100% Client-Side

AES Encryption Tool

Free online AES encryption tool. Encrypt text using AES-128, AES-192, or AES-256 with CBC, ECB, CTR, OFB, and CFB modes directly in your browser. No data leaves your device. — runs 100% in your browser, client-side only. No data is sent to any server. Free to use, no account required.

Free Client-Side No Login No Storage
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AES Decryption Tool Decrypt AES-encrypted ciphertext — supports Base64 and Hex input HMAC Generator Generate HMAC message authentication codes — SHA256, SHA512, SHA1, MD5 RSA Key Pair Generator Generate RSA public & private key pairs — 1024, 2048, or 4096-bit SHA-256 Hash Generator Generate SHA-256 cryptographic hashes instantly — Hex or Base64 output

How to Use the AES Encryption Tool

  1. Enter the text you want to encrypt.
  2. Enter a secret key (password). Use a strong, unique key.
  3. Choose key size: 128, 192, or 256-bit (256 recommended).
  4. Click Encrypt. Copy the output ciphertext.
  5. To decrypt, use the AES Decryption tool with the same key.

What is AES?

AES (Advanced Encryption Standard) is a symmetric block cipher — the same key encrypts and decrypts. It is the most widely used encryption algorithm, adopted by the US government and used in TLS, WPA2, and most secure applications.

Security note: This tool uses AES-GCM mode with a random IV for each encryption. Never reuse the same key for highly sensitive data in production — use a proper key management system.

What is AES Encryption?

AES (Advanced Encryption Standard) is the most widely used symmetric encryption algorithm in the world. Standardised by NIST in 2001, it supports 128, 192, and 256-bit keys. AES is used in TLS/HTTPS, file encryption, VPNs, and virtually every modern security system.

Who Should Use It

Developers handling API secrets, backend engineers protecting sensitive records, security teams validating encryption flows, and students learning practical cryptography.

How to Use the AES Encryption Tool

  1. Paste or type the plaintext you want to protect.
  2. Enter a strong key or passphrase and select the AES mode your application uses.
  3. Generate the ciphertext and copy the output for storage or transport.
  4. Store the key securely in a secret manager, never beside the encrypted payload.

Security note

AES protects confidentiality, but encryption alone does not guarantee integrity. Prefer authenticated encryption modes (such as AES-GCM) and never reuse IVs with the same key.

Common Uses

  • Encrypting sensitive data before storing in a database
  • Encrypting files and text for secure transmission
  • Environment variable and secrets encryption in applications
  • End-to-end encrypted messaging systems

Frequently Asked Questions

What is the difference between AES-128, AES-192, and AES-256?

The numbers refer to the key length in bits. AES-256 uses a longer key and is theoretically more secure, but AES-128 has never been broken in practice and is faster. For most applications, AES-128 or AES-256 are both fine.

What is CBC mode vs other AES modes?

CBC (Cipher Block Chaining) XORs each plaintext block with the previous ciphertext block before encrypting, requiring an IV (Initialisation Vector). GCM mode additionally provides authentication, detecting if ciphertext was tampered with. Prefer AES-GCM for new systems.

Is it safe to encrypt data in the browser?

CipherKit uses the browser's Web Crypto API for AES operations — the same cryptographic library used by HTTPS. The key and plaintext never leave your browser.