Скачать или смотреть How to Successfully Encrypt with ECIES in JavaScript and Decrypt in Java/Kotlin

A comprehensive guide on solving encryption discrepancies between JavaScript and Kotlin using the ECIES algorithm. Learn how to implement the correct hashing and AES parameters for seamless encryption and decryption.
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Introduction

Encryption plays a critical role in securing sensitive data, especially when transferring it over the internet. A common challenge developers face is ensuring compatibility between different programming languages when implementing cryptographic algorithms. One such scenario involves encrypting data in JavaScript using the ECIES (Elliptic Curve Integrated Encryption Scheme) algorithm and decrypting it in Java or Kotlin.

This post addresses a specific issue encountered during this process: a Bad Block Exception when using the ECCrypto library in JavaScript to encrypt data and subsequently attempting to decrypt it in Kotlin. We will explore the problem in detail and provide a step-by-step solution to ensure that your encryption and decryption process works seamlessly across these languages.

The Problem

To clarify the situation, here are the main points that led to the Bad Block Exception:

Data was successfully encrypted in JavaScript using the ECCrypto library with the curve secp256k1.

When the encrypted data (ciphertext) was sent to a Kotlin implementation for decryption, an error was encountered.

Using the same encryption and decryption methods solely in Java or JavaScript worked perfectly, indicating a disconnect between the two platforms.

The code snippets that highlight the encryption in JavaScript and the decryption in Kotlin are provided below for reference:

JavaScript Encryption Code

[[See Video to Reveal this Text or Code Snippet]]

Kotlin Decryption Code

[[See Video to Reveal this Text or Code Snippet]]

Understanding the Core Issue

After investigation, the root cause of the mismatch was identified to be differences in the underlying cryptographic implementations between the JavaScript and Java/Kotlin libraries:

The hash algorithm and AES encryption parameters used by the two implementations were inconsistent.

The ECIES implementation in Java's BouncyCastle library was particularly criticized for using weak configurations, including:

AES with a 128-bit key

An insecure hash algorithm

Minimal checks for Message Authentication Code (MAC)

Limited test coverage for edge cases

These issues highlight the importance of ensuring that both encryption and decryption processes use identical configurations to avoid compatibility problems.

The Solution

To overcome the issues present, a custom ECIES implementation was created for use in Java. Below are the notable changes and configurations incorporated into this new implementation:

Key Changes

Hash Algorithm: Implemented SHA-512 for a more secure hashing process.

AES Configuration: Changed to use:

A 256-bit key

AES/CBC/PKCS7Padding mode for better data handling and security.

Updated Java Implementation

The following code snippet provides a simplified overview of how this custom implementation could be structured to align with the ECCrypto library used in JavaScript:

[[See Video to Reveal this Text or Code Snippet]]

Testing and Validation

After implementing the above changes, the encryption and decryption processes across JavaScript and Java/Kotlin were successfully aligned. Here are the testing results:

JavaScript Encryption: Data encrypted with eccrypto was correctly handled.

Kotlin Decryption: Using the new custom implementation, the ciphertext was successfully decrypted without exceptions or issues.

Conclusion

In conclusion, compatibility in cryptographic processes between different programming languages is vital, and ensuring that the parameters align is key to success. This solution addresses the specific issues encountered when using the ECIES algorithm across JavaScript and Java/Kotlin. By following these recommen