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When i am going to decrypt my Aes Encrypted zip file in my windows 7 machine then it is showing error "Message length invalid" but it is working fine another windows machine where we have encrypted zip file and file size is 75.1 MB. So kindly tell me why it is happening because it is very critical please give us solutions.

This error is returned when AES Crypt attempts to read a 16 octet cipher block, but the operating system returns only a partial block. In other words, the file has been truncated somehow. If you were to compare these two files, you'd discover they're not exactly the same length.

Try to get the file length down to the exact number of bytes. Be careful about using the file properties window since some information about size isn't the actual file size. If in doubt, use the "direct" command at the command line.

If you're handy at the command line, getting a hash of the two files would tell you if any bytes changed. Here's a tool that will do that: https://www.packetizer.com/security/sha1/