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Security

Text Encrypt / Decrypt

Encrypt text messages securely with AES-256 GCM / CBC, or play with classic ciphers like Caesar and Vigenère.

Cipher Algorithm

Derived using PBKDF2 with 100,000 iterations to guard against brute-force attacks.

All text encryption processes run 100% locally in browser RAM. Secret keys, passwords, and message contents are processed entirely client-side and never touch any server logs.

In an era where communications are constantly tracked and data leaks are regular occurrences, protecting private memos, credentials, and configuration scripts is paramount. Simply storing secret information in plain text leaves it vulnerable to local scrapers and network sniffers. A text encryption and decryption tool solves this issue by converting human-readable messages into unintelligible ciphertext. Our free browser utility supports various modern and classic ciphers—ranging from industry-standard AES-256 GCM to educational ciphers like Caesar and Vigenère—allowing you to easily encode sensitive text locally with maximum security.

What is Text Encryption and Decryption?

Encryption is the process of converting readable text (known as plaintext) into an unreadable scrambled form (known as ciphertext) using a mathematical algorithm and a secret key. Decryption is the reverse process, translating the scrambled ciphertext back into the original plaintext using the correct matching key.

Symmetric encryption relies on a single shared secret key for both locking and unlocking data. Because the key must remain confidential, all processing in our tool runs entirely locally in client-side memory using the secure Web Crypto API, ensuring your master key never travels across the web.

Understanding the Supported Ciphers

Our tool supports multiple encryption algorithms to satisfy both high-security developer specifications and legacy encodings:

  • AES-GCM (Advanced Encryption Standard - Galois/Counter Mode): Highly recommended for modern security. AES-GCM is an Authenticated Encryption with Associated Data (AEAD) algorithm. It not only scrambles the text but also appends an authentication tag. If the ciphertext or key is altered in transit by even a single bit, decryption will fail immediately. This prevents tampering and replay attacks.
  • AES-CBC (Advanced Encryption Standard - Cipher Block Chaining): A classic, robust mode of AES. Each block of plaintext is XORed with the previous ciphertext block before being encrypted. It offers exceptional security but does not feature native authentication verification like GCM.
  • Caesar Cipher: One of the earliest known ciphers, named after Julius Caesar. It shifts each letter in the message by a fixed number of positions (the shift key) down the alphabet. While easily crackable, it serves as a wonderful educational introduction to cryptography.
  • Vigenère Cipher: A historical method of encrypting alphabetic text by using a series of interwoven Caesar ciphers, based on the letters of a keyword. It resists basic frequency analysis better than Caesar, though it is still insecure by modern computing standards.

The Importance of Robust Key Derivation (PBKDF2)

Simple passwords typed by humans lack sufficient entropy (randomness) to be used directly as 256-bit AES encryption keys. To solve this, our tool implements PBKDF2 (Password-Based Key Derivation Function 2).

When you enter a password, the tool generates a unique random 128-bit salt and hashes the password with it 100,000 times using SHA-256. This math-intensive process creates a high-entropy 256-bit cryptographic key and throttles brute-force attempts. The salt and dynamic IV are prepended to the ciphertext and formatted as a clean, shareable Base64 string.

Frequently Asked Questions

Can someone decrypt my AES-GCM message without my password?
No. AES-256 is mathematically secure and approved by governments and banks worldwide. Without your master passphrase, decrypting the ciphertext is virtually impossible with modern computing power, as brute-forcing a 256-bit key would take trillions of years.
Why does the encrypted string change every time I click encrypt?
To ensure maximum security, the generator creates a fresh, random salt and Initialization Vector (IV) for every single encryption. Even if you encrypt the exact same text with the exact same password, the output Base64 string will look completely different, preventing attackers from recognizing repeating message patterns.
Are Caesar and Vigenère ciphers secure?
No. Caesar and Vigenère ciphers are historical algorithms that can be cracked in milliseconds using automated frequency analysis or basic computer solvers. They should only be used for educational purposes, puzzles, or non-critical formatting. For secure data, always use AES-GCM or AES-CBC.