File encryption secures data by converting readable files into unreadable ciphertext using an algorithm and key. This fundamentally changes how the data exists on storage—search tools work by scanning readable content for keywords or patterns, which encrypted data lacks. Since the contents are scrambled, standard search functionalities cannot access the actual text to find matches unless decrypted first.

Practical examples include an individual encrypting personal documents (like tax returns) on their laptop using tools like Veracrypt or BitLocker; standard desktop search will be unable to find text within these files until unlocked. Similarly, a company storing encrypted customer databases on cloud servers cannot perform server-side searches for specific customer names within the data blobs without decrypting them first.

The primary advantage is enhanced security against data breaches. The significant limitation is the loss of searchability for encrypted content—finding specific data within encrypted files requires decrypting entire files or volumes first. Some solutions involve indexing limited, deliberately unencrypted metadata (like filenames). Ethically, while encryption safeguards privacy, it complicates legitimate searches by organizations or law enforcement with due process. Future secure search technologies aim to enable searching encrypted data without full decryption.