RSA 非对称加密之分段解密
前言：在上一篇文章我们讲到了加密与分段加密，这篇文章我们接着来看解密与分段解密。
一、非对称解密需要用到哪些库
- rsa
pip install rsa==4.8 - base64
python 自带无需安装
二、非对称解密步骤
- 加载私钥
- 预加密计算解密模值
- 解密/非对称解密
三、分对称解密步骤详解
-
加载私钥
方式一：#写死在py文件中 import rsa import base64 privkey = """ -----BEGIN RSA PRIVATE KEY----- MIIBOwIBAAJBAJBWZJsSrhwDmtjZkq0hsS0ZSa7JJPvo5gfybdHnRLuZa9jGwfBh sXFFCJYnZabjQLJ1oPbQ1f7jwbS1WDxI9FkCAwEAAQJABkvuiaFP/SLfH3SmZG0i 2I/Q2hImTeMEHfaiedS37wjwFCjtK12O73ZviLjtpeFyWHcoqEkAhxTvZZfpGNWs vQIjAMrsJdBGRb3IFktM6+JF6aHAsUPp2Py7tYo++R241U/kAm8CHwC2F1jyw0Lb o1v/t2dDq6U1/TbpcnfqUI5zzw6HubcCIi2LJM2DCCIZJ0/NOt/1GwOv0NlSQd4v bwZRLe5Kzq14mkcCHkmlQ7pbssy2U10nRkKeR2GAmhbszwcbsaGxGsVWHQIiE6tW fSyhJt5DtrAhwkbZwRqWFjovii5QSSzuBmFztnt8VA== -----END RSA PRIVATE KEY----- """ pubkey = """ -----BEGIN RSA PUBLIC KEY----- MEgCQQCQVmSbEq4cA5rY2ZKtIbEtGUmuyST76OYH8m3R50S7mWvYxsHwYbFxRQiW J2Wm40CydaD20NX+48G0tVg8SPRZAgMBAAE= -----END RSA PUBLIC KEY----- """ my_pubkey =rsa.PublicKey.load_pkcs1(pubkey) my_privkey=rsa.PrivateKey.load_pkcs1(privkey)方式二：
#从pem秘钥文件读取 import rsa import base64 with open(file="privkey.pem",mode="rb") as file: privkey = file.read() my_privkey = rsa.PrivateKey.load_pkcs1(keyfile=privkey) with open(file="pubkey.pem",mode="rb") as file: pubkey = file.read() my_pubkey = rsa.PublicKey.load_pkcs1(keyfile=pubkey) -
预加密计算解密模值
#模长计算公式 = 证书key位数/8 - 11 #证书key位数：一般是512、1024、2048，这个步骤可以问开发，也可以通过加密后密串长度来推算 #证书key位数：动态获取，加密串长度与证书位数对应关系：{'64':512,'128':1024,"512":2048} # max_encode_len: 加密模长(就是加密分片长度) # max_decode_len: 解密模长(就是解密分片长度) #代码演示 def choice_channel(): msg = "test".encode() models_dict={'64':512,'128':1024,"512":2048} encrypt_msg = rsa.encrypt(message=msg, pub_key=self.pubkey) max_decode_len = len(encrypt_msg) key_size = models_dict['{}'.format(max_decode_len)] max_encode_len = int(key_size/8-11) print("加密模长：",max_encode_len) return max_encode_len,max_decode_len -
解密/非对称解密
import rsa import base64 class MyRsa: def __init__(self): privkey = """ -----BEGIN RSA PRIVATE KEY----- MIIBOwIBAAJBAJBWZJsSrhwDmtjZkq0hsS0ZSa7JJPvo5gfybdHnRLuZa9jGwfBh sXFFCJYnZabjQLJ1oPbQ1f7jwbS1WDxI9FkCAwEAAQJABkvuiaFP/SLfH3SmZG0i 2I/Q2hImTeMEHfaiedS37wjwFCjtK12O73ZviLjtpeFyWHcoqEkAhxTvZZfpGNWs vQIjAMrsJdBGRb3IFktM6+JF6aHAsUPp2Py7tYo++R241U/kAm8CHwC2F1jyw0Lb o1v/t2dDq6U1/TbpcnfqUI5zzw6HubcCIi2LJM2DCCIZJ0/NOt/1GwOv0NlSQd4v bwZRLe5Kzq14mkcCHkmlQ7pbssy2U10nRkKeR2GAmhbszwcbsaGxGsVWHQIiE6tW fSyhJt5DtrAhwkbZwRqWFjovii5QSSzuBmFztnt8VA== -----END RSA PRIVATE KEY----- """ pubkey = """ -----BEGIN RSA PUBLIC KEY----- MEgCQQCQVmSbEq4cA5rY2ZKtIbEtGUmuyST76OYH8m3R50S7mWvYxsHwYbFxRQiW