The present invention is a peptide lock that comprises at least one peptide that is genetically encoded into the Adeno-associated virus (AAV) capsid that block biologically active domains on the virus capsid surface. The peptide lock, can be processed by biological enzymes to restore biological behavior of the capsid-displayed domains, thus ‘decoding the lock’ or opening the lock. A method of forming the peptide lock comprises providing at least one peptide, providing an Adeno-associated virus capsid and genetically inserting the at least one peptide into the Adeno-associated virus capsid to block the biologically active domains on the virus capsid surface.