Summary
FileCrypt is a desktop application designed to securely encrypt and verify file integrity using a custom cryptographic algorithm. Each encrypted file is encapsulated into a ZIP container that stores both the encrypted data and metadata containing hash values computed before and after encryption.
During decryption, FileCrypt validates these hashes to ensure that the file has not been modified or tampered with. If the decrypted content’s hash does not match the stored metadata, the file is flagged as “broken” or compromised.
Problem
Sharing or storing sensitive files publicly often risks modification or corruption—either unintentionally or through tampering. While encryption protects confidentiality, it doesn’t inherently verify data integrity. There was a need for a lightweight tool that could detect file tampering while keeping the encryption workflow simple and self-contained.
Goal / Use Case
- Develop a standalone encryption utility for Windows using C# and .NET.
- Combine encryption and file integrity verification into one streamlined process.
- Generate hash metadata before and after encryption, stored inside a ZIP container with the encrypted file.
- During decryption, automatically compare the stored hash with the newly computed one to verify authenticity.
- Provide clear feedback when a file is corrupted or altered after encryption.
Impact
- Enabled users to safely share encrypted files without fear of silent tampering.
- Simplified cryptographic workflows into a single self-contained package.
- Reinforced understanding of hashing, encryption algorithms, and metadata verification in practical file protection.
- Offered a lightweight yet effective solution for maintaining file authenticity in public or semi-trusted environments.
Development Duration
Developed in approximately 1 weeks using C# and .NET as a personal project focused on practical cryptography. The app demonstrates integration between encryption algorithms, ZIP packaging, and hash-based verification for file authenticity assurance.