如何解码AES-256/CBC/ZeroBytePadding加密对象
我是Java密码学的新手。我提供了以下PHP代码来解密AES-256/CBC/ZeroBytePadding加密对象。如何解码AES-256/CBC/ZeroBytePadding加密对象
function decrypt($key, $data)
{
if (!in_array(strlen($key), array(32, 48, 64)))
{
throw new Exception("Invalid key");
}
$key_hex = pack('H*', $key);
$iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);
$ciphertext = base64_decode($data);
# retrieves the IV, iv_size should be created using mcrypt_get_iv_size()
$iv_dec = substr($ciphertext, 0, $iv_size);
# retrieves the cipher text (everything except the $iv_size in the front)
$ciphertext_dec = substr($ciphertext, $iv_size);
# may remove 00h valued characters from end of plain text
$result = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key_hex, $ciphertext_dec, MCRYPT_MODE_CBC, $iv_dec);
return $result;
}
我需要在java中做同样的事情。经过大量的搜索我做了以下代码:
public String decrypt(byte key[], String encrypted)
throws GeneralSecurityException {
if (key.length != 32 || key.length != 48 || key.length != 64) {
throw new IllegalArgumentException("Invalid key size.");
}
byte[] ciphertextBytes = Base64.decodeBase64(encrypted.getBytes());
// Need to find the IV length here. I am using 16 here
IvParameterSpec iv = new IvParameterSpec(ciphertextBytes, 0, 16);
ciphertextBytes = Arrays.copyOfRange(ciphertextBytes, 16,
ciphertextBytes.length);
SecretKeySpec skeySpec = new SecretKeySpec(key, "AES");
Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
cipher.init(Cipher.DECRYPT_MODE, skeySpec, iv);
byte[] original = cipher.doFinal(ciphertextBytes);
// remove zero bytes at the end
int lastLength = original.length;
for (int i = original.length - 1; i > original.length - 16; i--) {
if (original[i] == (byte) 0) {
lastLength--;
} else {
break;
}
}
return new String(original, 0, lastLength);
}
但我需要找到这里的IV长度。在PHP中,他们使用: $ iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128,MCRYPT_MODE_CBC); 如何在java中实现它?有人可以帮我吗?
我打电话的方法是这样的:在CBC模式
public static void main(String args[]) {
String key = "F5D4471791B79B6360C1EFF4A76250C1D7E5C23F5E4C3C43893B6CCAA796E307";
String encrypted = "F4N8SvpF1zgyMnQKwLlX\\/Dfgsj4kU58pg3kaSrt+AJt9D7\\/3vAfngegtytAdCUwwkQ2nxj8PVABRy0aaeBfsJN9n2Ltco6oPjdcmx8eOI";
try {
String decrypted = decrypt(Hex.decodeHex(key.toCharArray()), encrypted);
System.out.println(decrypted);
} catch (GeneralSecurityException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
一种IV为AES(Rijndael算法-128)具有总是大小作为块,这是16个字节或128位相同。如果您继续使用CBC模式,那么您可以对该值进行硬编码或使用Cipher#getBlockSize()
。
如果您想使用AES-256,则需要为您的JRE/JDK(Link for Java 8)安装Unlimited Strength策略文件。 AES-128可以不加修改地使用,但美国的出口限制要求你自己启用更高的密钥。
答案:在Artjom B的帮助下,我创建了解密AES-256/CBC/ZeroBytePadding加密字符串的代码。我将这张贴发布给需要帮助的其他人。
1.首先,您必须为您的JDK版本下载Java加密扩展(JCE)无限强度管辖策略。
2.将zip文件解压&把local_policy.jar &的US_export_policy.jar路径/ JDK路径/ JRE/lib/security中。这是必需的,因为我的密钥是64字节。 AES需要16/24/32字节的密钥。
3.复制粘贴我的代码&根据您的要求更改它:P。
import java.security.GeneralSecurityException;
import java.util.Arrays;
import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import org.apache.commons.codec.DecoderException;
import org.apache.commons.codec.binary.Hex;
import org.apache.commons.codec.binary.Base64;
public class Decryption {
public static void main(String args[]) {
//I have changed the original key. So mere copy pasting may not work. Put your key here.
String key = "FfDaaaaaaa444aaaa7aaEFF4A76efaaaaaE5C23F5E4C3adeaaaaaaCAA796E307";
String encrypted = "8AQ8SvpF1zgyNyxKwLlX\\/cGzwLE5skU58pg3kaSrt+AJt9D7\\/3vaNRPZISIKMdCUwwkQ2nxj8PVABRy0aaeBfsJN9n2Ltco6oPjdcmx8eOI";
String decrypted = "";
try {
try {
decrypted = decrypt(Hex.decodeHex(key.toCharArray()), encrypted);
} catch (DecoderException e) {
e.printStackTrace();
}
System.out.println(decrypted);
} catch (GeneralSecurityException e) {
e.printStackTrace();
}
}
public static String decrypt(byte key[], String encrypted)
throws GeneralSecurityException {
/*
* if (key.length != 32 || key.length != 48 || key.length != 64) { throw
* new IllegalArgumentException("Invalid key size."); }
*/
byte[] ciphertextBytes = Base64.decodeBase64(encrypted.getBytes());
IvParameterSpec iv = new IvParameterSpec(ciphertextBytes, 0, 16);
ciphertextBytes = Arrays.copyOfRange(ciphertextBytes, 16,
ciphertextBytes.length);
SecretKeySpec skeySpec = new SecretKeySpec(key, "AES");
Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
cipher.init(Cipher.DECRYPT_MODE, skeySpec, iv);
byte[] original = cipher.doFinal(ciphertextBytes);
// Remove zero bytes at the end.
int lastLength = original.length;
for (int i = original.length - 1; i > original.length - 16; i--) {
if (original[i] == (byte) 0) {
lastLength--;
} else {
break;
}
}
return new String(original, 0, lastLength);
}
}
感谢@Artjom B.您的帮助&专长:)。
请不要编辑您的问题以包含答案。您可以发布自己的问题的答案。完成之后,请将您的问题回滚至修订4. –
您问题中的答案使用的密钥不是有效的十六进制编码,因为它包含0-9以外的字符,a-f,A-F。这段代码应该会引发错误。 –