python implementation of AES bidirectional symmetric encryption and decryption and usage analysis
- 2020-05-30 20:30:32
This article illustrates the implementation and usage of AES bidirectional symmetric encryption and decryption by python. I will share it with you for your reference as follows:
Advanced encryption standard (Advanced Encryption Standard, AES), also known as Rijndael encryption in cryptography, is a block encryption standard adopted by the United States federal government. This standard, which replaces the original DES, has been analyzed by multiple parties and is widely used around the world. After a 5-year selection process, the advanced encryption standard was issued by the U.S. national institute of standards and technology (NIST) on FIPS PUB 197 on November 26, 2001, and became an effective standard on May 26, 2002. In 2006, advanced encryption standards became one of the most popular algorithms for symmetric key encryption.
AES is just a basic algorithm. There are several patterns to implement AES. The CBC mode is used by TLS (the encryption standard of https) and IPSec (the encryption standard of win) for its security. Simply put, CBC USES a password and salt (which is disruptive) to produce key and iv using a fixed algorithm (md5). It then encrypts (plaintext) and decrypts (ciphertext) with key and iv (initial vector, encryption block 1 plaintext).
The following is an example of encryption and decryption of AES implemented by python. Here, CBC mode is adopted and pycrypto is used. The module
pip install Crypto pip install binascii
#!/usr/bin/env python # -*- coding:utf-8 -*- #@author: rui.xu # Used here pycrypto library # According to the method :easy_install pycrypto from Crypto.Cipher import AES from binascii import b2a_hex, a2b_hex class prpcrypt(): def __init__(self,key): self.key = key self.mode = AES.MODE_CBC # Encryption function if text insufficient 16 The bit is complemented by a space 16 position # If more than 16 At that time is not 16 A multiple of theta, so let's make it up to theta 16 Multiples. def encrypt(self,text): cryptor = AES.new(self.key,self.mode,b'0000000000000000') # Here is the key key The length must be 16 ( AES-128 ) , #24 ( AES-192 ) , or 32 ( AES-256 ) Bytes The length of the # At present AES-128 Sufficient for current use length = 16 count = len(text) if count < length: add = (length-count) #\0 backspace text = text + ('\0' * add) elif count > length: add = (length-(count % length)) text = text + ('\0' * add) self.ciphertext = cryptor.encrypt(text) # because AES The string you get when you encrypt it is not 1 It is ascii Character set, output to terminal or save may have problems # So here 1 Converts the encrypted string to 16 Base string return b2a_hex(self.ciphertext) # After decryption, remove the blank complement strip() To get rid of def decrypt(self,text): cryptor = AES.new(self.key,self.mode,b'0000000000000000') plain_text = cryptor.decrypt(a2b_hex(text)) return plain_text.rstrip('\0') if __name__ == '__main__': pc = prpcrypt('keyskeyskeyskeys') # Initialization key import sys e = pc.encrypt(sys.argv) # encryption d = pc.decrypt(e) # decryption print " encryption :",e print " decryption :",d
ValueError: IV must be 16 bytes long windows will report this error by default,
cryptor = AES.new(self.key,self.mode,b'0000000000000000')
I'm going to instantiate it and then I'm going to add Ok to it
PS: about encryption and decryption interested friends can also refer to the website online tools:
MD5 online encryption tool:
Thunderbolt, express and whirlwind encryption/decryption tools:
Online hash/hash algorithm encryption tool:
MD5/hash/ SHA-1 / SHA-2 / SHA-256 / SHA-512 / SHA-3 / RIPEMD-160 encryption tools:
Online sha1 sha224 / sha256 sha384 / sha512 encryption tools:
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I hope this article is helpful to you in Python programming.