我正在尝试学习一些加密技术但不知何故我遇到了问题。我想对文本执行某种AES加密(比如字符串“password”)。我有ff代码作为我的来源:
import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import javax.crypto.spec.SecretKeySpec;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.Cipher;
public class AES {
static String IV = "fedcba9876543210";
static String plaintext = "password"; /*Note null padding*/
//static String encryptionKey = "0123456789abcdef0123456789abcdef";
static String encKey = "cf6000c7452f9487cc03cd721a3f18482e43cdcc37c380e062193c489f968d04";
static String encryptionKey = "";
public static void main(String [] args) {
try {
System.out.print(plaintext.length() + "\n");
if (plaintext.length() < 16) {
int pad = 16 - plaintext.length();
String repeated = new String(new char[pad]).replace("\0", "\0");
plaintext = plaintext + repeated;
}
System.out.println("==Java==");
System.out.println("plain: " + plaintext);
System.out.print(plaintext.length() + "\n");
encryptionKey = hexToAscii(encKey);
//encryptionKey = "0123456789abcdef0123456789abcdef";
byte[] cipher = encrypt(plaintext, encryptionKey);
String a = byteArrayToHex(cipher);
System.out.print(a + "\n");
System.out.print("cipher: ");
for (int i=0; i<cipher.length; i++)
System.out.print(new Integer(cipher[i])+" ");
System.out.println("");
String decrypted = decrypt(cipher, encryptionKey);
System.out.println("decrypt: " + decrypted);
} catch (Exception e) {
e.printStackTrace();
}
}
public static byte[] encrypt(String plainText, String string) throws Exception {
//System.out.println("encrypting" + encryptionKey.length());
// Check length, in characters
System.out.println("Length of string is " + string.length()); // prints "11"
// Check encoded sizes
final byte[] utf8Bytes = string.getBytes("UTF-8");
System.out.println(utf8Bytes.length); // prints "11"
final byte[] utf16Bytes= string.getBytes("UTF-16");
System.out.println(utf16Bytes.length); // prints "24"
final byte[] utf32Bytes = string.getBytes("UTF-32");
System.out.println(utf32Bytes.length); // prints "44"
final byte[] isoBytes = string.getBytes("ISO-8859-1");
System.out.println(isoBytes.length); // prints "11"
final byte[] winBytes = string.getBytes("CP1252");
System.out.println(winBytes.length); // prints "11"
Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
System.out.println("enc 2");
SecretKeySpec key = new SecretKeySpec(encryptionKey.getBytes("UTF-8"), "AES");
System.out.println("enc 3");
cipher.init(Cipher.ENCRYPT_MODE, key,new IvParameterSpec(IV.getBytes("UTF-8")));
System.out.println("enc 4");
return cipher.doFinal(plainText.getBytes("UTF-8"));
}
public static String hexToAscii(String s) {
int n = s.length();
StringBuilder sb = new StringBuilder(n / 2);
for (int i = 0; i < n; i += 2) {
char a = s.charAt(i);
char b = s.charAt(i + 1);
sb.append((char) ((hexToInt(a) << 4) | hexToInt(b)));
}
return sb.toString();
}
public static String decrypt(byte[] cipherText, String encryptionKey) throws Exception{
Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
SecretKeySpec key = new SecretKeySpec(encryptionKey.getBytes("UTF-8"), "AES");
cipher.init(Cipher.DECRYPT_MODE, key,new IvParameterSpec(IV.getBytes("UTF-8")));
return new String(cipher.doFinal(cipherText),"UTF-8");
}
public static String byteArrayToHex(byte[] a) {
StringBuilder sb = new StringBuilder(a.length * 2);
for(byte b: a)
sb.append(String.format("%02x", b & 0xff));
return sb.toString();
}
private static int hexToInt(char ch) {
if ('a' <= ch && ch <= 'f') { return ch - 'a' + 10; }
if ('A' <= ch && ch <= 'F') { return ch - 'A' + 10; }
if ('0' <= ch && ch <= '9') { return ch - '0'; }
throw new IllegalArgumentException(String.valueOf(ch));
}
}
字符串"cf6000c7452f9487cc03cd721a3f18482e43cdcc37c380e062193c489f968d04"
是64个十六进制数字的序列,我希望在转换为字符串时相当于32个字符。使用这32个字符作为我的密钥,我无法进行上面代码中所示的加密,因为对密钥的getBytes的调用以某种方式将其设置为46字节。
在长度为32个字符的普通字符串(非十六进制)(例如0123456789abcdef0123456789abcdef
)上,整个加密过程用作使用此字符串调用getBytes,因为密钥的长度为32个字节。
有什么想法吗?理想情况下,我想知道如何使用第一个十六进制数字序列(要转换为字符串)作为密钥来加密文本。我已经成功地在python中执行此操作,但是这可以在Java中使用吗?
答案 0 :(得分:4)
永远不要假设String中的一个字符占用一个字节。
确实如此,在大多数编码中,仅适用于小于128的字符。
由于hexToAscii
返回的字符串的字符数为128-255,因此这些字符将被编码为多个字节。
解决方案不是将密钥视为String。字符串用于文本;加密密钥不是文本,而是字节序列。将加密密钥存储在字节数组中。 hexToAscii
应该返回一个字节数组,而encrypt
只需要在明文上调用getBytes
。