Steganographic Online Codec allows you to hide a password encrypted message within the images & photos using AES encryption algorithm with a 256-bit PBKDF2 derived key.
You can use it for free at:
https://www.pelock.com/products/steganography-online-codec
This SDK provides programming access to the codec and its encoding and decoding functions through a WebAPI interface.
Steganography is a term describing the art and science of hiding information by embedding messages within other, seemingly harmless image files.
In this case, the individual bits of the encrypted hidden message are saved as the least significant (LSB) bits in the RGB color components in the pixels of the selected image.
With our steganographic encoder you will be able to conceal any text message in the image in a secure way and send it without raising any suspicion. It will only be possible to read the message after providing valid, decryption password.
The preferred way of Web API SDK installation is via NPM (Node Package Manager).
Run:
npm i steganography-online-codec
Or add this entry:
"dependencies": {
"steganography-online-codec": "latest"
},
directly to your package.json in dependencies section.
The installation package is available at https://www.npmjs.com/package/steganography-online-codec
The installation packages have been uploaded to repositories for several popular programming languages and their source codes have been published on GitHub:
| Repository | Language | Installation | Package | GitHub |
|---|---|---|---|---|
 |
Python | Run pip install steganography-online-codec |
PyPi | Sources |
 |
JavaScript, TypeScript | Run npm i steganography-online-codec or add the following to dependencies section of your package.json file "dependencies": { "steganography-online-codec": "latest" }, |
NPM | Sources |
If you don't want to use Python module, you can import directly from the file:
from pelock.steganography_online_codec import *"use strict";
/******************************************************************************
*
* Steganography Online Codec WebApi interface usage example.
*
* In this example shows how to hide an encrypted secret message in an image file.
*
* Version : v1.00
* Language : JavaScript
* Author : Bartosz Wójcik (original example)
* Project : https://www.pelock.com/products/steganography-online-codec
* Homepage : https://www.pelock.com
*
* @link https://www.pelock.com/products/steganography-online-codec
* @copyright Copyright (c) 2020-2025 PELock LLC
* @license Apache-2.0
*
/*****************************************************************************/
// include Steganography Online Codec module
import { SteganographyOnlineCodec, Errors } from 'steganography-online-codec';
// or if tested locally use:
//import { SteganographyOnlineCodec, Errors } from '../src/SteganographyOnlineCodec.mjs';
// create Steganography Online Codec class instance (we are using our activation key)
const mySteganographyOnlineCodec = new SteganographyOnlineCodec('YOUR-WEB-API-KEY');
// encode a hidden message (encrypted with your password) within an image file
(async () => {
const inputFile = 'input_file.jpg';
const secretMessage = 'Secret message';
const password = 'Pa$$word';
const outputFile = 'output_file_with_hidden_secret_message.png';
try {
const result = await mySteganographyOnlineCodec.encode(inputFile, secretMessage, password, outputFile);
// result object holds the encoding results as well as other information
console.log('Secret messaged encoded and saved to the output PNG file.');
} catch (err) {
console.error('Encoding failed:', err.error_message || err.message || String(err));
}
})();"use strict";
/******************************************************************************
*
* Steganography Online Codec WebApi interface usage example.
*
* In this example, we will see how to hide an encrypted message in an
* image file using our codec.
*
* Version : v1.00
* Language : JavaScript
* Author : Bartosz Wójcik
* Project : https://www.pelock.com/products/steganography-online-codec
* Homepage : https://www.pelock.com
*
* @link https://www.pelock.com/products/steganography-online-codec
* @copyright Copyright (c) 2020-2025 PELock LLC
* @license Apache-2.0
*
/*****************************************************************************/
// include Steganography Online Codec module
import { SteganographyOnlineCodec, Errors } from 'steganography-online-codec';
// or if tested locally use:
//import { SteganographyOnlineCodec, Errors } from '../src/SteganographyOnlineCodec.mjs';
// create Steganography Online Codec class instance (we are using our activation key)
const mySteganographyOnlineCodec = new SteganographyOnlineCodec('YOUR-WEB-API-KEY');
// encode a hidden message within the source image file
(async () => {
// full version image size limit is set to 10 MB (demo 50 kB max)
// supported image formats are PNG, JPG, GIF, BMP, WBMP, GD2, AVIF, WEBP (mail me for more)
const inputFilePath = 'input_file.webp';
// full version message size is unlimited (demo 16 chars max)
const secretMessage = 'Secret message';
// full version password length is 128 characters max (demo 8 chars max)
const password = 'Pa$$word';
// where to save encoded image with the secret message
const outputFilePath = 'output_file_with_hidden_secret_message.png';
try {
// encode a hidden message (encrypted with your password) within an image file
const result = await mySteganographyOnlineCodec.encode(inputFilePath, secretMessage, password, outputFilePath);
// result object holds the encoding results as well as other information
const versionType = result.license && result.license.activationStatus ? 'full' : 'demo';
console.log(`You are running in ${versionType} version`);
console.log(`Secret messaged encoded and saved to ${outputFilePath}`);
if (result.license && result.license.usagesCount !== undefined) {
console.log(`Remaining number of usage credits - ${result.license.usagesCount}`);
}
} catch (err) {
const errorCode = err.error;
switch (errorCode) {
case Errors.INVALID_INPUT:
console.log(`Invalid input file ${inputFilePath} or file doesn't exist`);
break;
case Errors.MESSAGE_TOO_LONG:
console.log('Message is too long for the provided image file, use larger file');
break;
case Errors.IMAGE_TOO_BIG:
console.log(`Image file is too big, current limit is set to ${err.raw?.limits?.maxFileSize ?? 'unknown'}`);
break;
case Errors.LIMIT_MESSAGE:
console.log(`Message is too long, current limit is set to ${err.raw?.limits?.maxMessageLen ?? 'unknown'}`);
break;
case Errors.LIMIT_PASSWORD:
console.log(`Password is too long, current limit is set to ${err.raw?.limits?.maxPasswordLen ?? 'unknown'}`);
break;
case Errors.INVALID_PASSWORD:
console.log('Invalid password');
break;
default:
console.log(`An error occurred: ${err.error_message ?? `Error code ${errorCode}`}`);
}
}
})();"use strict";
/******************************************************************************
*
* Steganography Online Codec WebApi interface usage example.
