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Common Security: CDSA and CSSM, Version 2
Copyright © 1999 The Open Group
Signed Manifests-Requirements
Signed manifests describe the integrity and authenticity of a
collection of digital objects, where the collection is specified as an
acyclic connected graph with an arbitrary number of nodes representing
arbitrary typed digital objects. Digital signaturing based on a public
key infrastructure is the basic integrity mechanism for verifying
manifests.
The following are requirements on the signed manifest:
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Manifest must sit outside the objects being signed
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Manifest must be capable of describing an acyclic graph representing an
arbitrary number of arbitrary typed digital objects including:
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Live objects
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Dynamic objects
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Must be capable of specifying how the object is to be verified.
Check the object's integrity by:
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Reference (URL, pathname, and so on, not the contents of the object)
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Value (only the contents of the object excluding the pathname)
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Reference and value (check both the URL, pathname and the contents)
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Must support one or more unordered signers
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Must support nested signing models.
Objects being signed can themselves be signed objects, such as:
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Signed manifests
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Objects with embedded signatures
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PKCS#7 signed messages
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Each signature must carry an unforgeable credential identifying the signer:
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Digital certificate
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Public key
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Fingerprint
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Must be extensible in the type and format of accepted signer's
credentials (certificate neutral):
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X5.09 certificates
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SDSI certificates
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Signer's credentials can be either:
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Embedded
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Referenced via URL
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Cryptographically neutral with respect to signing algorithms
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Performs complete integrity validation:
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Verify the integrity of the object
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Verify the integrity of the manifest
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Runtime continuous verification for live objects
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Signature format must be based on standards
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Manifest format must be based on standards
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Support emerging standards:
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New signature block formats
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New certificate formats
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use single pass verification of signature(s)
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Verification must be capable of managing progressively rendered
object referents
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