Why Does Converting a Byte Array to String and Back Result in Data Loss?

Problems Converting Byte Array to String and Back to Byte Array

Despite numerous discussions on this topic, a persisting challenge remains for some: converting a byte array to a string and back to a byte array without resulting in a mismatched byte array. The issue surfaces when individuals attempt to manipulate encrypted data as strings instead of byte arrays.

In the provided code example, the encryption and decryption processes operate smoothly when using byte arrays. However, when converting the byte array to a string and back, the resulting byte array deviates from the original. Consequently, the decryption process fails. Several string encodings, including UTF-8 and UTF-16, have been tested with no success.

Understanding the Discrepancy

The underlying issue stems from the nature of strings and byte arrays. Strings are designed for representing human-readable text, not raw binary data. When storing encrypted data in strings, it introduces potential discrepancies.

Avoiding Data Loss

To prevent data loss during conversion, it is crucial to use encodings that maintain a one-to-one mapping between bytes and characters. One such encoding is ISO-8859-1, which guarantees that every byte sequence corresponds to a specific character sequence and vice versa.

Optimized Code with ISO-8859-1

To resolve the issue with UTF-16, which fails for two primary reasons, the following code excerpt demonstrates the use of ISO-8859-1:

    String decoded = new String(encryptedByteArray, "ISO-8859-1");
    System.out.println("decoded:" + decoded);

    byte[] encoded = decoded.getBytes("ISO-8859-1"); 
    System.out.println("encoded:" + java.util.Arrays.toString(encoded));

    String decryptedText = encrypter.decrypt(encoded);

The above is the detailed content of Why Does Converting a Byte Array to String and Back Result in Data Loss?. For more information, please follow other related articles on the PHP Chinese website!