Note: This page is horribly out of
date.
You can find the current pages for the dm-crypt
project (the Linux kernel part) here:
https://gitlab.com/cryptsetup/cryptsetup/wikis/DMCrypt
and the project page for the command line tool
cryptsetup (with Linux Unified Key
Setup - LUKS) here: https://gitlab.com/cryptsetup/cryptsetup.
Old page:
Device-mapper is a new infrastructure in the Linux 2.6 kernel that provides
a generic way to create virtual layers of block devices that can do different
things on top of real block devices like striping, concatenation, mirroring,
snapshotting, etc... The device-mapper is used by the
LVM2 and
EVMS 2.x tools.
dm-crypt is such a device-mapper target that provides transparent encryption of
block devices using the new Linux 2.6 cryptoapi. The user can basically specify
one of the symmetric ciphers, a key (of any allowed size), an iv generation mode
and then the user can create a new block device in /dev. Writes to this device
will be encrypted and reads decrypted. You can mount your filesystem on it as usual.
But without the key you can't access your data.
It does basically the same as cryptoloop only that it's a much cleaner code and
better suits the need of a block device and has a more flexible configuration
interface. The on-disk format is also compatible. In the future you will be able
to specify other iv generation modes for enhanced security (you'll have to
reencrypt your filesystem though).
I've set up a Wiki.
There's a mailing list at .
If you want to subscribe, use the mailman
web interface or its
archive.
Gmane provides a NNTP interface and also a
web archive
for this mailing list.
There is support for dm-crypt in the latest official kernel
2.6.4
which you can find on kernel.org.
Please use the mirrors for downloads.
There is a HIGHMEM cryptoapi bug in kernels before 2.6.4-rc2, please
upgrade if you were using such a kernel.
The latest version of the native userspace setup tool is cryptsetup 0.1.
Clemens Fruhwirth is maintaining an
enhanced
version of cryptsetup with the LUKS extension that allows you to have an
on-disk block of metadata which is superior to the current mechanism and was
my long term plan anyway but I didn't find the time to implement that yet...
In practical terms, the "6GB Patch" allows a heavily modded MUGEN 1.1 to utilize between 5.2GB and 6.4GB of combined RAM + Page file before crashing. For roster builders, this means you can run a full 10,000+ character selection screen with 4K stages and high-fidelity music without stuttering.
This is where our hero, the 4GB Patch (often misremembered as a "6GB" patch), comes into play. It’s a small but powerful utility, most famously created by , that directly alters the mugen.exe file.
If patching WinMUGEN isn't working, or if you want true modern memory support (actually using 6GB+), the community recommends switching to .
By providing a faster, smoother, and more responsive experience, the Mugen 6GB patch is an essential tool for anyone who wants to get the most out of their device. Whether you're a gamer, a busy professional, or simply someone who wants to enjoy a seamless user experience, the Mugen 6GB patch is definitely worth considering.
Memory patches do not boost CPU processing power. If your game lags, reduce the resolution settings in mugen.cfg or optimize the file sizes of your heaviest character sprites using specialized optimization tools.
Here is everything you need to know to install the patch, optimize your engine, and stop memory crashes forever. Why Does MUGEN Crash? Understanding the Memory Limit
: While it doesn't necessarily boost FPS, it prevents the stuttering caused by the engine constantly swapping data in and out of a cramped memory space.
How many are you trying to host in your screenpack? Share public link
IKEMEN GO is a popular open-source, modern engine designed to be highly compatible with MUGEN content. It handles memory much better, is written in Go, and is natively 64-bit, making it more stable for massive rosters.
For those who may be new to Mugen, let's take a brief look at what it's all about. Mugen is a popular custom ROM (Read-Only Memory) that allows users to modify and enhance their Android devices. With Mugen, users can enjoy a level of customization and control that is not possible on stock Android. Mugen is known for its stability, performance, and flexibility, making it a favorite among Android enthusiasts. The team behind Mugen works tirelessly to develop and release updates that cater to the evolving needs of users.
: It eliminates the "Out of Memory" errors during the loading screen. Performance
When a MUGEN user loads a huge screenpack, dozens of high-definition stages, or thousands of characters with large sprite sheets, the executable hits this 4GB ceiling. When it does, MUGEN fails to allocate more memory and simply crashes, often showing an "out of memory" error or just vanishing without notice. What the Patch Does
Unleashing the Multi-Verse: The Ultimate Guide to the MUGEN 4GB/6GB Large Address Aware Patch
If you have a heavy MUGEN build (e.g., 500+ slots, HD stages) and it won't open, follow these instructions:
By allowing the engine to hold more data in RAM, it reduces the need to constantly load assets from the hard drive, which can cause stuttering. How to Apply the MUGEN 6GB Patch
The on-disk layouts used by the current 2.6 cryptoloop are supported by dm-crypt.
