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CyberXplained

Advanced Encryption Standard (AES)

CoreSymmetric

AES Encryption Simulator

AES Encryption Simulator

AES Encryption Simulator

For 256-bit AES, key should be 32 bytes (64 hex characters)

IV should be 16 bytes (32 hex characters)

Cipher Block Chaining (CBC)

PKCS7 adds padding to make the data a multiple of the block size

Larger key sizes provide stronger security

AES CBC Mode

Each block is XORed with the previous ciphertext block before encryption. Requires an IV for the first block.

Block 1Block 2Block 3Cipher 1Cipher 2Cipher 3AESAESAESIV

This simulator uses the CryptoJS library to perform AES encryption and decryption operations.

All operations are performed locally in your browser - no data is sent to any server.

About AES Encryption

The Advanced Encryption Standard (AES) is a symmetric encryption algorithm established by the U.S. National Institute of Standards and Technology (NIST) in 2001. It replaced the older Data Encryption Standard (DES) and is now one of the most widely used encryption algorithms in the world.

Key Features

  • Symmetric key algorithm (same key for encryption and decryption)
  • Block cipher that operates on fixed-size blocks of 128 bits (16 bytes)
  • Supports key sizes of 128, 192, and 256 bits
  • Extremely secure when implemented correctly
  • Efficient in both hardware and software implementations

Encryption Modes

AES can operate in several modes, each with different security properties:

ECB Mode

Electronic Codebook mode encrypts each block independently. Simple but vulnerable to pattern analysis.

CBC Mode

Cipher Block Chaining mode XORs each plaintext block with the previous ciphertext block before encryption.

CTR Mode

Counter mode turns the block cipher into a stream cipher by encrypting sequential counter values.

Security Considerations

  • AES-256 is expected to stay secure against known quantum attacks: Grover's algorithm only halves its effective strength to about 128 bits. AES-128 would drop to about 64 bits, so prefer AES-256 where long-term secrecy matters
  • Proper key management is crucial for security
  • Initialization Vectors (IVs) should be random and never reused
  • ECB mode should be avoided for encrypting more than one block of data
  • Authenticated encryption modes (like GCM) provide integrity protection

Common Applications

  • Secure communications (HTTPS, SSH, VPNs)
  • File and disk encryption
  • Password storage (with proper key derivation)
  • Secure messaging applications
  • Hardware security modules