### para_write ###
A modular audio stream writer. It supports a simple file writer
-output plug-in and optional WAV/raw players for ALSA (Linux) and for
-coreaudio (Mac OS). para_write can also be used as a stand-alone WAV
-or raw audio player.
+output plug-in and optional WAV/raw players for ALSA (Linux) and OSS.
+para_write can also be used as a stand-alone WAV or raw audio player.
### para_play ###
key-bindings for the most common server commands and new key-bindings
can be added easily.
-### para_fade ###
+### para_mixer ###
An alarm clock and volume-fader for OSS and ALSA.
------------
### For the impatient ###
+ git clone git://git.tuebingen.mpg.de/lopsub
+ cd lopsub && make && sudo make install
git clone git://git.tuebingen.mpg.de/osl
cd osl && make && sudo make install && sudo ldconfig
- sudo apt-get install autoconf libssl-dev help2man gengetopt m4 \
+ sudo apt-get install autoconf libssl-dev m4 \
libmad0-dev libid3tag0-dev libasound2-dev libvorbis-dev \
libfaad-dev libspeex-dev libFLAC-dev libsamplerate-dev realpath \
libasound2-dev libao-dev libreadline-dev libncurses-dev \
git clone git://git.tuebingen.mpg.de/osl
+- [lopsub](http://people.tuebingen.mpg.de/maan/lopsub/). The long
+option parser for subcommands generates the command line and config
+file parsers for all paraslash executables. Clone the source code
+repository with
+
+ git clone git://git.tuebingen.mpg.de/lopsub
+
- [gcc](ftp://ftp.gnu.org/pub/gnu/gcc) or
[clang](http://clang.llvm.org). All gcc versions >= 4.2 are currently
supported. Clang version 1.1 or newer should work as well.
during compilation require the _Bourne again shell_. It is most
likely already installed.
-- [gengetopt](ftp://ftp.gnu.org/pub/gnu/gengetopt/) is needed to
-generate the C code for the command line parsers of all paraslash
-executables.
-
-- [help2man](ftp://ftp.gnu.org/pub/gnu/help2man) is used to create
-the man pages.
-
- [m4](ftp://ftp.gnu.org/pub/gnu/m4/). Some source files are generated
from templates by the m4 macro processor.
para_server uses a challenge-response mechanism to authenticate
requests from incoming connections, similar to ssh's public key
authentication method. Authenticated connections are encrypted using
-a stream cipher, either RC4 or AES in integer counter mode.
+the AES stream cipher in integer counter mode.
-In this chapter we briefly describe RSA, RC4 and AES, and sketch the
+In this chapter we briefly describe RSA and AES, and sketch the
[authentication handshake](#Client-server.authentication)
between para_client and para_server. User management is discussed
in the section on [the user_list file](#The.user_list.file).
server. Connecting para_audiod is a different matter and is described
in a [separate section](#Connecting.para_audiod).
-RSA, RC4, AES
--------------
+RSA and AES
+-----------
-RSA is an asymmetric block cipher which is used in many applications,
-including ssh and gpg. An RSA key consists in fact of two keys,
+A block cipher is a transformation which operates on fixed-length
+blocks. For symmetric block ciphers the transformation is determined
+by a single key for both encryption and decryption. For asymmetric
+block ciphers, on the other hand, the key consists of two parts,
called the public key and the private key. A message can be encrypted
-with either key and only the counterpart of that key can decrypt
-the message. While RSA can be used for both signing and encrypting
-a message, paraslash uses RSA only for the latter purpose. The
-RSA public key encryption and signatures algorithms are defined in
-detail in RFC 2437.
-
-RC4 is a stream cipher, i.e. the input is XORed with a pseudo-random
-key stream to produce the output. Decryption uses the same function
-calls as encryption. While RC4 supports variable key lengths,
-paraslash uses a fixed length of 256 bits, which is considered a
-strong encryption by today's standards. Since the same key must never
-be used twice, a different, randomly-generated key is used for every
-new connection.
+with either key and only the counterpart of that key can decrypt the
+message. Asymmetric block ciphers can be used for both signing and
+encrypting a message.
+
+RSA is an asymmetric block cipher which is used in many applications,
+including ssh and gpg. The RSA public key encryption and signatures
+algorithms are defined in detail in RFC 2437. Paraslash relies on
+RSA for authentication.
+
+Stream ciphers XOR the input with a pseudo-random key stream to produce
+the output. Decryption uses the same function calls as encryption.
+Any block cipher can be turned into a stream cipher by generating the
+pseudo-random key stream by encrypting successive values of a counter
+(counter mode).
AES, the advanced encryption standard, is a well-known symmetric block
-cipher, i.e. a transformation operating on fixed-length blocks which
-is determined by a single key for both encryption and decryption. Any
-block cipher can be turned into a stream cipher by generating
-a pseudo-random key stream by encrypting successive values of a
-counter. The AES_CTR128 stream cipher used in paraslash is obtained
-in this way from the AES block cipher with a 128 bit block size.
+cipher. Paraslash employs AES in counter mode as described above to
+encrypt communications. Since a stream cipher key must not be used
+twice, a random key is generated for every new connection.
Client-server authentication
----------------------------
the session key known to both peers.
paraslash relies on the quality of the pseudo-random bytes provided
-by the crypto library (openssl or libgcrypt), on the security of the
-implementation of the RSA, RC4 and AES crypto routines and on the
+by the crypto library (openssl or libgcrypt), on the security of
+the implementation of the RSA and AES crypto routines and on the
infeasibility to invert the SHA1 function.
Neither para_server or para_client create RSA keys on their
para_client help
-contains in the third column the permissions needed to execute the
-command.
+contains the permissions needed to execute the command.
It is possible to make para_server reread the user_list file by
executing the paraslash "hup" command or by sending SIGHUP to the
also limited. For example only one application can open the device
at any time. The OSS writer is activated by default on BSD Systems.
-- *OSX*. Mac OS X has yet another API called CoreAudio. The OSX writer
-for this API is only compiled in on such systems and is of course
-the default there.
-
- *FILE*. The file writer allows to capture the audio stream and
write the PCM data to a file on the file system rather than playing
it through a sound device. It is supported on all platforms and is
projects / paraslash.git / blobdiff