Merge pull request #192 from Hemanth11011/feature/myfeature

Add basic blockchain and update README

Author: Techiral

B/basic-blockchain/basic-blockchain.py

@@ -0,0 +1,99 @@
+import datetime
+import hashlib
+import json
+from flask import Flask,jsonify
+
+# Building the Blockchain
+
+class Blockchain:
+    
+    def __init__(self):
+        self.chain = []
+        self.create_block(proof = 1, previous_hash='0')
+    
+    def create_block(self,proof,previous_hash):
+        block = {'index': len(self.chain)+1,
+                 'timestamp': str(datetime.datetime.now()),
+                 'proof': proof,
+                 'previous_hash': previous_hash
+                 }
+        self.chain.append(block)
+        return block
+    
+    def get_previous_block(self):
+        return self.chain[-1]
+    
+    def proof_of_work(self,previous_proof):
+        new_proof = 1
+        check_proof = False
+        while check_proof is False:
+            hash_operation = hashlib.sha256(str(new_proof**2 - previous_proof**2).encode()).hexdigest()
+            if hash_operation[:4]  == '0000':
+                check_proof = True
+            else:
+                new_proof += 1
+        return new_proof
+    
+    def hash(self,block):
+        encoded_block = json.dumps(block,sort_keys=True).encode()
+        return hashlib.sha256(encoded_block).hexdigest()
+    
+    def is_chain_valid(self,chain):
+        previous_block = chain[0]
+        block_index = 1
+        while block_index < len(chain):
+            block = chain[block_index]
+            if block['previous_hash'] != self.hash(previous_block):
+                return False
+            previous_proof = previous_block['proof']
+            proof = block['proof']
+            hash_operation = hashlib.sha256(str(proof**2 - previous_proof**2).encode()).hexdigest()
+            if hash_operation[:4]  != '0000':
+                return False
+            previous_block = block
+            block_index += 1
+        return True
+    
+# Mining the Blockchain
+
+app = Flask(__name__)
+app.config['JSONIFY_PRETTYPRINT_REGULAR'] = False
+
+blockchain = Blockchain()
+
+@app.route('/mine_block', methods=['GET'])
+def mine_block():
+    previous_block = blockchain.get_previous_block()
+    previous_proof = previous_block['proof']
+    proof = blockchain.proof_of_work(previous_proof)
+    previous_hash = blockchain.hash(previous_block)
+    block = blockchain.create_block(proof, previous_hash)
+    response = {'message': 'Congratulations, you just mined a block',
+                'index': block['index'],
+                 'timestamp': block['timestamp'],
+                'proof': block['proof'],
+                'previous_hash': block['previous_hash']}
+    return jsonify(response), 200
+
+@app.route('/get_chain', methods=['GET'])
+def get_chain():
+    response = {'chain':blockchain.chain,
+               'length':len(blockchain.chain)}
+    return jsonify(response), 200
+
+@app.route('/is_valid', methods=['GET'])
+def is_valid():
+    is_valid = blockchain.is_chain_valid(blockchain.chain)
+    if is_valid:
+        response = {'message':'The Blockchain is valid'}
+    else:
+        response = {'message':'The Blockchain is invalid'}
+    return jsonify(response),200
+
+app.run(host='0.0.0.0',port=5000)   
+            
+    
+        
+            
+        
+

README.md

@@ -21,9 +21,9 @@
 
 2. **Clone your fork:** Clone your forked repository to your local machine.
 
-    ```bash
-    git clone https://github.com/your-username/A-Z-Python-Projects.git
-    ```
+   ```bash
+   git clone https://github.com/your-username/A-Z-Python-Projects.git
+   ```
 
 3. **Choose your project:** Explore the project folders, pick a Python project that aligns with your interest and skill level.
 
@@ -41,15 +41,15 @@ We welcome contributions from developers of all skill levels. Follow these steps
 
 3. **Commit your changes:** Commit your changes to your branch.
 
-    ```bash
-    git commit -m "Merged and update README"
-    ```
+   ```bash
+   git commit -m "Merged and update README"
+   ```
 
 4. **Push your changes:** Push your branch to your forked repository on GitHub.
 
-    ```bash
-    git push origin feature/your-feature-name
-    ```
+   ```bash
+   git push origin feature/your-feature-name
+   ```
 
 5. **Create a Pull Request:** Go to the [A-Z-Python-Projects repository](https://github.com/Techiral/A-Z-Python-Projects/) on GitHub and click on the "New Pull Request" button. Select your branch, add a descriptive title and comments, and submit the Pull Request.
 
@@ -94,6 +94,7 @@ We appreciate the contributions from the following community members:
 - [Harsimran Singh](https://github.com/Harsimran-19)
 - [Ezhill Ragesh](https://github.com/ezhillragesh)
 - [Brunda Bharadwaj](https://github.com/brundabharadwaj/)
+- [Hemanth Singh](https://github.com/Hemanth11011)
 
 ---