Java 32个字符的字符串如何变成46个字节?
我正试图学习一些加密技术,但不知怎的,我遇到了一个问题。我想对文本(比如字符串“password”)执行某种AES加密。我将ff代码作为我的源代码:Java 32个字符的字符串如何变成46个字节?,java,string,utf-8,ascii,Java,String,Utf 8,Ascii,我正试图学习一些加密技术,但不知怎的,我遇到了一个问题。我想对文本(比如字符串“password”)执行某种AES加密。我将ff代码作为我的源代码: import java.io.UnsupportedEncodingException; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import javax.crypto.spec.SecretKeySpec; import
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));
}
}
import java.io.UnsupportedEncodingException;
导入java.security.MessageDigest;
导入java.security.NoSuchAlgorithmException;
导入javax.crypto.spec.SecretKeySpec;
导入javax.crypto.spec.IvParameterSpec;
导入javax.crypto.Cipher;
公共类AES{
静态字符串IV=“fedcba9876543210”;
静态字符串plaintext=“password”/*注意空填充*/
//静态字符串加密密钥=“0123456789abcdef0123456789abcdef”;
静态字符串encKey=“CF6000C7452F9487CC03CD721A3F18482E43CDC37C380E062193C489F968D04”;
静态字符串encryptionKey=“”;
公共静态void main(字符串[]args){
试一试{
System.out.print(明文.length()+“\n”);
if(明文.length()<16){
int pad=16-纯文本.length();
字符串重复=新字符串(新字符[pad])。替换(“\0”,“\0”);
纯文本=纯文本+重复;
}
System.out.println(“==Java=”);
System.out.println(“纯:+纯文本);
System.out.print(明文.length()+“\n”);
encryptionKey=hexToAscii(encKey);
//encryptionKey=“0123456789abcdef0123456789abcdef”;
字节[]密码=加密(明文,加密密钥);
字符串a=byteArrayToHex(密码);
系统输出打印(a+“\n”);
系统输出打印(“密码:”);
对于(inti=0;i,不要假设字符串中的一个字符占用一个字节
在大多数编码中,这是正确的,仅适用于小于128的字符
由于hexToAscii
返回的字符串的字符范围为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字符串。字符串代表文本;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
应返回字节数组,而encrypt
应只需在明文上调用getBytes
。切勿假设启用该选项字符串中的e字符占用一个字节
在大多数编码中,这是正确的,仅适用于小于128的字符
由于hexToAscii
返回的字符串的字符范围为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字符串。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
应返回字节数组,而encrypt
应只需在明文上调用getBytes
。调用get的是什么Bytes()
你在说什么?你有几个。哪种编码?对getBytes()的哪种调用
你说的是什么?你有几种。哪种编码?事实上,一个Java字符串是UTF-16,每个字符两个字节。根据十六进制值,它们可能不会转换为单个值。例如,第一个十六进制值cf是unicode字符的拉丁文大写字母l,带有diaeresis,Ï。这将转换为两个字节的UTF-8值C3 8F。谢谢。。。我最终将编码改为ISO-8859-1@user1397215那么您的代码仍然是错误的;正如我所说的,除了纯文本之外,您不应该使用getBytes
。事实上,Java字符串是UTF-16,每个字符两个字节。根据十六进制值,它们可能不会转换为单个值。例如,第一个十六进制值cf是uni编码字符拉丁文大写字母l,带分音符,Ï。这将转换为两个字节的UTF-8值C3 8F。谢谢…我最终将编码改为ISO-8859-1@user1397215那么您的代码仍然是错误的;正如我所说的,除了纯文本之外,您不应该使用getBytes
。