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I want to decrypt a file that has been encrypted using AES-128 in CBC mode using OpenSSL. I got the “.key” file – which is 32 digits – but when I try to decrypt with OpenSSL, the program asks me for “-iv” and I don't know the IV of that file so it won't decrypt. Is there is any other way to decrypt the file without knowing the IV?
I tried with another file of which I have the correspondent IV and it works, and when I don't supply that IV, the decryption fails too.
By the way: is there anyway to know what type of encryption was used to encrypt a file?