AES Encryption/Decryption Tool
Professional Advanced Encryption Standard (AES) tool supporting 128/192/256-bit keys and multiple modes (CBC, ECB, CTR). All processing is done locally in your browser for maximum privacy.
About AES Encryption
The Advanced Encryption Standard (AES), originally known as Rijndael, is a specification for the encryption of electronic data establishment by the U.S. National Institute of Standards and Technology (NIST) in 2001. AES is a symmetric-key algorithm, meaning the same key is used for both encrypting and decrypting the data.
AES operates on a fixed block size of 128 bits and supports key sizes of 128, 192, and 256 bits. Depending on the key size, it performs 10, 12, or 14 rounds of substitution and permutation operations. It allows you to secure sensitive data, messages, and files against unauthorized access, making it one of the most popular algorithms used worldwide.
Key Features
- <strong>Military-Grade Security:</strong> Supports AES-256, the industry standard for securing sensitive data approved by NSA for top-secret information.
- <strong>Comprehensive Modes:</strong> Full support for all standard modes of operation including CBC (recommended), ECB, CTR, OFB, and CFB.
- <strong>100% Client-Side:</strong> Your data and keys never leave your browser. Encryption and decryption happen locally using JavaScript.
- <strong>Versatile Input/Output:</strong> Process both plain text and files. Support for Hex, Base64, and raw binary formats for keys and IVs.
Encryption Modes
- CBC: CBC (Cipher Block Chaining): Each plaintext block is XORed with the previous ciphertext block before encryption. Requires IV, more secure, recommended.
- ECB: ECB (Electronic Codebook): Divides plaintext into fixed-size blocks, each encrypted independently. No IV needed, but less secure, not recommended for sensitive data.
- CTR: CTR (Counter): Converts block cipher to stream cipher by incrementing a counter to produce keystream. Requires IV, supports parallel encryption, suitable for high-performance scenarios.
- CFB: CFB (Cipher Feedback): Converts block cipher to stream cipher, using previous ciphertext block as input for next block. Requires IV.
- OFB: OFB (Output Feedback): Converts block cipher to stream cipher, feeding encryption output back to input. Requires IV.
- RAW: RAW (Single Block): Directly encrypts a single block (16 bytes) without any mode operation or padding. For educational/debugging purposes only.
Encryption Mode Comparison
| Mode | Security | Speed | Parallel Processing | Error Propagation | Recommendation |
|---|---|---|---|---|---|
| CBC | High | Medium | Decrypt Only | Limited to Adjacent Blocks | Most widely used, suitable for general encryption needs |
| ECB | Low | Fast | Full Support | No Propagation | Not Recommended - Has security vulnerabilities |
| CTR | High | Fast | Full Support | No Propagation | Suitable for high-performance scenarios, supports streaming |
| CFB | High | Medium | Decrypt Only | Limited to Adjacent Blocks | Suitable for stream encryption scenarios |
| OFB | High | Medium | Not Supported | No Propagation | Suitable for scenarios requiring error tolerance |
Security Recommendations
- 1. Use strong keys: Keys should be randomly generated with a minimum length of 128 bits, 256 bits recommended.
- 2. Protect keys: Keys are critical for encryption security and must be kept secure, never transmitted over insecure channels.
- 3. Use secure modes: CBC or CTR modes are recommended, avoid ECB mode.
- 4. Rotate keys regularly: For long-term systems, encryption keys should be rotated periodically.
- 5. Use unique IVs: Use a different IV for each encryption, even with the same key.
Key Length Security Comparison
| Key Length | Bytes | Possible Key Combinations | Brute Force Time Estimate | Performance | Usage Recommendation |
|---|---|---|---|---|---|
| 128-bit | 16 bytes | 2128 ?3.4×1038 | Billions of years (using current technology, assuming 10^18 keys/second) |
Fastest
Baseline (100%)
|
Suitable for most commercial applications, provides sufficient security |
| 192-bit | 24 bytes | 2192 ?6.3×1057 | Far exceeds the age of the universe (theoretically impossible) |
Medium
~80% of AES-128
|
Rarely used, provides higher security than 128-bit |
| 256-bit | 32 bytes | 2256 ?1.1×1077 | Astronomically impossible (even with all energy in the universe) |
Slower
~60-70% of AES-128 (with AES-NI)
|
Suitable for highly sensitive data, government/military applications |
Security Note:
AES-128 is already considered secure enough to resist all known attacks. The choice of key length should balance security requirements with performance considerations. For most applications, AES-128 provides sufficient security, while AES-256 is recommended for highly sensitive data. Performance differences are more pronounced with hardware acceleration (AES-NI).
Performance Benchmark (Hardware AES-NI enabled)
Note: Actual performance varies by hardware, implementation, and data size. Values shown are typical benchmarks on modern CPUs with AES-NI instruction support. Without hardware acceleration, performance may be 10-20x slower.
Use Cases
- Data transmission encryption: Protect sensitive data during network transmission
- File encryption: Encrypt sensitive files stored on disk
- Database encryption: Encrypt sensitive fields in databases
- Password protection: Encrypt user passwords and authentication information
- Communication encryption: Encrypt instant messaging and email content
References
Frequently Asked Questions
Is AES encryption secure?
Yes, AES is considered highly secure. AES-256 is the gold standard for encryption and is used by governments and financial institutions worldwide. It is practically unbreakable by brute force with current technology.
What is the difference between CBC and ECB modes?
ECB (Electronic Codebook) encrypts identical blocks of text into identical cipher blocks, which can reveal patterns in the data. CBC (Cipher Block Chaining) uses an IV to ensure that identical text produces different ciphertext, making it much more secure. We recommend using CBC or CTR mode.
What is an Initialization Vector (IV)?
An IV is a random value used to ensure that the same plaintext encrypted with the same key produces different ciphertext each time. It prevents attackers from detecting patterns. The IV does not need to be secret, but it must be unique for each encryption operation.
Can you recover my data if I lose the key?
No. AES is designed so that without the correct key, the data cannot be decrypted. There is no backdoor or master key. If you lose your key, your encrypted data is irretrievably lost.
Is my data uploaded to your server?
No. This tool runs entirely in your web browser using JavaScript. No data, keys, or files are ever sent to our servers. Your privacy is completely protected.
Related Tools
DES/3DES Encryption/Decryption
Encrypt and decrypt using DES and 3DES algorithms with multiple modes and padding options
RSA Encryption/Decryption
Use RSA asymmetric encryption for public key encryption, private key decryption, digital signing and verification
SHA Hash Generator
Online SHA hash generator supporting SHA-1, SHA-256, SHA-384, SHA-512 algorithms
Base64 Encoder/Decoder
Quickly encode and decode Base64 strings, supporting both text and file conversion
Password Generator
Generate strong, secure random passwords with customizable length, character types, strength indicator, and batch generation
SM Cryptography Tools
Chinese national standard cryptography tools supporting SM2 public key cipher, SM3 hash, and SM4 block cipher