CRYPTO Module

Daniel-Constantin Mierla

   <miconda@gmail.com>

Edited by

Daniel-Constantin Mierla

   <miconda@gmail.com>

   Copyright © 2016 asipto.com
     __________________________________________________________________

   Table of Contents

   1. Admin Guide

        1. Overview
        2. Dependencies

              2.1. Kamailio Modules
              2.2. External Libraries or Applications

        3. Parameters

              3.1. salt (str)
              3.2. register_callid (int)

        4. Functions

              4.1. crypto_aes_encrypt(text, key, res)
              4.2. crypto_aes_decrypt(text, key, res)

   List of Examples

   1.1. Set salt parameter
   1.2. Set register_callid parameter
   1.3. crypto_aes_encrypt usage
   1.4. crypto_aes_decrypt usage

Chapter 1. Admin Guide

   Table of Contents

   1. Overview
   2. Dependencies

        2.1. Kamailio Modules
        2.2. External Libraries or Applications

   3. Parameters

        3.1. salt (str)
        3.2. register_callid (int)

   4. Functions

        4.1. crypto_aes_encrypt(text, key, res)
        4.2. crypto_aes_decrypt(text, key, res)

1. Overview

   This module provides various cryptography tools for use in Kamailio
   configuration file.

   It relies on OpenSSL libraries for cryptographic operations (libssl,
   libcrypto).

2. Dependencies

   2.1. Kamailio Modules
   2.2. External Libraries or Applications

2.1. Kamailio Modules

   The following modules must be loaded before this module:
     * none.

2.2. External Libraries or Applications

   The following libraries or applications must be installed before
   running Kamailio with this module loaded:
     * libcrypto - part of OpenSSL project

3. Parameters

   3.1. salt (str)
   3.2. register_callid (int)

3.1. salt (str)

   A keyword to generate salt for encryption. It must be at least 8 chars
   long. If set to empty, no salt is used for encryption.

   The salt is a binary array that is appended to the encryption password
   for better protection against dictionary attacks. Same salt and
   password need to be when encrypting and decrypting.

   Default value is "..." (see code).

   Example 1.1. Set salt parameter
...
modparam("crypto", "salt", "l0Bh2M8a")
...

3.2. register_callid (int)

   Set it to 1 in order to register a callback to core for generation of
   callid values for requests generated by Kamailio tm module.

   This callid generator uses libssl random and hashing functions for
   generating RFC 4122 version 4 UUID with high quality entropy. It is
   useful when wanting to have new callids that cannot be predicted from
   previous values.

   Default value is 0.

   Example 1.2. Set register_callid parameter
...
modparam("crypto", "register_callid", 1)
...

4. Functions

   4.1. crypto_aes_encrypt(text, key, res)
   4.2. crypto_aes_decrypt(text, key, res)

4.1.  crypto_aes_encrypt(text, key, res)

   Encrypts the text with the key using AES encryption algorithm. The
   result is encoded in base64 format and stored in res. The parameter res
   must be a read-write variables. The parameters text and key can be
   static strings or strings with variables (dynamic strings).

   This function can be used from ANY_ROUTE.

   Example 1.3. crypto_aes_encrypt usage
...
crypto_aes_encrypt("$rb", "my-secret-key", "$var(encrypted)");
...

4.2.  crypto_aes_decrypt(text, key, res)

   Decrypts the text with the key using AES encryption algorithm. The text
   has to be encoded in base64 format. The parameter res must be a
   read-write variables. The parameters text and key can be static strings
   or strings with variables (dynamic strings).

   This function can be used from ANY_ROUTE.

   Example 1.4. crypto_aes_decrypt usage
...
crypto_aes_decrypt("$var(encrypted)", "my-secret-key", "$var(text)");
...
