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Python DES CBC encryption and decryption code demonstration

import binascii
from pyDes import des, CBC, PAD_PKCS5


def des_encrypt(s) :
    DES encrypted :param s: original string :return: encrypted string, hexadecimal ""
    secret_key = '20171117'
    iv = secret_key
    k = des(secret_key, CBC, iv, pad=None, padmode=PAD_PKCS5)
    en = k.encrypt(s, padmode=PAD_PKCS5)
    return binascii.b2a_hex(en)


def des_descrypt(s) :
    DES decryption :param s: encrypted string, hexadecimal :return: decrypted string """
    secret_key = '20171117'
    iv = secret_key
    k = des(secret_key, CBC, iv, pad=None, padmode=PAD_PKCS5)
    de = k.decrypt(binascii.a2b_hex(s), padmode=PAD_PKCS5)
    return de


str_en = des_encrypt('zx')
print(str_en)
str_de = des_descrypt(str_en)
print(str_de)
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Execute the Python code above and get the following output:

1dbbd4e9246ebffa
zx
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Java DES CBC encryption and decryption code demonstration

import javax.crypto.spec.IvParameterSpec;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;


public class Main {

    public static void main(String[] args) {
        String content="zx";
        String key = "20171117";

        System.out.println("Before encryption:" + content);
        byte[] encrypted = DES_CBC_Encrypt(content.getBytes(), key.getBytes());
        System.out.println("After encryption:" + byteToHexString(encrypted));

        byte[] decrypted = DES_CBC_Decrypt(encrypted, key.getBytes());
        System.out.println("After decryption:" + new String(decrypted));
    }

    public static byte[] DES_CBC_Encrypt(byte[] content, byte[] keyBytes) {
        try {
            DESKeySpec keySpec = new DESKeySpec(keyBytes);
            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
            SecretKey key = keyFactory.generateSecret(keySpec);

            Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
            cipher.init(Cipher.ENCRYPT_MODE, key, new IvParameterSpec(keySpec.getKey()));
            byte[] result = cipher.doFinal(content);
            return result;
        } catch (Exception e) {
            System.out.println("exception:" + e.toString());
        }
        return null;
    }

    private static byte[] DES_CBC_Decrypt(byte[] content, byte[] keyBytes) {
        try {
            DESKeySpec keySpec = new DESKeySpec(keyBytes);
            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
            SecretKey key = keyFactory.generateSecret(keySpec);

            Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
            cipher.init(Cipher.DECRYPT_MODE, key, new IvParameterSpec(keyBytes));
            byte[] result = cipher.doFinal(content);
            return result;
        } catch (Exception e) {
            System.out.println("exception:" + e.toString());
        }
        return null;
    }

    private static String byteToHexString(byte[] bytes) {
        StringBuffer sb = new StringBuffer(bytes.length);
        String sTemp;
        for (int i = 0; i < bytes.length; i++) {
            sTemp = Integer.toHexString(0xFF & bytes[i]);
            if (sTemp.length() < 2)
                sb.append(0);
            sb.append(sTemp.toUpperCase());
        }
        return sb.toString();
    }
}
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Execute the Java code above and output:

Before encryption: zx After encryption: 1DBBD4E9246EBFFA After decryption: zxCopy the code

Matters needing attention

There is also a library in Python, Crypto, which is also used for encryption, but the result of encryption is not the same as that of Java. This is a pit.

From Crypto.Cipher import DES import binascii import base64 # data-> key-> def des_decode(data, key): b_data = base64.b64decode(data) iv = key.encode() cipher = DES.new(key.encode(), iv,DES.MODE_CBC) decrypted = cipher.decrypt(b_data) decrypted.rstrip(b' ') return decrypted.decode() # # data-> encrypted string key-> def aes_encrypt(data, key): Cipher = DES. New (key.encode(),iv, Des.mode_cbc) # string to byte array b_data = data.encode() # ------ according to the 16 bits of its insufficiency space ---- block_size = des.block_size count = Len (b_data) # text = multiples of 16 add_count = block_size - (count % block_size) s_plaintext = data + (" * add_count) ---- b_plaintext = s_plaintext.encode() encrypted = cipher.encrypt(b_plaintext) # des encrypted return base64.b64encode(encrypted).decode()Copy the code