---
title: Encryption Error (Error 35)
slug: troubleshooting/encryption-error-error-35
createdAt: 2025-04-23T20:48:50.267Z
---

### ERROR

Encryption Error (Error 35) can happen in two cases:

On input:
"Double encryption" error - source is enrypted Zixi push/pull, and there is encryption configuration on the input

On output:
"No decryption key" error - input is encrypted Zixi push/pull, output expects clear data (UDP/RTP/RIST/SRT/ASI/RTMP/TCP...), and there is no decryption key defined.

Note: Mismatch in keys will not generate this error, payload will simply be corrupted.
Since the is no assumption on payload structure, a mismatch on encryption key simply shows up as corrupted data.

### RESOLUTION

In order to detect decryption key mismatch we recommend adding 3 counters on outputs:

1. Number of corrupted compressed packets (a.k.a null-packet-optimization, although the name is misleading)
2. Number of total compressed packets
3. Number of non-TS packets, post-decryption

If counters 1 or 3 increase, and there is a decryption key defined - this is a strong indication of a wrong key.
Corrupted compressed packets are a clear giveaway, especially if it happens to a high proportion of the compressed packets (counter 1 out of counter 2).
Although compression is the default - it is not always enabled. In that case, when counters 1 and 2 are not growing, counter 3 can play a role.

Counter 3 can still increase when using non-TS payload, with compression disabled, and a correct static-key decryption, although this combination is a less likely scenario than simply a mismatch in keys.