A bulletproof vest is read as heavy emotional defence against words or people that feel threatening. Tradition takes it as a sign of feeling under pressure, and of guarding the heart closely.
Does the traditional reading fit your dream, or did it mean something else to you?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.