Open a Microsoft Excel sheet which been set password, in code not provide “Options” cause “zip: not a valid zip file” about excelize HOT 2 CLOSED

Thanks for your issue. The unencrypted workbook is a compressed file with the ZIP format, but the encrypted workbook is a CFB (OLE) file, which is different from the ZIP format. You will get that error message not only after opening an encrypted workbook without specifying the correct password but also after opening any file format that isn't supported by this library. So I think this error message is expected. Note that, you can roughly determine if a file is in a CFB format by this identifier. I'll close this issue. If you have any questions, please let me know, and you can reopen this anytime.

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Thank you, @xuri, I add a function to judge whether it is an ole format Excel file, and tips it has encrypted must provide password to open it.

func isOleExcel(f io.ReadSeeker) bool {
	oleIdentifier := []byte{0xd0, 0xcf, 0x11, 0xe0, 0xa1, 0xb1, 0x1a, 0xe1}
	buf := make([]byte, len(oleIdentifier))

	_, err := f.Read(buf)

	if err != nil {
		return false
	}

	f.Seek(0, io.SeekStart)

	return bytes.Compare(buf, oleIdentifier) == 0
}

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