Add current version of libSRTP from CVS.

libsrtp/README

Index: libsrtp/README
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+Secure RTP (SRTP) Reference Implementation
+David A. McGrew
+Cisco Systems, Inc.
+mcgrew@cisco.com
+
+
+This package provides an implementation of the Secure Real-time
+Transport Protocol (SRTP), the Universal Security Transform (UST), and
+a supporting cryptographic kernel.  These mechanisms are documented in
+the Internet Drafts in the doc/ subdirectory.  The SRTP API is
+documented in include/srtp.h, and the library is in libsrtp.a (after
+compilation).  An overview and reference manual is available in
+doc/libsrtp.pdf.  The PDF documentation is more up to date than this
+file.
+
+
+Installation:
+
+./configure [ options ]       # GNU autoconf script 
+make                          # or gmake if needed; use GNU make
+
+The configure script accepts the following options:
+
+   --help              provides a usage summary
+   --disable-debug     compile without the runtime debugging system
+   --enable-syslog     use syslog for error reporting
+   --disable-stdout    use stdout for error reporting
+   --enable-console    use /dev/console for error reporting
+   --gdoi              use GDOI key management (disabled at present)
+
+By default, debbuging is enabled and stdout is used for debugging.
+You can use the above configure options to have the debugging output
+sent to syslog or the system console.  Alternatively, you can define
+ERR_REPORTING_FILE in include/conf.h to be any other file that can be
+opened by libSRTP, and debug messages will be sent to it.  
+
+This package has been tested on Mac OS X (powerpc-apple-darwin1.4),
+Cygwin (i686-pc-cygwin), and Sparc (sparc-sun-solaris2.6).  Previous
+versions have been tested on Linux and OpenBSD on both x86 and sparc
+platforms.
+
+A quick tour of this package:
+
+Makefile		targets: all, clean, ...
+README			this file
+CHANGES                 change log 
+VERSION			version number of this package
+LICENSE                 legal details (it's a BSD-like license)
+crypto/ciphers/		ciphers (null, aes_icm, ...)
+crypto/math/		crypto math routines
+crypto/hash/            crypto hashing (hmac, tmmhv2, ...)
+crypto/replay/		replay protection
+doc/			documentation: rfcs, apis, and suchlike
+include/		include files for all code in distribution
+srtp/			secure real-time transport protocol implementation
+tables/                 apps for generating tables (useful in porting)
+test/			test drivers 
+
+
+Applications
+
+  Several test drivers and a simple and portable srtp application
+  are included in the test/ subdirectory.
+
+  test driver	function tested	
+  -------------------------------------------------------------
+  kernel_driver crypto kernel (ciphers, auth funcs, rng)
+  srtp_driver	srtp in-memory tests (does not use the network)
+  rdbx_driver	rdbx (extended replay database)
+  roc_driver	extended sequence number functions 
+  replay_driver	replay database (n.b. not used in libsrtp)
+  cipher_driver	ciphers 
+  auth_driver	hash functions 
+
+  The app rtpw is a simple rtp application which reads words from
+  /usr/dict/words and then sends them out one at a time using [s]rtp.
+  Manual srtp keying uses the -k option; automated key management
+  using gdoi will be added later.
+
+usage: rtpw [-d <debug>]* [-k <key> [-a][-e]] [-s | -r] dest_ip dest_port
+or     rtpw -l
+
+  Either the -s (sender) or -r (receiver) option must be chosen.
+
+  The values dest_ip, dest_port are the ip address and udp port to
+  which the dictionary will be sent, respectively.  
+
+  options:
+
+  -s		(s)rtp sender - causes app to send words
+
+  -r		(s)rtp receive - causes app to receve words
+
+  -k <key>      use srtp master key <key>, where the
+		key is a hexadecimal value (without the
+                leading "0x")
+
+  -e            encrypt/decrypt (for data confidentiality)
+                (requires use of -k option as well)
+
+  -a            message authentication 
+                (requires use of -k option as well)
+
+  -l            list debug modules
+
+  -d <debug>    turn on debugging for module <debug>
+
+
+In order to get random 30-byte values for use as key/salt pairs , you
+can use the following bash function to format the output of
+/dev/random (where that device is available).
+
+function randhex() {
+   cat /dev/random | od --read-bytes=32 --width=32 -x | awk '{ print $2 $3 $4 $5 $6 $7 $8 $9 $10 $11 $12 $13 $14 $15 $16 }'
+}
+
+
+An example of an SRTP session using two rtpw programs follows:
+
+set k=c1eec3717da76195bb878578790af71c4ee9f859e197a414a78d5abc7451
+
+[sh1]$ test/rtpw -s -k $k -ea 0.0.0.0 9999 
+Security services: confidentiality message authentication
+set master key/salt to C1EEC3717DA76195BB878578790AF71C/4EE9F859E197A414A78D5ABC7451
+setting SSRC to 2078917053
+sending word: A
+sending word: a
+sending word: aa
+sending word: aal
+...
+
+[sh2]$ test/rtpw -r -k $k -ea 0.0.0.0 9999 
+security services: confidentiality message authentication
+set master key/salt to C1EEC3717DA76195BB878578790AF71C/4EE9F859E197A414A78D5ABC7451
+19 octets received from SSRC 2078917053 word: A
+19 octets received from SSRC 2078917053 word: a
+20 octets received from SSRC 2078917053 word: aa
+21 octets received from SSRC 2078917053 word: aal
+...
+
+Implementation Notes
+
+  * The srtp_protect() function assumes that the buffer holding the
+    rtp packet has enough storage allocated that the authentication 
+    tag can be written to the end of that packet.  If this assumption
+    is not valid, memory corruption will ensue.  
+
+  * Automated tests for the crypto functions are provided through
+    the cipher_type_self_test() and auth_type_self_test() functions.
+    These functions should be used to test each port of this code 
+    to a new platform.
+
+  * Replay protection is contained in the crypto engine, and
+    tests for it are provided.
+
+  * This implementation provides calls to initialize, protect, and
+    unprotect RTP packets, and makes as few as possible assumptions
+    about how these functions will be called.  For example, the
+    caller is not expected to provide packets in order (though if
+    they're called more than 65k out of sequence, synchronization
+    will be lost).
+    
+  * The sequence number in the rtp packet is used as the low 16 bits
+    of the sender's local packet index. Note that RTP will start its
+    sequence number in a random place, and the SRTP layer just jumps
+    forward to that number at its first invocation.  An earlier
+    version of this library used initial sequence numbers that are
+    less than 32,768; this trick is no longer required as the
+    rdbx_estimate_index(...) function has been made smarter.
+
+  * The replay window is 128 bits in length, and is hard-coded to this
+    value for now.  
+
+