AES Online Encryptor/Decryptor
AES Online Encryption/Decryption tool, supports CBC/ECB/CTR/CFB/OFB modes, 128/192/256-bit keys
About AES Encryption
The Advanced Encryption Standard (AES), originally known as Rijndael, is a specification for the encryption of electronic data established 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 lengths of 128, 192, and 256 bits. Depending on the key length, it performs 10, 12, or 14 rounds of substitution and permutation operations. It effectively protects sensitive data, messages, and files from unauthorized access and is currently one of the most widely used algorithms globally.
Key Features
- Military-Grade Security: Supports AES-256, the industry standard for protecting sensitive data, also approved for encrypting top-secret information.
- Comprehensive Encryption Modes: Fully supports all standard operation modes, including CBC (Recommended), ECB, CTR, OFB, and CFB.
- 100% Local Processing: Your data and keys never leave your browser. All encryption and decryption operations are performed locally using JavaScript.
- Flexible Input/Output: Supports processing plaintext and files. Supports Hex, Base64, and raw binary formats for keys and IVs.
Encryption Modes Explained
- CBC: Cipher Block Chaining (CBC) mode: Each block of plaintext is XORed with the previous ciphertext block before being encrypted. Requires IV, more secure, recommended.
- ECB: Electronic Codebook (ECB) mode: Divides plaintext into fixed-size blocks, each encrypted independently. Does not require IV, but lower security, not recommended for sensitive data.
- CTR: Counter (CTR) mode: Turns a block cipher into a stream cipher, generating a keystream by incrementing a counter. Requires IV, supports parallel encryption, suitable for high-performance scenarios.
- CFB: Cipher Feedback (CFB) mode: Turns a block cipher into a stream cipher, using the previous ciphertext block as input for the next block. Requires IV.
- OFB: Output Feedback (OFB) mode: Turns a block cipher into a stream cipher, feeding the output of the encryption algorithm back to the input. Requires IV.
Security Recommendations
- 1. Use Strong Keys: Keys should be randomly generated, at least 128 bits long, 256 bits recommended.
- 2. Protect Key Security: The key is critical for encryption security; it must be kept safe and not transmitted over insecure channels.
- 3. Use Secure Modes: Recommend using CBC or CTR modes, avoid using ECB mode.
- 4. Rotate Keys Regularly: For long-term systems, encryption keys should be changed periodically.
- 5. Use Unique IV: A different IV should be used for each encryption, even when using the same key.
Usage Scenarios
- Data Transmission: Protecting sensitive data during network transmission
- File Encryption: Encrypting sensitive files stored on disk
- Database Encryption: Encrypting sensitive fields in databases
- Password Protection: Encrypting user passwords and other authentication info
- Communication Encryption: Encrypting instant messaging and email content
Encryption Modes Comparison
| Mode | Security | Speed | Parallel Proc. | Error Propagation | Recommendation |
|---|---|---|---|---|---|
| CBC | High | Medium | Decrypt Only | Adjacent blocks | Most common, suitable for general needs |
| ECB | Low | Fast | Fully Supported | None | Not recommended - Security risks |
| CTR | High | Fast | Fully Supported | None | High performance, supports streaming |
| CFB | High | Medium | Decrypt Only | Adjacent blocks | Suitable for stream encryption |
| OFB | High | Medium | Not Supported | None | Suitable for error tolerance |
Key Length Security Comparison
| Key Length | Bytes | Possible Combinations | Brute-force Time Est. | Performance | Advice |
|---|---|---|---|---|---|
| 128-bit | 16 bytes | 2128 ≈ 3.4×1038 | Billions of years (current tech) | Fastest Benchmark (100%) | Suitable for most commercial apps, provides sufficient security |
| 192-bit | 24 bytes | 2192 ≈ 6.3×1057 | Far beyond universe age (theoretically impossible) | Medium ~80% of AES-128 | Less common, higher security than 128-bit |
| 256-bit | 32 bytes | 2256 ≈ 1.1×1077 | Astronomically impossible (even with all universe energy) | Slower ~60-70% of AES-128 | For highly sensitive data, gov/military use |
Security Note:
AES-128 is considered secure enough to withstand all known attacks. Key length choice should balance security needs and performance. For most applications, AES-128 provides sufficient security, while AES-256 is recommended for highly sensitive data.
Performance Benchmark (AES-NI Acceleration)
Note: Actual performance varies by hardware, implementation, and data size. Chart shows typical benchmarks on modern CPUs with AES-NI support. Without hardware acceleration, performance may drop 10-20x.
Resources
FAQ
Is AES secure?
Yes, AES is considered highly secure. AES-256 is the gold standard, widely used by governments and financial institutions. With current technology, brute-forcing AES is practically impossible.
Difference between CBC and ECB?
ECB (Electronic Codebook) encrypts identical plaintext blocks to identical ciphertext blocks, revealing patterns. CBC (Cipher Block Chaining) uses IV to ensure identical text produces different ciphertext, offering higher security. We recommend CBC or CTR.
What is IV (Initialization Vector)?
IV (Initialization Vector) is used to randomize the encryption process. Even with the same key and plaintext, different IVs produce completely different ciphertext. IV doesn't need to be secret but must be unique (for CBC) or random.
Can I recover data if I lose the key?
No. AES is designed so that data cannot be decrypted without the correct key. There are no backdoors or master keys. If you lose your key, your encrypted data is lost forever.
Is my data uploaded to a server?
No. This tool runs entirely in your web browser using JavaScript. No data, keys, or files are sent to our servers. Your privacy is fully protected.