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Encrypt and Decrypt File Online

This online tool securely encrypts and decrypt files including documents, images, PDFs, and text files in just a few clicks. It follows modern security practices recommended by NIST and OWASP, processing files safely in-memory without requiring any software installation.

To get started, upload your file, optionally add a secret passkey for enhanced protection, and download the encrypted or decrypted file instantly.

File encryption uses AES-256-GCM with PBKDF2-HMAC-SHA256 (100,000 iterations), a random 16-byte salt, a 12-byte IV and a 128-bit authentication tag.

Encrypt File

Protect your file with a matching passkey.

Supported formats: images, documents, and text files.

Selected image preview

After encryption, download the .enc file or copy Base64.

Decrypted image preview

Decrypt File

Restore the original file from its encrypted download.

Ensure the secret key matches the one used during encryption. Upload a file previously encrypted using this tool. Keep its original encrypted filename.

Selected image preview

If decryption fails, the passkey may be incorrect or file corrupted.

Decrypted image preview

File Encryption Tool – Features, Security & Usage

This online file encryption tool uses AES-256 (Advanced Encryption Standard) to securely encrypt and decrypt files. Encryption is performed using modern, authenticated cryptography and secure in-memory processing. The encryption service does not deliberately save uploads; server multipart handling may use temporary storage.

  • AES-256-GCM Military-grade authenticated encryption
  • Server Processing Encryption operates on uploaded bytes
  • PBKDF2 Key Derivation Password strengthened with random salt

Key Features of This File Encryption Tool

  • AES-256 Encryption Industry-standard symmetric encryption used to protect sensitive files.
  • Password-Based Key Derivation A secure encryption key is derived from your password using PBKDF2 with HMAC-SHA256 and a random salt.
  • Authenticated Encryption (AES-GCM) Provides confidentiality and integrity protection, preventing file tampering.
  • In-Memory Processing The encryption service processes uploaded bytes in memory; multipart handling may buffer uploads.
  • No File Storage The encryption service returns results without deliberately saving files.
  • Instant Download Files are available for download immediately after processing.

Choosing the Right Encryption Approach

The best way to encrypt a file depends on your use case, security requirements, and key management strategy. Below are commonly used encryption approaches and where they fit best:

  • AES File Encryption AES-256 is ideal for encrypting documents, images, PDFs, and backups due to its strong security and performance.
  • Password-Based Encryption When encrypting files with passkeys, secure key derivation functions like Argon2 and PBKDF2 are commonly used to derive strong encryption keys.
  • Asymmetric Encryption (RSA) For secure file sharing, public-key encryption like RSA is used to encrypt encryption keys, not entire files.
  • Message Authentication To verify file integrity, cryptographic MACs such as HMAC can be used alongside encryption.
  • Disk-Level Encryption Tools like VeraCrypt, BitLocker, and FileVault are designed for full-disk or volume encryption rather than individual files.

How AES-256 File Encryption Works

AES is a symmetric encryption algorithm, meaning the same secret key is used for both encryption and decryption. AES-256 refers to the use of a 256-bit encryption key, which is currently considered secure against brute-force attacks.

Encryption Flow

  • File Upload File is securely processed in memory
  • Key Derivation Password → PBKDF2 → AES-256 key
  • Encryption AES-GCM encrypts file data
  • Output Encrypted file generated & downloaded

Common File Encryption & Decryption Errors

Wrong Password During Decryption If the password provided during decryption does not match the original password, decryption will fail or produce invalid output.

Fix: Always use the exact same password used during encryption.

Encrypted File Was Modified AES-GCM performs integrity checks. Any modification to the encrypted file (even one byte) will cause decryption to fail.

Fix: Do not rename, edit, compress, or modify encrypted files.

Using Password Encryption for File Sharing Password-based encryption is not ideal for sharing files with multiple recipients.

Fix: Use PGP File Encryption for secure file sharing.

When NOT to Use This Tool

AES vs RSA vs PGP for File Encryption

Feature AES RSA PGP
Large file support Yes No Yes
Password-based Yes No Optional
Multiple recipients No No Yes

Frequently Asked Questions – File Encryption & Decryption

How does this file encryption tool work?

This tool encrypts files using AES-256-GCM, a modern authenticated encryption algorithm. A secure encryption key is derived from your password using PBKDF2 with HMAC-SHA256, along with a random salt and IV. The encrypted output includes all required metadata to allow safe decryption later.

Is my file uploaded to the server?

Yes. Files and passkeys are uploaded to the DevGlan server. The encryption service processes bytes in memory; multipart uploads may be buffered by the server.

What happens if I forget my encryption password?

If the password is lost, the encrypted file cannot be recovered. AES-256 encryption is designed to be computationally infeasible to break without the correct password. There is no password reset or recovery mechanism.

Is this tool safe for encrypting large files?

Yes. AES is specifically designed for encrypting large files efficiently. For secure file sharing with multiple recipients, consider using PGP file encryption.

How is this different from RSA encryption?

RSA is an asymmetric encryption algorithm and is not suitable for encrypting large files. This tool uses AES symmetric encryption, which is fast and efficient for files. RSA is typically used to encrypt AES keys, not file data directly.

Can I verify the integrity of an encrypted file?

Yes. AES-GCM provides built-in authentication. If the encrypted file is modified or corrupted, decryption will fail automatically, preventing tampered data from being recovered.

Which encryption method should I choose for my use case?

Use AES file encryption for password-protected files. Use PGP encryption for secure file sharing. Use RSA only for encrypting small secrets or keys.

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