The OpenSSH private key is actually not a private key and is simply just base64.
We decode it to get a long useless message and 2 hex strings.
If we decode these hex strings we get,
ineedtoopenlocks
and initialisation12
Decoding the binary gets us a long hex string.
Looking at initialisation, I immediately thought of AES. Since an IV is provided, we can assume it is AES-CBC, so I just used cyberchef to
decrypt and get the flag.