diff --git a/docs/internals/data-structures.rst b/docs/internals/data-structures.rst index 51b34a0ba..8a40fb720 100644 --- a/docs/internals/data-structures.rst +++ b/docs/internals/data-structures.rst @@ -437,9 +437,9 @@ Encryption .. seealso:: The :ref:`borgcrypto` section for an in-depth review. -AES_-256 is used in CTR mode (so no need for padding). A 64bit initialization -vector is used, a `HMAC-SHA256`_ is computed on the encrypted chunk with a -random 64bit nonce and both are stored in the chunk. +AES_-256 is used in CTR mode (so no need for padding). A 64 bit initialization +vector is used, a `HMAC-SHA256`_ is computed on the encrypted chunk +and both are stored in the chunk. The header of each chunk is: ``TYPE(1)`` + ``HMAC(32)`` + ``NONCE(8)`` + ``CIPHERTEXT``. Encryption and HMAC use two different keys.