The article linked above includes 'References' to two further articles at Apple about the situation. This problem was written up as a CVE (Common Vulnerabilities and Exposures), CVE-2015-5901. Because of the nature of how SSDs write and erase data, there is no guarantee that a 'Secure Erase' actually removes the targeted data. The reason Apple removed 'Secure Empty Trash' in El Capitan is, in part, related to the nature of SSDs (Solid State Drives), which are becoming ubiquitous in computing devices.

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Provides a warning dialog before files are erased (Press the Option key to bypass this warning).

Erases files dropped on the application icon.

Implements the Gutmann Method via SRM to remove files.

Note: Permanent Eraser is intended to erase files from mechanical hard drives, but is not intended for use on modern SSDs.

Once your data has been erased, it can no longer be read through traditional means. This utility overwrites your data multiple times, scrambles the original file name, and truncates the file size to nothing before Permanent Eraser finally unlinks it from the system. Permanent Eraser provides additional wiping methods such as the 3-pass DoE or 35-pass Gutmann algorithms. DoD pattern of overwriting data seven times. Beginning with OS X 10.3, Apple enhanced its security by introducing the Secure Empty Trash feature, which follows the U.S. When you normally delete your files in macOS / OS X, the operating system is only forgetting where those particular files are placed, while the data still physically remains on the drive.

Permanent Eraser allows you to securely delete files.

What is secure empty trash mac