US 8,819,361 B2 · Retaining verifiability of extracted data from signed archives

Abstract

The objects of an archive may be verified with a cryptographic signature stored in the archive. However, when an object is extracted, the authentication involves re-authenticating the entire archive, re-extracting the object, and comparing the extracted object with the current object, which is inefficient or unachievable if the archive is unavailable. Instead, the archive may include a block map signed with the signature and comprising hashcodes for respective blocks of the objects of the archive. When an object is extracted, the signature and block map may also be extracted and stored as objects outside of the archive. The extracted signature and block map may later be verified by authenticating the signature, verifying the block map with the signature, and matching the hashcodes of the block map with those of the blocks of the extracted objects, thus enabling a more efficient and portable verification of extracted object with extracted authentication credentials.

Claims20

Dependent claims

A method of generating an archive comprising at least one block using a device having a processor, a verifier algorithm, and a signing algorithm, the method comprising:

executing on the processor instructions configured to:
for respective blocks, using the verifier algorithm, calculate a block verifier of the block;
generate a block map comprising the block verifiers of respective blocks;
using the verifier algorithm, calculate a block map verifier of the block map;
using the signing algorithm, generate a signature including the block map verifier;
and
generate an archive comprising the blocks, the block map, and the signature.

4 more elements

A method of verifying, using a device having a processor, blocks of an archive including a signature and a block map comprising block verifiers of the blocks of the archive, the method comprising:

executing on the processor instructions configured to:
upon receiving a request to extract at least one selected block from the archive:
extract the selected blocks, the block map, and the signature, and
store the selected blocks, the block map, and the signature outside of the archive;
and
upon receiving a request to verify at least one extracted block:
identify an extracted signature including an extracted block map verifier and an extracted block map for the extracted blocks;
using the signing algorithm, authenticate the extracted signature;
using the verifier algorithm, verify the extracted block map with the block map verifier;
and
using the verifier algorithm, verify the extracted blocks with the block verifier.

8 more elements

Dependencies are inferred from the claim text.

Retaining verifiability of extracted data from signed archives

Life of this patent

Retaining verifiability of extracted data from signed archives

Life of this patent

Abstract

Claims20