token-decoder.js

// Postman Test Script for Automatic Token Decryption
// Add this script to the "Tests" tab in your Postman request

// Configuration - Change this to match your secret key
const secretKey = "SECRET_KEY"; 

// Parse the response body
const responseBody = pm.response.json();
let decryptedData = null;

// Check if the response contains a token
if (responseBody && responseBody.data) {
    const encryptedToken = responseBody.data;
    
    // Derive a 128-bit key from the secret key string using SHA-256
    function getSecretKeyFromString(keyStr) {
        const hash = CryptoJS.SHA256(keyStr).toString(CryptoJS.enc.Hex);
        // Take the first 32 hex digits (16 bytes) for AES-128
        return CryptoJS.enc.Hex.parse(hash.substring(0, 32));
    }
    
    // Decrypt function matching the React component implementation
    function decrypt(cipherText) {
        try {
            // Generate the proper key from the input string
            const processedKey = getSecretKeyFromString(secretKey);
            
            // Decrypt using the same parameters as the original code
            const decrypted = CryptoJS.AES.decrypt(
                cipherText.trim(), 
                processedKey,
                {
                    mode: CryptoJS.mode.ECB,
                    padding: CryptoJS.pad.Pkcs7,
                }
            );
            
            const decryptedStr = decrypted.toString(CryptoJS.enc.Utf8);
            if (!decryptedStr) {
                throw new Error("Decryption resulted in empty string");
            }
            
            return decryptedStr;
        } catch (error) {
            console.error("Decryption error:", error);
            throw error;
        }
    }
    
    try {
        // Decrypt the token
        decryptedData = decrypt(encryptedToken);
        
        // Store the decrypted data in Postman variables
        pm.variables.set("decryptedToken", decryptedData);
        
        // Try to parse as JSON
        try {
            const jsonData = JSON.parse(decryptedData);
            pm.variables.set("decryptedTokenJSON", JSON.stringify(jsonData, null, 2));
        } catch (e) {
            // Not valid JSON, just use the string version
        }
        
    } catch (error) {
        console.error("Failed to decrypt token:", error);
    }
}

// Create a visualization of the decrypted data
const template = `
<style>
    .container { font-family: Arial, sans-serif; padding: 20px; }
    .header { font-size: 16px; font-weight: bold; margin-bottom: 10px; }
    .content { background-color: #f5f5f5; padding: 15px; border-radius: 5px; white-space: pre-wrap; }
    .original { margin-top: 20px; color: #666; }
</style>

<div class="container">
    <div class="header">Decrypted Response:</div>
    <div class="content">{{decrypted}}</div>
    
    <div class="original">
        <div class="header">Original Response:</div>
        <div class="content">{{original}}</div>
    </div>
</div>
`;

// Prepare the visualization data
let decryptedFormatted;
try {
    const jsonData = decryptedData ? JSON.parse(decryptedData) : null;
    decryptedFormatted = jsonData ? JSON.stringify(jsonData, null, 2) : (decryptedData || "No decrypted data");
} catch (e) {
    decryptedFormatted = decryptedData || "No decrypted data";
}

const visualizationData = {
    decrypted: decryptedFormatted,
    original: JSON.stringify(responseBody, null, 2)
};

// Set the visualization
pm.visualizer.set(template, visualizationData);