*
* In this example, we will see how to extract a previously encrypted & hidden
* secret message from an image file.
*
* Version : v1.00
* Language : JavaScript
* Author : Bartosz Wójcik
* Project : https://www.pelock.com/products/steganography-online-codec
* Homepage : https://www.pelock.com
*
* @link https://www.pelock.com/products/steganography-online-codec
* @copyright Copyright (c) 2020-2025 PELock LLC
* @license Apache-2.0
*
/*****************************************************************************/
// include Steganography Online Codec module
import { SteganographyOnlineCodec, Errors } from 'steganography-online-codec';
// or if tested locally use:
//import { SteganographyOnlineCodec, Errors } from '../src/SteganographyOnlineCodec.mjs';
// create Steganography Online Codec class instance (we are using our activation key)
const mySteganographyOnlineCodec = new SteganographyOnlineCodec('YOUR-WEB-API-KEY');
// extract a hidden message from the previously encoded image file
(async () => {
// full version image size limit is set to 10 MB (demo 50 kB max)
// supported image format is PNG and only PNG!
const inputFilePath = 'output_file_with_hidden_secret_message.png';
// full version password length is 128 characters max (demo 8 chars max)
const password = 'Pa$$word';
try {
// extract a hidden message from the image (PNG files only)
const result = await mySteganographyOnlineCodec.decode(inputFilePath, password);
// result object holds the decoding results as well as other information
console.log(`You are running in ${result.license?.activationStatus ? 'full' : 'demo'} version`);
console.log(`Secret message is "${result.message}"`);
if (result.license && result.license.usagesCount !== undefined) {
console.log(`Remaining number of usage credits - ${result.license.usagesCount}`);
}
} catch (err) {
switch (err.error) {
case Errors.INVALID_INPUT:
console.log(`Invalid input file ${inputFilePath} or file doesn't exist`);
break;
case Errors.IMAGE_TOO_BIG:
console.log(`Image file is too big, current limit is set to ${err.raw?.limits?.maxFileSize ?? 'unknown'}`);
break;
case Errors.LIMIT_MESSAGE:
console.log(`Extracted message is too long, current limit is set to ${err.raw?.limits?.maxMessageLen ?? 'unknown'}`);
break;
case Errors.LIMIT_PASSWORD:
console.log(`Password is too long, current limit is set to ${err.raw?.limits?.maxPasswordLen ?? 'unknown'}`);
break;
case Errors.INVALID_PASSWORD:
console.log('Invalid password');
break;
default:
console.log(`An error occurred: ${err.error_message ?? String(err)}`);
}
}
})();"use strict";
/******************************************************************************
*
* Steganography Online Codec WebApi interface usage example.
*
* In this example we will verify our activation key status.
*
* Version : v1.00
* Language : JavaScript
* Author : Bartosz Wójcik
* Project : https://www.pelock.com/products/steganography-online-codec
* Homepage : https://www.pelock.com
*
* @link https://www.pelock.com/products/steganography-online-codec
* @copyright Copyright (c) 2020-2025 PELock LLC
* @license Apache-2.0
*
/*****************************************************************************/
// include Steganography Online Codec module
import { SteganographyOnlineCodec, Errors } from 'steganography-online-codec';
// or if tested locally use:
//import { SteganographyOnlineCodec, Errors } from '../src/SteganographyOnlineCodec.mjs';
// create Steganography Online Codec class instance (we are using our activation key)
const mySteganographyOnlineCodec = new SteganographyOnlineCodec('YOUR-WEB-API-KEY');
// login to the service
(async () => {
try {
const result = await mySteganographyOnlineCodec.login();
// result object holds the information about the license & current limits
const versionType = result.license && result.license.activationStatus ? 'full' : 'demo';
console.log(`You are running in ${versionType} version`);
// information about the current license
if (result.license && result.license.activationStatus) {
console.log(`Registered for - ${result.license.userName}`);
const licenseType = result.license.type === 0 ? 'personal' : 'company';
console.log(`License type - ${licenseType}`);
console.log(`Total number of purchased usage credits - ${result.license.usagesTotal}`);
console.log(`Remaining number of usage credits - ${result.license.usagesCount}`);
}
// current limits (different for DEMO and FULL versions)
if (result.limits) {
console.log(`Max. password length - ${result.limits.maxPasswordLen}`);
const msgLen = result.limits.maxMessageLen === -1 ? 'unlimited' : result.limits.maxMessageLen;
console.log(`Max. message length - ${msgLen}`);
console.log(`Max. input image file size - ${mySteganographyOnlineCodec.convert_size(result.limits.maxFileSize)}`);
}
} catch (err) {
console.error(`Login failed: ${err.error_message || String(err)}`);
}
})();If you are interested in the Steganography Online Codec Web API or have any questions regarding SDK packages, technical or if something is not clear, please contact me. I'll be happy to answer all of your questions.
Bartosz Wójcik
- Visit my site at — https://www.pelock.com
- X — https://x.com/PELock
- GitHub — https://github.com/PELock