Usually, a common problem occurs when using 3DES to encrypt and decrypt strings in Java, resulting in the inability to successfully decrypt the ciphertext. Return the original string. This article provides a simple code example that can encrypt and decrypt a string and restore it to the original string.
In the original question, the code given has the following error:
The corrected code is as follows:
import java.security.MessageDigest; import java.util.Arrays; import javax.crypto.Cipher; import javax.crypto.SecretKey; import javax.crypto.spec.IvParameterSpec; import javax.crypto.spec.SecretKeySpec; public class TripleDESTest { public static void main(String[] args) throws Exception { String text = "kyle boon"; byte[] codedtext = new TripleDESTest().encrypt(text); String decodedtext = new TripleDESTest().decrypt(codedtext); System.out.println(codedtext); // this is a byte array, you'll just see a reference to an array System.out.println(decodedtext); // This correctly shows "kyle boon" } public byte[] encrypt(String message) throws Exception { final MessageDigest md = MessageDigest.getInstance("md5"); final byte[] digestOfPassword = md.digest("HG58YZ3CR9" .getBytes("utf-8")); final byte[] keyBytes = Arrays.copyOf(digestOfPassword, 24); for (int j = 0, k = 16; j < 8;) { keyBytes[k++] = keyBytes[j++]; } final SecretKey key = new SecretKeySpec(keyBytes, "DESede"); final IvParameterSpec iv = new IvParameterSpec(new byte[8]); final Cipher cipher = Cipher.getInstance("DESede/CBC/PKCS5Padding"); cipher.init(Cipher.ENCRYPT_MODE, key, iv); final byte[] plainTextBytes = message.getBytes("utf-8"); final byte[] cipherText = cipher.doFinal(plainTextBytes); final String encodedCipherText = new sun.misc.BASE64Encoder() .encode(cipherText); return cipherText; } public String decrypt(byte[] message) throws Exception { final MessageDigest md = MessageDigest.getInstance("md5"); final byte[] digestOfPassword = md.digest("HG58YZ3CR9" .getBytes("utf-8")); final byte[] keyBytes = Arrays.copyOf(digestOfPassword, 24); for (int j = 0, k = 16; j < 8;) { keyBytes[k++] = keyBytes[j++]; } final SecretKey key = new SecretKeySpec(keyBytes, "DESede"); final IvParameterSpec iv = new IvParameterSpec(new byte[8]); final Cipher decipher = Cipher.getInstance("DESede/CBC/PKCS5Padding"); decipher.init(Cipher.DECRYPT_MODE, key, iv); final byte[] encData = new sun.misc.BASE64Decoder().decodeBuffer(message); final byte[] plainText = decipher.doFinal(encData); return new String(plainText, "UTF-8"); } }
After using the correct Base64 encoding and decoding steps, the code can successfully 3DES encrypt and decrypt the string and ensure The decrypted result is correctly restored to the original string.
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