public static String calculateContentKeyChecksum(String uuid, byte[] aesKey) throws Exception {
Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
SecretKeySpec secretKeySpec = new SecretKeySpec(aesKey, "AES");
cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
byte[] encryptionResult = cipher.doFinal(uuid.getBytes("UTF8"));
byte[] checksumByteArray = new byte[8];
System.arraycopy(encryptionResult, 0, checksumByteArray, 0, 8);
String checksum = Base64.encode(checksumByteArray);
return checksum;
}
public static byte[] encryptSymmetricKey(String protectionKey, byte[] inputData)
throws Exception {
Cipher cipher = Cipher.getInstance("RSA/ECB/OAEPWithSHA-1AndMGF1Padding");
CertificateFactory certificateFactory = CertificateFactory.getInstance("X.509");
byte[] protectionKeyBytes = Base64.decode(protectionKey);
ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(protectionKeyBytes);
Certificate certificate = certificateFactory.generateCertificate(byteArrayInputStream);
Key publicKey = certificate.getPublicKey();
SecureRandom secureRandom = new SecureRandom();
cipher.init(Cipher.ENCRYPT_MODE, publicKey, secureRandom);
byte[] cipherText = cipher.doFinal(inputData);
return cipherText;
}