J2Wm40CydaD20NX+48G0tVg8SPRZAgMBAAE= -----END RSA PUBLIC KEY----- """ #加载秘钥对象 self.pubkey =rsa.PublicKey.load_pkcs1(pubkey) self.privkey=rsa.PrivateKey.load_pkcs1(privkey) #预加密计算模长 self.max_encode_len,self.max_decode_len = self.choice_channel() #预加密，获取模长 def choice_channel(self): msg = "test".encode() models_dict={'64':512,'128':1024,"512":2048} #加密，获取bytes类型的秘钥长度 encrypt_msg = rsa.encrypt(message=msg, pub_key=self.pubkey) max_decode_len = len(encrypt_msg) print("解密模长：", max_decode_len) key_size = models_dict['{}'.format(max_decode_len)] max_encode_len = int(key_size/8-11) print("加密模长：",max_encode_len) return max_encode_len,max_decode_len #解密 def decode_string(self,encrypt_msg): encrypt_msg = base64.b64decode(encrypt_msg) decrypt_str = rsa.decrypt(crypto=encrypt_msg,priv_key=self.privkey) new_decrypt_str=decrypt_str.decode() print("解密结果：",new_decrypt_str) return new_decrypt_str #分段解密 def section_decode(self,msg): decode_str = msg.encode() decode_str = base64.b64decode(decode_str) if len(decode_str) <= self.max_decode_len: print("不需要分段解密") decode_string = self.decode_string(encrypt_msg=msg) print("解密结果：",decode_string) return decode_string else: print("需要分段加密") decode_text=[] for i in range(0,len(decode_str),self.max_decode_len): section_text = decode_str[i:(i + self.max_decode_len)] decrypt_str = rsa.decrypt(crypto=section_text, priv_key=self.privkey) decode_text.append(decrypt_str) decode_byte = b"".join(decode_text) decode_string = decode_byte.decode() print("解密结果：",decode_string) return decode_string
四、完整代码
import rsa
import base64
class MyRsa:
def __init__(self):
privkey = """
-----BEGIN RSA PRIVATE KEY-----
MIIBOwIBAAJBAJBWZJsSrhwDmtjZkq0hsS0ZSa7JJPvo5gfybdHnRLuZa9jGwfBh
sXFFCJYnZabjQLJ1oPbQ1f7jwbS1WDxI9FkCAwEAAQJABkvuiaFP/SLfH3SmZG0i
2I/Q2hImTeMEHfaiedS37wjwFCjtK12O73ZviLjtpeFyWHcoqEkAhxTvZZfpGNWs
vQIjAMrsJdBGRb3IFktM6+JF6aHAsUPp2Py7tYo++R241U/kAm8CHwC2F1jyw0Lb
o1v/t2dDq6U1/TbpcnfqUI5zzw6HubcCIi2LJM2DCCIZJ0/NOt/1GwOv0NlSQd4v
bwZRLe5Kzq14mkcCHkmlQ7pbssy2U10nRkKeR2GAmhbszwcbsaGxGsVWHQIiE6tW
fSyhJt5DtrAhwkbZwRqWFjovii5QSSzuBmFztnt8VA==
-----END RSA PRIVATE KEY-----
"""
pubkey = """
-----BEGIN RSA PUBLIC KEY-----
MEgCQQCQVmSbEq4cA5rY2ZKtIbEtGUmuyST76OYH8m3R50S7mWvYxsHwYbFxRQiW
J2Wm40CydaD20NX+48G0tVg8SPRZAgMBAAE=
-----END RSA PUBLIC KEY-----
"""
#加载秘钥对象
self.pubkey =rsa.PublicKey.load_pkcs1(pubkey)
self.privkey=rsa.PrivateKey.load_pkcs1(privkey)
#预加密计算模长
self.max_encode_len,self.max_decode_len = self.choice_channel()
#预加密，获取模长
def choice_channel(self):
msg = "test".encode()
models_dict={'64':512,'128':1024,"512":2048}
