Patent ID: 7991999

Claim:
A block-based media device comprising: an authentication mechanism comprising a processor; the authentication mechanism authenticating a block of data up to a maximum size; a disk header including a first hash H(1,n 1 * . . . *n x+1 ,Y), wherein n 1 . . . n x+1 are selected from a group of integers consisting of 1 and the number of hashes necessary to cover the maximum size of the block of data that can be authenticated by the authentication mechanism such that n 1 <n 2 < . . . n x <n x+1 ; a second hash H(n 1 * . . . *n x−1 +1,n 1 * . . . *n x−1 *m n x ,Y), wherein m is selected from a group of integers consisting of 1 and the number of child nodes of the first hash; a block including; a plurality of third hashes that are children of the second hash block; a plurality of fifth hashes that are children or grandchildren of one of the plurality of third hashes; a data block Y k associated with at least one of the fifth hashes, at least one of the third hashes, the second hash, and the first hash, wherein Y k ; is one of a set of data blocks {Y 1 , Y 2 , . . . , Y N }, wherein H(i,i,Y)=f(Y i ) and f(Y i ) is a one-way function; wherein, in operation, the authentication mechanism uses the first hash, the second hash, at least one of the third hashes, and at least one of the fifth hashes to authenticate the data block Y k .