1. hashlib库

利用python的hashlib库，可以实现使用sha256、md5等加密算法生成哈希值。

1.1 hash对象

hash对象	描述
md5()	md5算法加密
sha1()	sha1算法加密
sha224()	sha224算法加密
sha256()	sha256算法加密
sha384()	sha384算法加密
sha512()	sha512算法加密

1.2 hash对象的方法

方法	描述
copy()	复制一个hash对象
digest()	返回bytes类型的hash值
hexdigest()	返回str类型的hash值
update()	传入编码后的字符串

2. 使用sha256生成哈希值

2.1 生成字符串的哈希值

from hashlib import sha256
 
def generate_sha256_hashCode(plainText):
    plainTextBytes = plainText.encode('utf-8') # 字符串在哈希之前，需要编码
    encryptor = sha256()      
    encryptor.update(plainTextBytes)   
    hashCode = encryptor.hexdigest() 
    print(hashCode)
 
if __name__ == "__main__":
    generate_sha256_hashCode('123')

运行结果：

a665a45920422f9d417e4867efdc4fb8a04a1f3fff1fa07e998e86f7f7a27ae3

2.2 生成文件的哈希值

from hashlib import sha256
 
def generate_sha256_hashCode(filePath):
    with open(filePath, encoding="utf-8") as f:
        plainText = f.read()
    plainTextBytes = plainText.encode('utf-8')
    encryptor = sha256()   
    encryptor.update(plainTextBytes) 
    hashCode = encryptor.hexdigest() 
    print(hashCode)
 
if __name__ == "__main__":
    generate_sha256_hashCode('test.txt')

3. 使用md5生成哈希值

使用md5或其他算法，同sha256，只需要改动以下两行即可：

from hashlib import 算法名
encryptor = 算法名()

3.1 生成字符串的哈希值

from hashlib import md5
 
def generate_md5_hashCode(plainText):
    plainTextBytes = plainText.encode('utf-8') 
    encryptor = md5()   
    encryptor.update(plainTextBytes) 
    hashCode = encryptor.hexdigest() 
    print(hashCode)
 
if __name__ == "__main__":
    generate_md5_hashCode('123')

运行结果：

202cb962ac59075b964b07152d234b70

3.2 生成文件的哈希值

from hashlib import md5
 
def generate_md5_hashCode(filePath):
    with open(filePath, encoding="utf-8") as f:
        plainText = f.read()
    plainTextBytes = plainText.encode('utf-8')
    encryptor = md5()   
    encryptor.update(plainTextBytes) 
    hashCode = encryptor.hexdigest() 
    print(hashCode)
 
if __name__ == "__main__":
    generate_md5_hashCode('test.txt')