https://github.com/alandefreitas/blockchain
Blockchain Container (C++) Proof of Concept
https://github.com/alandefreitas/blockchain
blockchain blockchain-technology cryptocurrencies cryptocurrency
Last synced: 7 months ago
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Blockchain Container (C++) Proof of Concept
- Host: GitHub
- URL: https://github.com/alandefreitas/blockchain
- Owner: alandefreitas
- Created: 2018-02-23T16:29:34.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2018-02-23T16:30:17.000Z (over 7 years ago)
- Last Synced: 2025-01-25T09:22:47.207Z (9 months ago)
- Topics: blockchain, blockchain-technology, cryptocurrencies, cryptocurrency
- Language: C++
- Homepage:
- Size: 3.91 KB
- Stars: 2
- Watchers: 3
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# Blockchain C++ Container
## Integration
Simply include the `blockchain.h` header.
```cpp
#include "blockchain.h"
```
The examples below are using the namespace `bc`:
```cpp
using namespace bc;
```
## Creating a blockchain
Creating a blockchain of strings with "Hello, World!" in its genesis block:
```cpp
blockchain bc("Hello, World!");
std::cout << bc.back().block_hash << ": " << bc.back().transaction << std::endl;
```
## Pushing new blocks/transactions
The usual `push_back` function can be used to insert new blocks:
```cpp
bc.push_back("A sent B a letter");
std::cout << bc.back().block_hash << ": " << bc.back().transaction << std::endl;
bc.push_back("B sent C a post card");
std::cout << bc.back().block_hash << ": " << bc.back().transaction << std::endl;
```
## Iterating the block chain
You can use:
* "for-each" loops
```cpp
for (block &b : bc) {
std::cout << b.block_hash << ": " << b.transaction << std::endl;
}
```
* iterators
```cpp
for (blockchain::iterator iter = bc.begin(); iter != bc.end(); ++iter) {
std::cout << iter->block_hash << ": " << iter->transaction << std::endl;
}
```
* indexed loops
```cpp
for (int i = 0; i < bc.size(); i++) {
std::cout << bc[i].block_hash << ": " << bc[i].transaction << std::endl;
}
```
## Checking hashes
The function `check_hash` iterates the blockchain to see if there's any inconsistency with the hashes.
```cpp
if (bc.check_hash()){
std::cout << "Blockchain hashes are consistent" << std::endl;
} else {
std::cout << "Blockchain hashes are not consistent" << std::endl;
}
```
The function `check_hash`, besides checking the hashes, recalculates the transaction hashes to make sure this hasn't been altered too.
```cpp
if (bc.check()){
std::cout << "Blockchain hashes and transactions are consistent" << std::endl;
} else {
std::cout << "Blockchain hashes and transactions are not consistent" << std::endl;
}
```
## "Hacking" the blockchain
Someone can try to hash the block chain with:
```cpp
// Trying to "hack" the blockchain
bc[0].transaction = "Hello moon";
```
The functions `check_hash` and `check` described above would then return false because the chain has been invalidated.