Cryptoloop also uses cryptoapi so the name of the ciphers are the same. Cryptoloop also
supports ECB and CBC mode. Use <cipher>-ecb and
<cipher>-plain accordingly with dm-crypt. If you didn't
explicitly specify either -ecb or -cbc before you don't need it now, the default plain
IV generation will be used. There will be additional (incompatible, but more secure) possibilites
in the future because the unhashed sector number as IV is too predictible.
You'll need to figure out how your passphrase was turned into a key to use for losetup.
There are several patches floating around doing things differently. But usually cryptsetup
will provide a working solution to recreate the same key from your passphrase.
If you want to migrate from 2.4 cryptoloop please take a look at Clemens Fruhwirth's
Cryptoloop
Migration Guide. He describes the differences between 2.4 and 2.6 cryptoapi (or basically
the bugs in 2.4 cryptoapi...). If you need to cut the key size you can use the -s
option instead of playing with dd.
(BTW: Clemens has a i586 optimized version of the aes and serpent cipher on his page,
about twice as fast as the kernel implementation.)
Why dm-crypt?
Originally it started as a fun project because I wanted to play with the new Linux 2.6 internals.
I got a lot of great help from the device-mapper guys at Sistina (now Redhat). Thank you very
much!
It turned out that this implementation worked great and is very clean compared to the hacked
loop device. The device-mapper core provides much better facilities to stack block devices.
dm-crypt uses mempools to assure we never run into out-of-memory deadlocks when allocating
buffers.
Also the device-mapper configuration interface provides much more flexibility than the losetup
ioctl. And you can create as many devices as you want with any names you want and combine them
with other dm targets. Online device resizing is also possible, e.g. if you use dm-crypt on top
of a logical volume. There might perhaps even be LVM or EVMS support for device encryption
in the future.
In practical terms, the "6GB Patch" allows a heavily modded MUGEN 1.1 to utilize between 5.2GB and 6.4GB of combined RAM + Page file before crashing. For roster builders, this means you can run a full 10,000+ character selection screen with 4K stages and high-fidelity music without stuttering.
This is where our hero, the 4GB Patch (often misremembered as a "6GB" patch), comes into play. It’s a small but powerful utility, most famously created by , that directly alters the mugen.exe file.
If patching WinMUGEN isn't working, or if you want true modern memory support (actually using 6GB+), the community recommends switching to .
By providing a faster, smoother, and more responsive experience, the Mugen 6GB patch is an essential tool for anyone who wants to get the most out of their device. Whether you're a gamer, a busy professional, or simply someone who wants to enjoy a seamless user experience, the Mugen 6GB patch is definitely worth considering. mugen+6gb+patch
Memory patches do not boost CPU processing power. If your game lags, reduce the resolution settings in mugen.cfg or optimize the file sizes of your heaviest character sprites using specialized optimization tools.
Here is everything you need to know to install the patch, optimize your engine, and stop memory crashes forever. Why Does MUGEN Crash? Understanding the Memory Limit
: While it doesn't necessarily boost FPS, it prevents the stuttering caused by the engine constantly swapping data in and out of a cramped memory space. In practical terms, the "6GB Patch" allows a
How many are you trying to host in your screenpack? Share public link
IKEMEN GO is a popular open-source, modern engine designed to be highly compatible with MUGEN content. It handles memory much better, is written in Go, and is natively 64-bit, making it more stable for massive rosters.
For those who may be new to Mugen, let's take a brief look at what it's all about. Mugen is a popular custom ROM (Read-Only Memory) that allows users to modify and enhance their Android devices. With Mugen, users can enjoy a level of customization and control that is not possible on stock Android. Mugen is known for its stability, performance, and flexibility, making it a favorite among Android enthusiasts. The team behind Mugen works tirelessly to develop and release updates that cater to the evolving needs of users. It’s a small but powerful utility, most famously
: It eliminates the "Out of Memory" errors during the loading screen. Performance
When a MUGEN user loads a huge screenpack, dozens of high-definition stages, or thousands of characters with large sprite sheets, the executable hits this 4GB ceiling. When it does, MUGEN fails to allocate more memory and simply crashes, often showing an "out of memory" error or just vanishing without notice. What the Patch Does
Unleashing the Multi-Verse: The Ultimate Guide to the MUGEN 4GB/6GB Large Address Aware Patch
If you have a heavy MUGEN build (e.g., 500+ slots, HD stages) and it won't open, follow these instructions:
By allowing the engine to hold more data in RAM, it reduces the need to constantly load assets from the hard drive, which can cause stuttering. How to Apply the MUGEN 6GB Patch
Please contact the mailing list: dm-crypt@saout.de. Or in case there is a problem with the mailing list, me: .