Online AES encryption and decryption tool supporting multiple cipher modes and key lengths to ensure data security.
Enter content and click Encrypt/Decrypt button
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Worried about sensitive data being stolen during transmission or storage? This tool provides symmetric encryption capabilities based on the Advanced Encryption Standard (AES). It can perform high-strength encryption on text to generate ciphertext, or reverse the process to decrypt valid ciphertext back to its original content. AES is a block cipher algorithm. Its core principle involves dividing data into fixed 128-bit blocks and applying multiple rounds of substitution and permutation to achieve encryption. Decryption uses the same key to perform the reverse operation. The algorithm supports three key lengths: 128-bit, 192-bit, and 256-bit. The longer the key, the higher the security.
How long should an AES encryption key be?
128, 192, or 256 bits. The key length must strictly match the selected mode.
What could cause decryption to fail?
You must ensure that the secret key, IV value, and algorithm mode used during encryption perfectly match the decryption parameters. Any discrepancy will result in an error. For example, CBC mode requires the exact same 16-byte IV value.
Key management is crucial; a leaked key will result in complete data exposure. Encryption and decryption parameters must correspond exactly. When processing Chinese text, using UTF-8 encoding is recommended. For highly sensitive data, we recommend using offline tools.
For encrypted data that requires long-term storage, we recommend using the AES-256-CBC mode and generating a random IV value. Example: Plaintext "Hello World" + Key "32-byte length key" + IV "random 16 bytes" encrypted via AES-256 will typically output a Base64 string in the format "U2FsdGVkX1+qvKDxZ...". When decrypting, the entire parameter chain must be fully restored.
