Compatibility of 1.9.2 with 1.4.2

[vincepii]

I have come across an encfs archive from an old backup.

The folder is from 2009 and it was encrypted with encfs 1.4.2.

I can't manage to mount it with encfs 1.9.2:

$ encfs -f -v ~/backup_dvds/20090615/Documenti/.Private_encfs ~/a                                                                                                                          [15:27:49]
2020-02-28 15:28:00,012 VER Root directory: /home/vince/backup_dvds/20090615/Documenti/.Private_encfs/ [main.cpp:540]
2020-02-28 15:28:00,012 VER Fuse arguments: (fg) (threaded) (keyCheck) encfs /home/vince/a/ -f -o use_ino -o default_permissions  [main.cpp:541]
2020-02-28 15:28:00,013 VER Boost <= 1.41 compatibility mode [FileUtils.cpp:305]
2020-02-28 15:28:00,013 VER subVersion = 20080813 [FileUtils.cpp:308]
2020-02-28 15:28:00,013 VER checking if ssl/aes(3:0:2) implements ssl/aes(2:1) [Interface.cpp:110]
2020-02-28 15:28:00,013 VER allocated cipher ssl/aes, keySize 32, ivlength 16 [SSL_Cipher.cpp:333]
2020-02-28 15:28:00,013 VER useStdin: 0 [FileUtils.cpp:1588]
EncFS Password: 
2020-02-28 15:28:02,785 VER checking if ssl/aes(3:0:2) implements ssl/aes(2:1) [Interface.cpp:110]
2020-02-28 15:28:02,785 VER allocated cipher ssl/aes, keySize 32, ivlength 16 [SSL_Cipher.cpp:333]
2020-02-28 15:28:02,785 VER cipher key size = 52 [FileUtils.cpp:1596]
2020-02-28 15:28:02,785 VER checksum mismatch: expected 1707907438, got 795786998 [SSL_Cipher.cpp:541]
2020-02-28 15:28:02,785 VER on decode of 48 bytes [SSL_Cipher.cpp:543]
Error decoding volume key, password incorrect

I am quite sure that I remember the password (I would say there's a 5% chance that I actually didn't try the correct one).

However, is 1.9.2 supposed to work with something that was encrypted with 1.4.2?

In particular, I see that crypto functions in 1.9.2 use the salt, but they weren't in 1.4.2 (accordingly, I don't have a salt in my configuration).

<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
<!DOCTYPE boost_serialization>
<boost_serialization signature="serialization::archive" version="4">
<config class_id="0" tracking_level="1" version="20080813" object_id="_0">
        <creator>EncFS 1.4.2</creator>
        <cipherAlg class_id="1" tracking_level="0" version="0">
                <name>ssl/aes</name>
                <major>2</major>
                <minor>1</minor>
        </cipherAlg>
        <nameAlg>
                <name>nameio/block</name>
                <major>3</major>
                <minor>0</minor>
        </nameAlg>
        <keySize>256</keySize>
        <blockSize>1024</blockSize>
        <uniqueIV>1</uniqueIV>
        <chainedNameIV>1</chainedNameIV>
        <externalIVChaining>1</externalIVChaining>
        <blockMACBytes>8</blockMACBytes>
        <blockMACRandBytes>0</blockMACRandBytes>
        <allowHoles>0</allowHoles>
        <encodedKeySize>52</encodedKeySize>
        <encodedKeyData>
[omitted]
        </encodedKeyData>
</config>
</boost_serialization>

[benrubson]

It should.
However you may want to give 1.4.2 a try, source code is still available :
https://github.com/vgough/encfs/releases/tag/v1.4.2

[vincepii]

I compiled 1.4.2 (this required quite a lot of patching), however, it seems that it was using .encfs5 as control file.

It seems like .encfs5 was not in .xml format.

Why does my .encfs6.xml file mentions version 1.4.2, if 1.4.2 didn't actually deal with this version of control file? Should I use a version after 1.4.2, that still didn't use the salt?

[benrubson]

Configuration file format has changed to XML yes, your could have then been updated (don't remember exactly what triggers this, would have to go through the code).

Do this test ?
Create a new FS with 1.4.2.
Unmount it.
Try to open it with 1.9.2.

Could help you to understand where your issue comes from.

[vincepii]

1.9.2 fails to load the .encfs5 configuration created by 1.4.2.

$ encfs -f -v /home/vince/encfstest/contentdir /home/vince/encfstest/encfsmount                                                                                                                                                                                                                                                                                                                       [11:40:29]
2020-02-29 11:40:37,162 VER Root directory: /home/vince/encfstest/contentdir/ [main.cpp:540]
2020-02-29 11:40:37,162 VER Fuse arguments: (fg) (threaded) (keyCheck) encfs /home/vince/encfstest/encfsmount/ -f -o use_ino -o default_permissions  [main.cpp:541]
2020-02-29 11:40:37,164 WARN  Config subversion 20080411 found, which is newer than supported version 20040813 [FileUtils.cpp:366]
2020-02-29 11:40:37,164 ERROR Found config file /home/vince/encfstest/contentdir/.encfs5, but failed to load - exiting [FileUtils.cpp:220]

I assume that at some point I used a version that migrated from .encfs5 to .encfs6.xml.

I will try to compile 1.5.0, which was using .encfs6.xml already.

[vincepii]

I tried 1.5.0.

I assume that, at some point, I had been using this version, since I was actively using the archive until Feb. 2009, on Ubuntu.

I think we can conclude that I am not remembering the password.

Thanks for your support, @benrubson !