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What Is an Encrypted Notepad?

An encrypted notepad lets you protect sensitive text — passwords, private notes, API keys, personal information — by encrypting it with a passphrase before storing or sharing it. This tool uses AES-256-GCM, the same encryption standard used by governments and financial institutions, implemented entirely in your browser using the Web Crypto API. No data is ever sent to a server.

How the Encryption Works

When you click "Encrypt," the tool generates a random 16-byte salt and 12-byte initialization vector (IV). Your passphrase is fed through PBKDF2 with 100,000 iterations of SHA-256 to derive a 256-bit AES key. The text is then encrypted with AES-GCM, which provides both confidentiality and integrity verification. The salt, IV, and ciphertext are combined and Base64-encoded for easy copying. To decrypt, the same passphrase recreates the identical key through PBKDF2 and reverses the process.

How to Use This Tool

  1. Enter a strong passphrase — Use a passphrase you can remember but others cannot guess. Longer passphrases are exponentially more secure.
  2. Type or paste your text — Enter the sensitive text you want to protect in the text area.
  3. Click Encrypt — The tool encrypts your text instantly. Copy the encrypted output or save it as a file.
  4. To decrypt — Switch to Decrypt mode, paste the encrypted text, enter the same passphrase, and click Decrypt.

Use Cases

Store encrypted notes in cloud storage services without trusting them with your content. Send sensitive information through email or chat by encrypting it first and sharing the passphrase through a separate channel. Keep API keys, recovery codes, or personal information in an encrypted format on your own device. Back up sensitive documents with an additional encryption layer beyond your disk encryption.

Frequently Asked Questions

How does this encrypted notepad work?+
This tool uses your browser's built-in Web Crypto API to encrypt text with AES-256-GCM. Your passphrase is converted to a cryptographic key using PBKDF2 with 100,000 iterations. Everything happens locally — nothing is sent to any server, and nothing is stored or logged.
Is it safe to encrypt text in the browser?+
Yes. The Web Crypto API provides cryptographically secure operations native to your browser. No data is transmitted, stored, or logged. The encrypted output cannot be decrypted without the exact passphrase.
What happens if I forget my passphrase?+
There is no recovery mechanism. AES-256-GCM encryption is designed so that without the correct passphrase, the data is permanently unrecoverable. Always store your passphrase in a password manager.
Can I use this to share encrypted messages?+
Yes. Encrypt your message, copy the output, and send it through any channel (email, chat, etc.). Share the passphrase through a different channel. The recipient can use this same tool to decrypt it.

Built by Derek Giordano · Part of Ultimate Design Tools