Opening an encrypted file requires the correct credentials or key to reverse the encryption process. Encryption transforms the file's contents into scrambled, unreadable data using a specific algorithm. To open it, you need the exact password, passphrase, or decryption key corresponding to the method used to lock the file. This process, called decryption, is typically handled automatically by software that recognizes the encryption method once you provide the correct authentication.

Common examples include entering a password to open a PDF secured with Adobe Acrobat's permissions or supplying the passphrase you set when creating a VeraCrypt encrypted volume. Secure email clients like ProtonMail automatically decrypt messages received with your private key. Industries handling sensitive data, such as finance, healthcare, and legal, frequently encrypt files stored locally (e.g., using tools like AxCrypt or 7-Zip) or in cloud platforms (Microsoft Azure Storage, AWS S3), requiring specific access credentials before files can be opened and used.

The primary advantage is robust data protection against unauthorized access if the file is lost, stolen, or intercepted. Key limitations involve the risk of permanent data loss if credentials are forgotten and potential workflow friction requiring secure credential management. Strong encryption provides significant privacy benefits but necessitates responsible password/key handling. Its importance grows with rising data privacy regulations, making the ability to securely open encrypted files essential for both personal and business data security.