X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=web%2Fmanual.m4;h=e809c8b22be7ddea6a6e9335550670098a303b06;hp=4edce03639b5ca4b719178e148f05a98fc3a6a21;hb=6eab6671f857009b6d6a2de2c2ec8187f869f705;hpb=017aa6503f639c7d0bb7b7be200da5fde4f2f4bd

diff --git a/web/manual.m4 b/web/manual.m4
index 4edce036..e809c8b2 100644
--- a/web/manual.m4
+++ b/web/manual.m4
@@ -112,7 +112,7 @@ can be used by any scripting language to produce user interfaces with
 little programming effort.
 
 All connections between para_server and para_client are encrypted
-with a symmetric RC4 session key. For each user of paraslash you must
+with a symmetric session key. For each user of paraslash you must
 create a public/secret RSA key pair for authentication.
 
 If para_client is started without non-option arguments, an interactive
@@ -505,9 +505,9 @@ User management
 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
-the RC4 stream cipher.
+a stream cipher, either RC4 or AES in integer counter mode.
 
-In this chapter we briefly describe RSA and RC4 and sketch the
+In this chapter we briefly describe RSA, RC4 and AES, and sketch the
 REFERENCE(Client-server authentication, authentication handshake)
 between para_client and para_server. User management is discussed
 in the section on REFERENCE(The user_list file, the user_list file).
@@ -517,8 +517,8 @@ in a REFERENCE(Connecting para_audiod, separate section).
 
 
 
-RSA and RC4
-~~~~~~~~~~~
+RSA, RC4, 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,
@@ -537,6 +537,15 @@ 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.
 
+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.
+
+
 Client-server authentication
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
@@ -557,7 +566,7 @@ as follows:
 	fixed-length buffer with random bytes, encrypts that buffer
 	using the public key and sends the encrypted buffer to the
 	client. The first part of the buffer is the challenge which
-	is used for authentication while the second part is the RC4
+	is used for authentication while the second part is the
 	session key.
 
 	- para_client receives the encrypted buffer and decrypts it
@@ -574,12 +583,12 @@ as follows:
 
 	- Otherwise the user is considered authenticated and the client
 	is allowed to proceed by sending a command to be executed. From
-	this point on the communication is encrypted using the RC4
-	stream cipher with the session key known to both peers.
+	this point on the communication is encrypted using the stream
+	cipher with 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 and RC4 crypto routines and on the
+the implementation of the RSA, RC4 and AES crypto routines and on the
 infeasibility to invert the SHA1 function.
 
 Neither para_server or para_client create RSA keys on their own. This