diff options
| -rw-r--r-- | Documentation/SECURITY.md | 11 | ||||
| -rw-r--r-- | Documentation/file-name-encryption.svg | 14 | ||||
| -rw-r--r-- | Documentation/performance.txt | 7 | ||||
| -rw-r--r-- | README.md | 17 |
4 files changed, 32 insertions, 17 deletions
diff --git a/Documentation/SECURITY.md b/Documentation/SECURITY.md index 003eadb..dff2fab 100644 --- a/Documentation/SECURITY.md +++ b/Documentation/SECURITY.md @@ -15,7 +15,7 @@ The KEK is generated from the user password using `scrypt`. File Contents ------------- -All file contents are encrypted using AES-256-GCM. +All file contents are encrypted using AES-256-GCM (Galois/Counter Mode). Files are segmented into 4KB blocks. Each block gets a fresh random 96 bit IV each time it is modified. A 128-bit authentication tag (GHASH) @@ -37,8 +37,11 @@ File Names Every directory gets a 128-bit directory IV that is stored in each directory as `gocryptfs.diriv`. -File names are encrypted using AES-256-CBC with the directory IV as -initialization vector. The Base64 encoding limits the usable filename length -to 176 characters. +File names are encrypted using AES-256-EME (ECB-Mix-ECB wide-block encryption, +see https://github.com/rfjakob/eme for details) with the directory IV +as initialization vector. EME fixes the prefix leak that occours with CBC +encryption.  + +The Base64 encoding limits the usable filename length to 176 characters. diff --git a/Documentation/file-name-encryption.svg b/Documentation/file-name-encryption.svg index 4093f24..45222e2 100644 --- a/Documentation/file-name-encryption.svg +++ b/Documentation/file-name-encryption.svg @@ -149,9 +149,9 @@ borderopacity="1.0" inkscape:pageopacity="0.0" inkscape:pageshadow="2" - inkscape:zoom="1.979899" - inkscape:cx="299.54034" - inkscape:cy="65.144047" + inkscape:zoom="2.8" + inkscape:cx="290.22759" + inkscape:cy="52.741737" inkscape:document-units="px" inkscape:current-layer="layer1" showgrid="true" @@ -186,7 +186,7 @@ <dc:format>image/svg+xml</dc:format> <dc:type rdf:resource="http://purl.org/dc/dcmitype/StillImage" /> - <dc:title></dc:title> + <dc:title /> </cc:Work> </rdf:RDF> </metadata> @@ -267,7 +267,7 @@ id="tspan4157-3-0-7-6-8" x="316.79153" y="309.39807" - style="font-style:normal;font-variant:normal;font-weight:normal;font-stretch:normal;font-size:15.00342369px;font-family:sans-serif;-inkscape-font-specification:sans-serif;letter-spacing:0px">AES-256-CBC</tspan></text> + style="font-style:normal;font-variant:normal;font-weight:normal;font-stretch:normal;font-size:15.00342369px;font-family:sans-serif;-inkscape-font-specification:sans-serif;letter-spacing:0px">AES-256-EME</tspan></text> <path style="opacity:1;fill:none;fill-opacity:1;stroke:#000000;stroke-width:1;stroke-miterlimit:4;stroke-dasharray:none;stroke-dashoffset:0;stroke-opacity:1;marker-end:url(#marker8559)" d="m 558.97059,270.16733 -169.78791,0.0896 0,17.75633" @@ -359,14 +359,14 @@ <text xml:space="preserve" style="font-style:normal;font-variant:normal;font-weight:bold;font-stretch:normal;font-size:90.01774597px;line-height:125%;font-family:Arial;-inkscape-font-specification:'Arial Bold';letter-spacing:67.66333771px;word-spacing:0px;fill:#aa00d4;fill-opacity:1;stroke:none;stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1" - x="462.66055" + x="456.66174" y="266.66168" id="text4155-88-3-5-0" sodipodi:linespacing="125%" transform="scale(1.0001971,0.99980293)"><tspan sodipodi:role="line" id="tspan4157-9-7-3-8" - x="462.66055" + x="456.66174" y="266.66168" style="font-style:normal;font-variant:normal;font-weight:normal;font-stretch:normal;font-size:15.00295734px;font-family:sans-serif;-inkscape-font-specification:sans-serif;letter-spacing:0px;fill:#aa00d4">IV</tspan></text> <rect diff --git a/Documentation/performance.txt b/Documentation/performance.txt index 2194311..c0bd2d0 100644 --- a/Documentation/performance.txt +++ b/Documentation/performance.txt @@ -2,11 +2,12 @@ All test performed on tmpfs, /tmp/a mounted on /tmp/b. The used test archive is https://www.kernel.org/pub/linux/kernel/v3.0/linux-3.0.tar.gz . UNTAR: tar xfz ../linux-3.0.tar.gz -LS: ls -lR > /dev/null -RM: rm -rf linux-3.0 +LS: ls -lR linux-3.0 > /dev/null +RM: rm -Rf linux-3.0 VERSION UNTAR LS RM v0.4 48 1.5 5 v0.5-rc1 56 7 19 v0.5-rc1-1 54 4.1 9 -v0.5-rc1-2 45 1.7 3.4 +v0.5-rc1-2 45 1.7 3.4 +v0.6 47 1.8 4.3 @@ -6,10 +6,10 @@ gocryptfs is built on top the excellent [go-fuse](https://github.com/hanwen/go-fuse) FUSE library and its LoopbackFileSystem API. -This project was inspired by [EncFS](https://github.com/vgough/encfs) -and strives to fix its security issues (see EncFS tickets 9, 13, 14, 16). +This project was inspired by EncFS and strives to fix its security +issues while providing good performance. For details on the security of gocryptfs see the -[SECURITY.md](Documentation/SECURITY.md) document. +[SECURITY.md](Documentation/SECURITY.md) design document. Current Status -------------- @@ -97,6 +97,17 @@ The output should look like this: Changelog --------- +v0.6 +* **Wide-block filename encryption using EME + DirIV** + * EME (ECB-Mix-ECB) provides even better security than CBC as it fixes + the prefix leak. The used Go EME implementation is + https://github.com/rfjakob/eme which is, as far as I know, the first + implementation of EME in Go. + * This is a forwards-compatible change. gocryptfs v0.5 can mount filesystems + created by earlier version but not the other way round. +* New command-line option: + * `-emenames`: Enable EME filename encryption (default true) + v0.5 * **Stronger filename encryption: DirIV** * Each directory gets a random 128 bit file name IV on creation, |
