zenon/ds-assignment-2
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Correct client challenge encoding

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First, encode the individual parameters, then add them to the command,
do the encryption and then encode the binary string again for sending.
This commit is contained in:
Tobias Eidelpes 2020-12-29 10:33:26 +01:00
parent 6666494009
commit d1bf65698d
1 changed files with 14 additions and 12 deletions
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26
src/main/java/dslab/client/MessageClient.java
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@ -174,26 +174,28 @@ public class MessageClient implements IMessageClient, Runnable {
IvParameterSpec iv = generateIv();
// Save AES cipher for subsequent communication
setAesCipher(secretKeySpec, iv);
// Concatenate challenge, secretKey and IV
byte[] concatenated = new byte[80];
System.arraycopy(clearTextChallenge, 0, concatenated, 0, 32);
System.arraycopy(secretKeySpec.getEncoded(), 0, concatenated, 32, 32);
System.arraycopy(iv.getIV(), 0, concatenated, 64, 16);
String base64Encoded = Base64.getEncoder().encodeToString(concatenated);
// Encrypt "ok <base64Encoded>"
Cipher cipher = null;
// Encode parameters to base64
String clearTextChallengeEncoded = Base64.getEncoder().encodeToString(clearTextChallenge);
String secretKeyEncoded = Base64.getEncoder().encodeToString(secretKeySpec.getEncoded());
String ivEncoded = Base64.getEncoder().encodeToString(iv.getIV());
// Concatenate command and parameters (challenge, secretKey and IV)
String concatenated = "ok" + clearTextChallengeEncoded + secretKeyEncoded + ivEncoded;
// Encrypt "<base64Encoded>"
Cipher cipher;
byte[] cipherTextChallenge;
try {
cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
cipher.init(Cipher.ENCRYPT_MODE, serverPublicKey);
cipher.update(("ok " + base64Encoded).getBytes(StandardCharsets.UTF_8));
byte[] cipherTextChallenge = cipher.doFinal();
return (new String(cipherTextChallenge, StandardCharsets.UTF_8));
cipher.update((concatenated).getBytes(StandardCharsets.UTF_8));
cipherTextChallenge = cipher.doFinal();
} catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException | IllegalBlockSizeException | BadPaddingException e) {
logger.severe("This should not be happening!");
e.printStackTrace();
shutdown();
return null;
}
return null;
// Return base64 encoded cipherMessage
return (Base64.getEncoder().encodeToString(cipherTextChallenge));
}
@Override