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| author | Jakob Unterwurzacher | 2019-01-04 19:31:41 +0100 |
|---|---|---|
| committer | Jakob Unterwurzacher | 2019-01-04 19:31:41 +0100 |
| commit | 8c18fb5db9544486412c697a90ad55710639b36a (patch) | |
| tree | a128c9c1a3793365e0eadff63aea6779225c0ac5 | |
| parent | 28584d0d2c829fa1824bebc13e446968ebdee6b6 (diff) | |
file-format.md: document AES-SIV block layout
Fixes https://github.com/rfjakob/gocryptfs/issues/299
| -rw-r--r-- | Documentation/file-format.md | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/Documentation/file-format.md b/Documentation/file-format.md index ad1fb3f..5699f9e 100644 --- a/Documentation/file-format.md +++ b/Documentation/file-format.md @@ -6,12 +6,18 @@ Header 2 bytes header version (big endian uint16, currently 2) 16 bytes file id -Data block +Data block, default AES-GCM mode 16 bytes GCM IV (nonce) 1-4096 bytes encrypted data 16 bytes GHASH +Data block, AES-SIV mode (used in reverse mode, or when explicitely enabled with `-init -aessiv`) + + 16 bytes nonce + 16 bytes SIV + 1-4096 bytes encrypted data + Full block overhead = 32/4096 = 1/128 = 0.78125 % Example: 1-byte file |