removed legacy SIV_CTRMAC note

Author: tobihagemann

source/security/vault.rst

@@ -6,10 +6,6 @@ Vault Cryptography
 File Header Encryption
 ----------------------
 
-.. note::
-
-    The following section only applies to vaults with the cipher combo ``SIV_GCM`` in the decoded JWT payload. For vaults with ``SIV_CTRMAC``, have a look at our `1.6 documentation <https://docs.cryptomator.org/en/1.6/security/architecture/#file-header-encryption>`_.
-
 The file header stores certain metadata, which is needed for file content encryption.
 It consists of 68 bytes.