备注
？ sig VarByte 只包含签名，不包含pubkey

交易特性

多账户转出
多账户转入
多资产转账

coinData结构

froms://List<CoinForm>格式，
tos://List<CoinTo>格式

CoinForm结构[40]

address:  //byte[24] 账户地址
assetsChainId://uint16 资产发行链的id
assetsId: //uint16 资产id
amount：  //uint128，转出数量
nonce  ： //byte[8] 交易顺序号，前一笔交易的hash的后8个字节
locked ： //byte 是否是锁定状态(locktime:-1),1代表锁定，0代表非锁定

CoinTo结构[44]

address:  //byte[24],目标地址
assetsChainId://uint16 资产发行链的id
assetsId: //uint16 资产id
amount :  //uint128，转账金额
lockTime：//uint32,解锁高度或解锁时间，-1为永久锁定

手续费

forms-tos剩余的部分就是手续费（模型中支持多种资产缴纳手续费，约束条件由经济模型设计决定）

Message Types

参考各个模块