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mutable.txt: need offset of EOF too

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This commit is contained in:
Brian Warner 2007-11-02 22:28:07 -07:00
parent 49cc32d012
commit 70bd92f24d
1 changed files with 18 additions and 13 deletions
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31
docs/mutable.txt
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@ -370,6 +370,10 @@ steps will be implemented in a separate class in allmydata/mutable.py .
This SMDF data lives inside a server-side MutableSlot container. The server
is oblivious to this format.
This data is tightly packed. In particular, the share data is defined to run
all the way to the beginning of the encrypted private key (the encprivkey
offset is used both to terminate the share data and to begin the encprivkey).
# offset size name
1 0 1 version byte, \x00 for this format
2 1 8 sequence number. 2^64-1 must be handled specially, TBD
@ -378,25 +382,26 @@ is oblivious to this format.
41 1 k
42 1 N
43 8 segment size
51 8 data length
5 59 32 offset table:
91 4 (7) signature
95 4 (8) share hash chain
99 4 (9) block hash tree
103 4 (10) IV
107 4 (11) share data
111 8 (12) encrypted private key
TODO: (13) end of file
6 119 256 verification key (2048 RSA key 'n' value, e=3)
7 375 256 signature= RSAenc(sig-key, H(version+seqnum+r+encparm))
8 631 (a) share hash chain, encoded as:
51 8 data length (of original plaintext)
5 59 36 offset table:
59 4 (7) signature
63 4 (8) share hash chain
67 4 (9) block hash tree
71 4 (10) IV
75 4 (11) share data
79 8 (12) encrypted private key
87 8 (13) EOF
6 95 256 verification key (2048 RSA key 'n' value, e=3)
7 361 256 signature= RSAenc(sig-key, H(version+seqnum+r+encparm))
8 607 (a) share hash chain, encoded as:
"".join([pack(">H32s", shnum, hash)
for (shnum,hash) in needed_hashes])
9 ?? (b) block hash tree, encoded as:
"".join([pack(">32s",hash) for hash in block_hash_tree])
10 ?? 16 IV (share data is AES(H(readkey+IV)) )
11 ?? LEN share data
11 ?? LEN share data (no gap between this and encprivkey)
12 ?? 256 encrypted private key= AESenc(write-key, RSA 'd' value)
13 ?? -- EOF
(a) The share hash chain contains ceil(log(N)) hashes, each 32 bytes long.
This is the set of hashes necessary to validate this share's leaf in the