You can create the following pre-request script provided your parameters are defined environment variables. You would need to tweak this example if they are defined in some other fashion.
// Import the CryptoJS library with jQuery $.getScript("http://crypto-js.googlecode.com/svn/tags/3.1.2/build/rollups/md5.js", function() { // Access your env variables like this var strstr_1 = environment.variable_1 + environment.variable_2; // Or get your //request Useparameters var thestr_2 CryptoJS= scriptrequest.data["foo"] you+ importedrequest.data["bar"]; // Use the CryptoJS var hash = CryptoJS.MD5(strstr_1 + str_2).toString(); // Set the new environment variable postman.setEnvironmentVariable('hash', hash); }); The importCryptoJS works because jQuery isit's available in Postman (as well as lodash, backbone etc).
Accessing environment variables is easy through the environment object.
Setting environment variables is available through the postman object.
After this pre-request has run you can access the hash variable using the normal {{hash}} shorthand.
Also, you can read here about libraries, variables and properties available in Postman.