## Blockchain
- 블ë¡ì²´ì¸ì€ 암호학과 수학 ë•ë¶„ì— ê°€ëŠ¥í•œ, **ì˜êµ¬ì ì •ë³´ì˜ ë³´ê´€ ê¸°ìˆ **ì„ ëœ»í•¨.
- 새로운 í”Œëž«í¼ (개발ìžê°€ ì‚¬ìš©í• ìˆ˜ìžˆëŠ” 플랫í¼)
- chain of block 블ë¡ë“¤ì´ 모여있는 ì²´ì¸.
- BlockChain ì„ **추가만 가능한 ë°ì´í„°ë² ì´ìŠ¤ë¼ê³ ìƒê°. ( 편집 , ì‚ì œ 불가 )**
- 탈중앙화 : íŠ¹ì • ê°œì¸ì´ DB를 ê´€ë¦¬í• ìˆ˜ 없다는 ì˜ë¯¸ (모ë‘ê°€ DBì˜ ë³µìž¬ë³¸ì„ ê°€ì§€ê³ ìžˆìŒ)
🎉 즉 **ë¶„ì‚°ëœ DB**ë¼ê³ í• ìˆ˜ 있다. ( => ê°ì‹œí•˜ê±°ë‚˜ í†µì œê°€ ì ˆëŒ€ì 으로 힘듬 )
## 블ë¡ì´ ì •ë³´ë¥¼ DBì— ì¶”ê°€í•˜ëŠ” 방법.
- 블ë¡í˜•íƒœë¡œ ì •ë³´ê°€ 추가ë¨.
- ë°ì´í„° + í•´ì‹œ(수학함수, ì¼ë°©í–¥ 함수, ê²°ì •ë¡ ì )
‼해시 : 수학함수, ì¼ë°©í–¥ 함수(ouputì„ ê°€ì§€ê³ inputì„ ì–»ì„ ìˆ˜ ì—†ìŒ) , ê²°ì •ë¡ ì ( input ì—대한 outputì´ ì •í•´ì ¸ìžˆìŒ. )
=> ê²°êµ í•„ìš”í•œ 것: ( ë°ì´í„° + ì´ì „ 블ë¡ì˜ í•´ì‹œ ) í•´ì‹œ
typescriptë¡œ ë§Œë“ blockchain
ê²€ì¦ê³¼ì •ì„ ìµœì†Œí™”ì‹œí‚¨ë²„ì ¼
```typescript
import * as CryptoJS from "crypto-js";
class Block {
static calculateBlockHash = (
index: number,
previousHash: string,
timestamp: number,
data: string
): string =>
CryptoJS.SHA256(index + previousHash + timestamp + data).toString();
static validateStructure = (aBlock: Block): boolean =>
typeof aBlock.index === "number" &&
typeof aBlock.hash === "string" &&
typeof aBlock.previousHash === "string" &&
typeof aBlock.timestamp === "number" &&
typeof aBlock.data === "string";
public index: number;
public hash: string;
public previousHash: string;
public data: string;
public timestamp: number;
constructor(
index: number,
hash: string,
previousHash: string,
data: string,
timestamp: number
) {
this.index = index;
this.hash = hash;
this.previousHash = previousHash;
this.data = data;
this.timestamp = timestamp;
}
}
const genesisBlock: Block = new Block(
0,
"202031210312313",
"",
"hello",
123456
);
let blockChain: [Block] = [genesisBlock]; //Block ê°ì²´ë§Œ ë°›ì„수있는 ë°°ì—´
const getBlockchain = (): Block[] => blockChain;
const getLatestBlock = (): Block => getBlockchain()[blockChain.length - 1];
const getNewTimeStamp = (): number => Math.round(new Date().getTime() / 1000);
const createNewBlock = (data: string): Block => {
const previousBlock: Block = getLatestBlock();
const newIndex: number = previousBlock.index + 1;
const newTimestamp: number = getNewTimeStamp();
const newHash: string = Block.calculateBlockHash(
newIndex,
previousBlock.hash,
newTimestamp,
data
);
const newBlock: Block = new Block(
newIndex,
newHash,
previousBlock.hash,
data,
newTimestamp
);
addBlock(newBlock);
return newBlock;
};
const getHashforBlock = (aBlock: Block): string =>
Block.calculateBlockHash(
aBlock.index,
aBlock.previousHash,
aBlock.timestamp,
aBlock.data
);
const isBlockValid = (candidateBlock: Block, previousBlock: Block): boolean => {
if (!Block.validateStructure(candidateBlock)) {
return false;
} else if (previousBlock.index + 1 !== candidateBlock.index) {
return false;
} else if (previousBlock.hash !== candidateBlock.previousHash) {
return false;
} else if (getHashforBlock(candidateBlock) !== candidateBlock.hash) {
return false;
} else {
return true;
}
};
const addBlock = (candidateBlock: Block): void => {
if (isBlockValid(candidateBlock, getLatestBlock())) {
blockChain.push(candidateBlock);
}
};
createNewBlock("second block");
createNewBlock("third block");
createNewBlock("fourth block");
console.log(blockChain);
export {};
```