Anonymizer

Goal: Anonymize IP addresses in Unirec records.

Method: IP addresses in Unirec (source and destination) are anonymized and then sent to output interface.
        CryptoPAn library, which were taken from NfDump source codes, is used.
        By default Rijndael cipher is used as pseudorandom generator,
        but if faster algorithm is needed, MurmurHash3 can be used instead (parameter -M).
        RijdaelCipher comes with CryptoPAn library, and is used by several other anonymization tools,
        anonymized addresses should therefore be exactly the same as if other common tools are used (when the same key is used).
        Usage of MurmurHash3 is our own modofication and since we are not experts on cryptography, we can't
        give any guarantees of non-reversibility of anonymization process. However, it's much faster.
        In both cases, anonymization is prefix-preserving and a anonymization key is required.
        Deanonymization is possible with the correct key (use -d switch).

Input interface: Unirec containing at least:
                 - Source address     (SRC_IP)
                 - Destination addres (DST_IP)

Output interface: Unirec containing the same items as input Unirec, but with anonymized IP addresses.

Algorithm: CryptoPAn tools (http://www.cc.gatech.edu/computing/Telecomm/projects/cryptopan/).

Anonymization key: 32 characters long string or 32B sized hex string starting with 0x.
                   Needs to be specified by one of the following ways:
                   - As a parameter on command line.
                   - Written in a file whose name must be specified on command line.

Parameters: -k KEY     Specify anonymization key.
            -f FILE    Specify file containg anonymization key.
            -S         Disable anonymization of SRC_IP.
            -D         Disable anonymization of DST_IP.
            -M         Use MurmurHash3 instead of Rijndael cipher.
            -d         Switch to de-anonymization mode, i.e. do reverse transofmration of the addresses.