Unsupported Encryption Method

If you received this message while extracting or testing files in a Zip file, one or more of the files is encrypted using a method that is unknown to your version of WinZip®.

When this message is encountered, it is always possible that the Zip file is damaged. If possible, obtain a fresh copy of the file (e.g., by re-downloading it) and try again.

Assuming that the correct password is supplied, WinZip 9.0 or later is able to decrypt files that have been encrypted using the following encryption methods:

  • Traditional ZIP 2.0 encryption.
  • AES-encrypted files in the AE-2 encryption format used for very small files and supported by WinZip 9.0 or later and compatible Zip utilities.
  • AES-encrypted files in the AE-1 encryption format supported by WinZip 9.0 or later and by some compatible Zip utilities.
  • Password-protected AES-encrypted files in the PKZIP Strong Encryption Specification format used by PKZIP 6.0. (Note that WinZip does not have support for PKZIP Strong Encryption Specification files that are encrypted with RC2, RC4, DES, or 3DES, or that use certificate-based encryption as opposed to password encryption.)

Please contact us at help@winzip.com if you have any additional questions about the encryption methods supported by WinZip.