Handling Sensitive Data in Memory

Protecting data in memory prevents extraction through memory dumps or debugging.
// Android - Secure memory handling
import java.security.SecureRandom
import java.util.Arrays

class SecureMemoryHandler {
    
    // Secure string that clears itself
    class SecureString(private val chars: CharArray) : AutoCloseable {
        
        fun use(block: (CharArray) -> Unit) {
            try {
                block(chars)
            } finally {
                clear()
            }
        }
        
        override fun close() {
            clear()
        }
        
        private fun clear() {
            Arrays.fill(chars, ' ')
        }
    }
    
    // Secure byte array
    class SecureByteArray(private val bytes: ByteArray) : AutoCloseable {
        
        fun use(block: (ByteArray) -> Unit) {
            try {
                block(bytes)
            } finally {
                clear()
            }
        }
        
        override fun close() {
            clear()
        }
        
        private fun clear() {
            val random = SecureRandom()
            random.nextBytes(bytes) // Overwrite with random data
            Arrays.fill(bytes, 0.toByte())
        }
    }
    
    // Prevent memory swapping for sensitive data
    fun lockMemory(data: ByteArray) {
        // Note: Full memory locking requires native code
        // This is a simplified example
        try {
            // Keep reference to prevent garbage collection
            Runtime.getRuntime().addShutdownHook(Thread {
                Arrays.fill(data, 0.toByte())
            })
        } catch (e: Exception) {
            // Handle error
        }
    }
}