.\" Copyright (C) 2004-2024 by the University of Southern California
.\"
.\" This program is free software; you can redistribute it and/or
.\" modify it under the terms of the GNU General Public License,
.\" version 2, as published by the Free Software Foundation.
.\"
.\" This program is distributed in the hope that it will be useful,
.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
.\" GNU General Public License for more details.
.\"
.\" You should have received a copy of the GNU General Public License along
.\" with this program; if not, write to the Free Software Foundation, Inc.,
.\" 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
.\"
.TH cryptopANT 3cryptopANT "2024-01-24"
.SH NAME
cryptopANT \- IP Address Anonymization Library
.SH SYNOPSIS
.nf
.ft B
#include <cryptopANT.h>
.LP
.ft B
.ft
.fi
.SH DESCRIPTION
The cryptopANT ip address anonymization library
implements techniques for IPv4 and IPv6 address anonymization first
described in:
.PP
.I
.IP "'Prefix-Preserving IP  Address Anonymization'," 
  Computer Networks, Volume 46, Issue 2, 7 October 2004, Pages 253-272, Elsevier.
.PP
commonly known as Crypto-PAn.
.PP
.PP
This implementation is provided by USC/ISI ANT project:
.B "http://ant.isi.edu"
.PP
.SS
.SS API Overview
.PP
.EX
.BR "int scramble_init_from_file(const char *keyfile, scramble_crypt_t c4, scramble_crypt_t c6, int *do_mac)"
.EE
.IP
Initializes library from a keyfile and sets up underlying cryptographical mechanism for scrambling
of IPv4 (c4) and IPv6 (c6) addresses.  See 
.BR scramble_crypt_t
for possible values of c4 and c6.  Typically used are:
.BR SCRAMBLE_NONE
for no scrambling or
.BR SCRAMBLE_AES
for scrambling using fast AES cypher.  If the keyfile does not exist, it is created.
This function internally calls
.BR scramble_readstate()
and
.BR scrable_init().
Returns 0 if successful.
.BR SCRAMBLE_BLOWFISH
uses blowfish cypher.  While previously widely used, it's no longer recommended, as scrambling
of ipv6 addresses can be very slow.
.P
.EX
.BR "int32_t   scramble_ip4(uint32_t input, int pass_bits)"
.BR "int32_t unscramble_ip4(uint32_t input, int pass_bits)"
.EE
.IP
Scrambles or un-scrambles (input) IP address passing through first (pass_bits); the scrambled
ip address is returned.  Please note that even if (pass_bits) is 0, first few
bits will be passed through to preserve class of the input IP.  Both input and
output IPs are in network byte order.
Note that unscrambling is a costly operation and unscrambling a large number
of different addresses can take a long time.
.PP
.EX
.BR "void   scramble_ip6(struct in6_addr *input, int pass_bits)"
.BR "void unscramble_ip6(struct in6_addr *input, int pass_bits)"
.EE
.IP
Scrambles or un-scrambles IPv6 address pointed to by (input) 
.B "in-place"
, passing through first (pass_bits).  Addresses are in network byte order.
Note that unscrambling is a costly operation and unscrambling a large number
of different addresses can take a long time.
.PP
.EX
.BR "int scramble_readstate(const char *keyfile, scramble_state_t *s)"
.BR "int scramble_savestate(const char *keyfile, const scramble_state_t *s)"
.EE
.IP
These functions can read scrambling keys from keyfile into
memory pointed to by (s), or save/write previously initialized state (s)
to a (keyfile).  After state is read, the library still needs to be 
initialized by calling
.B scramble_init()
Return 0 on success.
.PP
.EX
.BR "int scramble_init(const scramble_state_t *s)"
.EE
.PP
.IP
Initializes library using state pointed by (s).  Returns 0 on success.


.SH SEE ALSO
.BR scramble_ips 
.IP
is a binary for anonymizing textual IP addresses, which comes packaged with this library
.EP
.PP
.SH AUTHORS
The cryptopANT library was written by
.IP "Yuri Pradkin,"
University of Southern California, Information Sciences Institute, CA.
.EP
.LP
The current version is available from "ANT Project"'s Web site at
.LP
.RS
.I http://ant.isi.edu
.RE
.SH BUGS
Please send problems, bugs, questions, desirable enhancements, etc. to:
.LP
.RS
ant@isi.edu
.RE