Decrypt given data previously encoded with aes-256-ecb cipher algo. AES with 256-bit key in ECB (Electronic Codebook) mode, which encrypts each block independently. Advanced Encryption Standard (AES) was established by NIST in 2001. ECB mode is one of the simplest but least secure modes due to its lack of diffusion. Considered insecure due to patterns being preserved in ciphertext. Not recommended for use. Our decryption process assumes the IV string is prepended in the encoded string during the encryption process. You can not decrypt and get the correct results if the IV or passphrase mismatch occurs between encryption and decryption process.