The error "HMAC Mismatch" appears when I decrypt audio, sometimes it happens, not each time.

[tanyanghzsd]

Hi,
I got a problem when I decrypted my encrypted audio file, after called '[decryptor isFinished]', the problem would appear. The error is "HMAC Mismatch", but I have no idea to solve it.

`- (void)encryptionDidFinish {
if (self.encryptor.error) {
//---> code often comes here!!! I can't get correct audio file. <---\
self.encryptedData = nil;
self.encryptor = nil;
}
else {
// self.encryptedData is complete. Use it as you like
[self writeEncryptedData];
if ([self.delegate respondsToSelector:@selector(onEncryptionDidFinish)]) {
[self.delegate onEncryptionDidFinish];
}
self.encryptedData = nil;
self.encryptor = nil;
}

}`