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update README.txt

This commit is contained in:
alexmullins 2015-10-27 04:25:11 -05:00
parent fa71aa0e14
commit 5ca6f99620
1 changed files with 9 additions and 6 deletions
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README.txt
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@ -28,11 +28,14 @@ generates a master key broken into the following:
5. Authentication Key is same size as AES key.
6. Authentication with HMAC-SHA1-80 (truncated to 80bits).
7. A new master key is generated for every file.
7.5. CTR IV = 01 and increases for each file. Everything I've read said
it starts at 00 so I need clarification here. See winzipkeygen for example.
8. The file header and directory header compression method will
be 99 (decimal). The actual compression method will be in the
extra's payload at the end of the directory header.
be 99 (decimal) indicating Winzip AES encryption. The actual
compression method will be in the extra's payload at the end
of the headers.
9. A extra field will be added to the file header and directory
header identified by 0x9901 and contains the following info:
header identified by the ID 0x9901 and contains the following info:
a. Header ID (2 bytes)
b. Data Size (2 bytes)
c. Vendor Version (2 bytes)
@ -40,7 +43,7 @@ header identified by 0x9901 and contains the following info:
e. AES Strength (1 byte)
f. Compression Method (2 bytes)
10. The Data Size is always 7.
11. The Vendor Version can either be 0x0001 (AE-1) or
11. The Vendor Version can be either 0x0001 (AE-1) or
0x0002 (AE-2).
12. Vendor ID is ASCII "AE"
13. AES Strength:
@ -48,7 +51,7 @@ header identified by 0x9901 and contains the following info:
b. 0x02 - AES-192
c. 0x03 - AES-256
14. Compression Method is the actual compression method
used that was replaced by the encryption process.
used that was replaced by the encryption process mentioned in #8.
15. AE-1 keeps the CRC and should be verified after decompression.
16. AE-2 removes the CRC and shouldn't be verified after decompression.
AE-2 removes the CRC and shouldn't be verified after decompression.
Refer to http://www.winzip.com/aes_info.htm#winzip11 for the reasoning.