I am attempting to encrypt a pdf and then display it in the reader.
I am overriding the PDFAESStream class and attempting to input my own decryption method, but it is not working.
Code:
MessageDigest sha = MessageDigest.getInstance("SHA-1");
key = sha.digest(key);
key = Arrays.copyOf(key, 16);
SecretKeySpec skey = new SecretKeySpec(key, "AES");
byte[] ivbytes = new byte[] { 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 };
IvParameterSpec iv = new IvParameterSpec(ivbytes);//need IV in CBC mode
m_dec_cipher = Cipher.getInstance("AES/CBC/PKCS7Padding");
m_dec_cipher.init(Cipher.DECRYPT_MODE, skey, iv);
m_enc_cipher = Cipher.getInstance("AES/CBC/PKCS7Padding");
m_enc_cipher.init(Cipher.ENCRYPT_MODE, skey, iv);
This does not work and I get a -3 error when opening the stream.
I am using the Secure.getString(context().getContentResolver(),Secure.ANDROID_ID).getBytes(UTF8) method to generate the 16 byte key after encoding it to SHA-1 and pulling out the first 16 bytes.
Can this work? What is wrong with the encryption?
thanks
