OpenSSL gives "iv undefined" for AES-256-ECB

Can anyone spot why this command gives "iv undefined"?

>openssl.exe enc -d -aes-256-ecb -K 8000000000000000000000000000000000000000000000000000000000000001 -in ex3.8_C.bin -out plaintext.bin -nopad
iv undefined

See also Basic AES decryption problem


Solution 1:

It is as it says you did not define the iv

Try like this: -iv 0

openssl enc -aes-128-cbc -e -in test.txt -out output.txt -K 1234567812346578 -iv 0 -p