Ключевые слова: access, attack, background, black, blackboard, board, brush, brushstroke, chalk, chalkboard, color, concept, crack, crime, data, defend, digital, drawing, education, encryption, hack, information, knowladge, learn, learning, lesson, multicolor, overlapped, paint, paintbrush, pin, policy, privacy, protect, protection, safe, safety, school, secrecy, secure, security, study, system, teach, technology, text, texture, web, word,