(.NET Core C#) Determine if a Zip is Encrypted or Password-Protected

Determines whether or not a zip archive is AES encrypted or password-protected.

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// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

Chilkat.Zip zip = new Chilkat.Zip();

// An encrypted or password-protected zip can be opened
// without specifying the password.  However, the contents
// of the files cannot be unzipped without providing the correct
// password.

bool success = zip.OpenZip("something.zip");
if (success != true) {
    Debug.WriteLine(zip.LastErrorText);
    return;
}

// If the zip is password-protected, meaning that it uses
// the old (insecure) Zip 2.0 encryption, then the
// PasswordProtect property will be true
bool bPwdProt = zip.PasswordProtect;
if (bPwdProt) {
    Debug.WriteLine("This zip is password-protected.");
}

// If the zip is AES encrypted (WinZip compatible) then
// the Encryption property will be equal to 4.
int encValue = zip.Encryption;
if (encValue == 4) {
    Debug.WriteLine("This zip is AES encrypted.");
}

// If the Encryption property = 0, then the zip is NOT
// strong encrypted, and is either password-protected or
// entirely unencrypted, depending on the value of the
// PasswordProtect property.

zip.CloseZip();