blob: 7cce72c1b88eec75384959ebcae4d73287f77bb0 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
|
File Format
===========
Header
2 bytes header version (big endian uint16, currently 2)
16 bytes file id
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 explicitly enabled with `-init -aessiv`)
16 bytes nonce
16 bytes SIV
1-4096 bytes encrypted data
Data block, XChaCha20-Poly1305 (enabled via `-init -xchacha`)
24 bytes nonce
1-4096 bytes encrypted data
16 bytes Poly1305 tag
Full block overhead (AES-GCM and AES-SIV mode) = 32/4096 = 1/128 = 0.78125 %
Full block overhead (XChaCha20-Poly1305 mode) = 40/4096 = \~1 %
Example: 1-byte file, AES-GCM and AES-SIV mode
----------------------------------------------
Header 18 bytes
Data block 33 bytes
Total: 51 bytes
Example: 5000-byte file, , AES-GCM and AES-SIV mode
---------------------------------------------------
Header 18 bytes
Data block 4128 bytes
Data block 936 bytes
Total: 5082 bytes
Example: 1-byte file, XChaCha20-Poly1305 mode
----------------------------------------------
Header 18 bytes
Data block 41 bytes
Total: 59 bytes
Example: 5000-byte file, XChaCha20-Poly1305 mode
----------------------------------------------
Header 18 bytes
Data block 4136 bytes
Data block 944 bytes
Total: 5098 bytes
|
