Hard drive wipe verification is complex.

Determining with 100% certainty whether a hard drive contains actual meaningful data or just random 1's and 0's can be challenging. When data is overwritten, distinguishing between meaningful data and random patterns becomes difficult, especially if the overwriting process is thorough.
In theory, if you have information about the specific process used to overwrite the data and you know that it was done in a way that completely obliterates the original data, you might have a higher degree of confidence. However, even then, there could be potential challenges.
Several factors contribute to the complexity:

• Data Recovery Techniques: Advanced data recovery techniques might be able to retrieve some remnants of the original data, even if it has been overwritten.
• Encryption: If the original data was encrypted, it might be impossible to determine if the overwritten data is meaningful without the decryption key.
• Unknown Overwriting Algorithm: If you don't have detailed information about the specific algorithm used to overwrite the data, it becomes more challenging to make a definitive assessment.
• Random Data Generation: Truly random data and meaningful data can, in some cases, be indistinguishable without additional context.

In practice, organizations often use secure deletion methods, such as multiple passes of overwriting with random patterns, to make data recovery more difficult. Still, achieving 100% certainty is a difficult task.