The invention relates to a security system especially for security documents, wherein a security element is provided in a carrier plane, that under incident light holographically reconstructs a pattern outside the carrier plane, in which concealed information is stored and having a flat transparent verification element which on flat contact with the security element makes the information stored therein visible. The invention further relates to a security element and a verification element for use in the security system and a security document fitted with the security system. The invention additionally relates to an apparatus and a method for reading out the concealed information which is stored holographically in the pattern reconstructed on the security element under incident light.