encrypt_msg = rsa.encrypt(message=msg, pub_key=self.pubkey)
max_decode_len = len(encrypt_msg)
print("解密模长：", max_decode_len)
key_size = models_dict['{}'.format(max_decode_len)]
max_encode_len = int(key_size/8-11)
print("加密模长：",max_encode_len)
return max_encode_len,max_decode_len
#加密
def encode_string(self,string):
msg = string.encode()
encrypt_msg = rsa.encrypt(message=msg,pub_key=self.pubkey)
encrypt_msg = base64.b64encode(encrypt_msg)
encrypt_msg = encrypt_msg.decode()
return encrypt_msg
#解密
def decode_string(self,encrypt_msg):
encrypt_msg = base64.b64decode(encrypt_msg)
decrypt_str = rsa.decrypt(crypto=encrypt_msg,priv_key=self.privkey)
new_decrypt_str=decrypt_str.decode()
print("解密结果：",new_decrypt_str)
return new_decrypt_str
#分段加密
def section_encode(self,msg):
if len(msg) <= self.max_encode_len:
print("不需要进行分段加密")
encode_string = self.encode_string(string=msg)
print("加密结果：", encode_string)
return encode_string
else:
print("需要分段加密")
encode_text = []
for i in range(0,len(msg),self.max_encode_len):
#需要加密的字符串进行切片
section_text = msg[i:(i+self.max_encode_len)]
section_text = section_text.encode()
#分段加密
encode_str = rsa.encrypt(message=section_text, pub_key=self.pubkey)
encode_text.append(encode_str)
#拼接加密后的bytes数据
encode_bytes = b"".join(encode_text)
encode_string = base64.b64encode(s=encode_bytes)
encode_string = encode_string.decode()
print("分段加密结果：",encode_string)
return encode_string
#分段解密
def section_decode(self,msg):
decode_str = msg.encode()
decode_str = base64.b64decode(decode_str)
if len(decode_str) <= self.max_decode_len:
print("不需要分段解密")
decode_string = self.decode_string(encrypt_msg=msg)
print("解密结果：",decode_string)
return decode_string
else:
print("需要分段加密")
decode_text=[]
for i in range(0,len(decode_str),self.max_decode_len):
section_text = decode_str[i:(i + self.max_decode_len)]
decrypt_str = rsa.decrypt(crypto=section_text, priv_key=self.privkey)
decode_text.append(decrypt_str)
decode_byte = b"".join(decode_text)
decode_string = decode_byte.decode()
print("解密结果：",decode_string)
return decode_string
if __name__ == '__main__':
cl = MyRsa()
test_str = "dsdffdsdffasdfasdfdsdffasdfasdfasdfdsdffasdfasdfdsdffasdfasdfdsdffasdfasdfasdf"
res = cl.section_encode(msg=test_str)
cl.section_decode(msg=res)
运行结果：
解密模长： 64
加密模长： 53
需要分段加密
分段加密结果： Ud7Pp5w2gz5gFKv0rykptx29+ID7IfrH7Gszkiz3W/QedQM0kv4RDGVWduUEkrO+exh3KC380pTw3/VwHPtTJUzi94321WXMwwwxKAx4eGOLrXfFAaEBjAaHvwNAfavV1+/tV9+QcISBvs+wb0CvQo2Mmh9MBjACP9e/PVZxj1I=
需要分段加密
解密结果： dsdffdsdffasdfasdfdsdffasdfasdfasdfdsdffasdfasdfdsdffasdfasdfdsdffasdfasdfasdf