Decrypt given data previously encoded with seed-ecb cipher algo. SEED in ECB (Electronic Codebook) mode, where each block of plaintext is encrypted independently. ECB mode is simpler but less secure because identical plaintext blocks yield identical ciphertext blocks. SEED-ECB is not recommended due to the weaknesses of ECB mode in modern cryptography. 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.