走进Python Hash函数的魔幻世界：解密哈希算法与防碰撞技术

# 使用hash()函数计算哈希值
hash_value1 = hash(42)
hash_value2 = hash("Hello, Python!")
hash_value3 = hash((1, 2, 3))

print(f"Hash value of 42: {hash_value1}")
print(f"Hash value of 'Hello, Python!': {hash_value2}")
print(f"Hash value of (1, 2, 3): {hash_value3}")

import hashlib

data = "Hello, MD5!"
# 创建MD5对象
md5_obj = hashlib.md5()
# 更新哈希对象以使用字符串
md5_obj.update(data.encode())
# 获取MD5哈希值
md5_hash = md5_obj.hexdigest()

print(f"MD5 Hash of '{data}': {md5_hash}")

data = "Hello, SHA-256!"
# 创建SHA-256对象
sha256_obj = hashlib.sha256()
# 更新哈希对象以使用字符串
sha256_obj.update(data.encode())
# 获取SHA-256哈希值
sha256_hash = sha256_obj.hexdigest()

print(f"SHA-256 Hash of '{data}': {sha256_hash}")

# 创建一个字典
person = {
    "name": "John Doe",
    "age": 30,
    "email": "john@example.com"
}

# 添加新的键值对
person["city"] = "New York"

# 获取键对应的值
print("Name:", person["name"])
print("Age:", person["age"])
print("Email:", person["email"])
print("City:", person.get("city", "City not found"))

# 删除键值对
del person["email"]

# 检查键是否存在
if "email" in person:
    print("Email found.")
else:
    print("Email not found.")

import hashlib

def calculate_hash(data):
    # 创建SHA-256对象
    sha256_obj = hashlib.sha256()
    # 更新哈希对象以使用数据
    sha256_obj.update(data)
    # 获取SHA-256哈希值
    return sha256_obj.digest()

    # 原始数据
original_data = b"Hello, Hash!"
# 计算原始数据的哈希值
original_hash = calculate_hash(original_data)

# 模拟数据传输或存储过程中数据被篡改
tampered_data = b"Hello, Tampered Hash!"
# 计算篡改后数据的哈希值
tampered_hash = calculate_hash(tampered_data)

# 对比哈希值
if original_hash == tampered_hash:
    print("Data integrity verified: Data is unchanged.")
else:
    print("Data integrity compromised: Data has been tampered with.")

# 创建一个哈希集合
fruits = {"apple", "banana", "orange", "apple", "grape"}
print("Fruits:", fruits)  # 输出：{'orange', 'banana', 'grape', 'apple'}

import hashlib

def hash_password(password):
    # 创建SHA-256对象
    sha256_obj = hashlib.sha256()
    # 更新哈希对象以使用密码
    sha256_obj.update(password.encode())
    # 获取SHA-256哈希值
    return sha256_obj.hexdigest()

    # 用户注册时设置密码
user_password = "my_secret_password"
hashed_password = hash_password(user_password)

# 模拟登录验证
input_password = input("Enter your password: ")
input_hashed_password = hash_password(input_password)

if input_hashed_password == hashed_password:
    print("Login successful.")
else:
    print("Invalid password. Please try again.")

import hashlib

def calculate_file_hash(file_path):
    # 创建SHA-256对象
    sha256_obj = hashlib.sha256()

    # 以二进制方式读取文件内容，避免文本编码问题
    with open(file_path, "rb") as file:
        while chunk := file.read(8192):  # 每次读取8KB数据
            sha256_obj.update(chunk)

            # 获取文件的SHA-256哈希值
    return sha256_obj.hexdigest()

def is_file_duplicate(file_path, known_hashes):
    file_hash = calculate_file_hash(file_path)
    return file_hash in known_hashes

    # 已知的Hash值集合，用于存储之前上传文件的Hash值
known_hashes = set()

# 假设用户上传了两个文本文件
file1_path = "path/to/uploaded_file1.txt"
file2_path = "path/to/uploaded_file2.txt"

# 检查文件1是否重复
if is_file_duplicate(file1_path, known_hashes):
    print("File 1 is a duplicate.")
else:
    print("File 1 is unique.")
    known_hashes.add(calculate_file_hash(file1_path))

    # 检查文件2是否重复
if is_file_duplicate(file2_path, known_hashes):
    print("File 2 is a duplicate.")
else:
    print("File 2 is unique.")
    known_hashes.add(calculate_file_hash(file2_path))