Securing JPEG2000 (J2K)- The Next Generation Image Compression Standard.ppt

Securing JPEG2000 (J2K)- The Next Generation Image Compression Standard Background JPEG2000 (J2K) is an emerging standard for image compression Achieves state-of-the-art low bit rate compression and has a rate distortion advantage over the original JPEG. Allows to extract various sub-images from a single compressed image codestream, the so called “Compress Once, Decompress Many Ways”. ISO/IEC JTC 29/WG1 Security Working Setup in 2002 Outline Data Structure of J2K Image Codestreams The Authentication Scheme The Access Control Scheme Prototype Demo Data Structure of J2K Image Codestreams Components Each image is decomposed into one or more components, such as R, G, B. Denote components as Ci, i = 1, 2, …, nC. Resolution Resolution-Increments Resolution and Resolution-Increments Precincts Layers Layer-Increments Layers Layer-Increments Packet (Cont.) Packets Progression Orders A J2K codestream can be viewed as a set of series of packets; they are the most fundamental building blocks of a codestream. A packet is uniquely identified by four parameters C, R, P and L, all the packets in a codestream can be sorted with respect to these four parameters in some orders, called Progression Orders. There are five Progression Orders which are LRCP, RLCP, RPCL, CPRL and PCRL respectively. Progression Order J2K Authentication The Merkle Tree A Codestream Example The Merkle Tree For the Example Authentication Verification Authentication Owner constructs a Merkle tree of a codestream and signs the root value. Passes data to a publisher Upon request of a user, publisher sends packets of requested sub-image, signature and SIT. Verification The user re-computes the root value, and verifies it based on the signature. The Optimized Merkle Tree J2K Access Control The Super-Distribution Model Security Classes in a Codestream Security Classes of Resolution-Increments R2 R1 R0 (total ordering) Security Classes of Layer-Increments L2 L1 L0 (total ordering) Security Classes of