4
Google의 조언 here을 따르고 코드를 guide으로 사용합니다. 나는 암호화 된 hyperlocal 문자열을 사용하여 내가 작성한 암호 해독 방법을 시험해 보았습니다. (그러한 방법을 쓰는 것에 대한 저의 시도로 인해 많은 두통이 생겼습니다.Signature Mismatch (Google RTB)로 초 지역 정보를 해독
나는 적절한 무결성과 암호화 키를 제공하고있어 나는 그들이 (구글의 RTB는 초정밀 페이지를 해독 아래로 낮은) 자신의 예를 암호 해독에 제공하는 바이트 배열을 사용하고 있습니다 비록 어떤 이유로 Signature Mismatch을 얻고있다. example in the documentation가 나타납니다
package anon.bidder.adx;
import java.io.ByteArrayOutputStream;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;
import javax.crypto.Mac;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import org.apache.commons.codec.binary.Hex;
import org.apache.log4j.Logger;
public class AdxBidRequestDecryptor {
private static final int INITIALIZATION_VECTOR_SIZE = 16;
private static final int SIGNATURE_SIZE = 4;
private static final int BLOCK_SIZE = 20;
public static class DecrypterException extends Exception {
public DecrypterException(String message) {
super(message);
}
}
public static byte[] hexStringToByteArray(String s) {
int len = s.length();
byte[] data = new byte[len/2];
for (int i = 0; i < len; i += 2) {
data[i/2] = (byte) ((Character.digit(s.charAt(i), 16) << 4)
+ Character.digit(s.charAt(i+1), 16));
}
return data;
}
public static void main(String args[]){
byte[] ciphertext = hexStringToByteArray("E2014EA201246E6F6E636520736F7572636501414243C0ADF6B9B6AC17DA218FB50331EDB376701309CAAA01246E6F6E636520736F7572636501414243C09ED4ECF2DB7143A9341FDEFD125D96844E25C3C202466E6F6E636520736F7572636502414243517C16BAFADCFAB841DE3A8C617B2F20A1FB7F9EA3A3600256D68151C093C793B0116DB3D0B8BE9709304134EC9235A026844F276797");
byte[] encryptionKey = {(byte)0x02, (byte)0xEE, (byte)0xa8, (byte)0x3c, (byte)0x6c, (byte)0x12, (byte)0x11, (byte)0xe1, (byte)0x0b,
(byte) 0x9f, (byte) 0x88, (byte) 0x96, (byte) 0x6c, (byte) 0xee, (byte) 0xc3, (byte) 0x49, (byte) 0x08, (byte) 0xeb, (byte) 0x94, (byte) 0x6f, (byte) 0x7e,
(byte) 0xd6, (byte) 0xe4, (byte) 0x41, (byte) 0xaf, (byte) 0x42, (byte) 0xb3, (byte) 0xc0, (byte) 0xf3, (byte) 0x21, (byte) 0x81, (byte) 0x40};
byte[] integrityKey = {(byte) 0xbf, (byte) 0xFF, (byte) 0xec, (byte) 0x55, (byte) (byte) 0xc3, (byte) 0x01, (byte) 0x30, (byte) 0xc1, (byte) 0xd8,
(byte) 0xcd, (byte) 0x18, (byte) 0x62, (byte) 0xed, (byte) 0x2a, (byte) 0x4c, (byte) 0xd2, (byte) 0xc7, (byte) 0x6a, (byte) 0xc3, (byte) 0x3b, (byte) 0xc0,
(byte) 0xc4, (byte) 0xce, (byte) 0x8a, (byte) 0x3d, (byte) 0x3b, (byte) 0xbd, (byte) 0x3a, (byte) 0xd5, (byte) 0x68, (byte) 0x77, (byte) 0x92};
try {
byte[] plain = decrypt(ciphertext, new SecretKeySpec(encryptionKey,"HmacSHA1"),new SecretKeySpec(integrityKey,"HmacSHA1"));
} catch (DecrypterException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static byte[] decrypt(byte[] ciphertext,
SecretKey encryptionKey,
SecretKey integrityKey)
throws DecrypterException {
try {
// Step 1. find the length of initialization vector and clear text.
final int plaintext_length =
ciphertext.length - INITIALIZATION_VECTOR_SIZE - SIGNATURE_SIZE;
if (plaintext_length < 0) {
throw new RuntimeException("The plain text length can't be negative.");
}
byte[] iv = Arrays.copyOf(ciphertext, INITIALIZATION_VECTOR_SIZE);
// Step 2. recover clear text
final Mac hmacer = Mac.getInstance("HmacSHA1");
final int ciphertext_end = INITIALIZATION_VECTOR_SIZE + plaintext_length;
final byte[] plaintext = new byte[plaintext_length];
boolean add_iv_counter_byte = true;
for (int ciphertext_begin = INITIALIZATION_VECTOR_SIZE, plaintext_begin = 0;
ciphertext_begin < ciphertext_end;) {
hmacer.reset();
hmacer.init(encryptionKey);
final byte[] pad = hmacer.doFinal(iv);
int i = 0;
while (i < BLOCK_SIZE && ciphertext_begin != ciphertext_end) {
plaintext[plaintext_begin++] =
(byte)(ciphertext[ciphertext_begin++]^pad[i++]);
}
if (!add_iv_counter_byte) {
final int index = iv.length - 1;
add_iv_counter_byte = ++iv[index] == 0;
}
if (add_iv_counter_byte) {
add_iv_counter_byte = false;
iv = Arrays.copyOf(iv, iv.length + 1);
}
}
// Step 3. Compute integrity hash. The input to the HMAC is clear_text
// followed by initialization vector, which is stored in the 1st section
// or ciphertext.
hmacer.reset();
hmacer.init(integrityKey);
hmacer.update(plaintext);
hmacer.update(Arrays.copyOf(ciphertext, INITIALIZATION_VECTOR_SIZE));
final byte[] computedSignature = Arrays.copyOf(hmacer.doFinal(), SIGNATURE_SIZE);
final byte[] signature = Arrays.copyOfRange(
ciphertext, ciphertext_end, ciphertext_end + SIGNATURE_SIZE);
if (!Arrays.equals(signature, computedSignature)) {
throw new DecrypterException("Signature mismatch.");
}
return plaintext;
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException("HmacSHA1 not supported.", e);
} catch (InvalidKeyException e) {
throw new RuntimeException("Key is invalid for this purpose.", e);
}
}
}