content addressing

 content addressing  is a way of looking up pages or files by hashes of their contents rather than the URL of their origin server.

Use in existing web standards
CSP allows specification of hashes eg

Content-Security-Policy: default-src 'self'; script-src 'self' https://example.com 'sha256-base64 encoded hash'

Sub-resource Integrity does too Conformant user agents must support the SHA-256, SHA-384 and SHA-512 cryptographic hash functions for use as part of a request’s integrity metadata and may support additional hash functions. User agents should refuse to support known-weak hashing functions like MD5 or SHA-1 and should restrict supported hashing functions to those known to be collision-resistant.

service worker requests have

Request.integrity Read only Contains the subresource integrity value of the request (e.g., sha256- BpfBw7ivV8q2jLiT13fxDYAe2tJllusRSZ273h2nFSE=).

Proposed new standards
Some discussion at IETF - see this presentation and drafts:


 * https://tools.ietf.org/html/draft-thomson-http-scd
 * https://tools.ietf.org/html/draft-thomson-http-bc
 * https://tools.ietf.org/html/draft-reschke-http-oob-encoding
 * https://tools.ietf.org/html/draft-thomson-http-mice
 * https://tools.ietf.org/html/draft-ietf-httpbis-encryption-encoding

Note the use of this header: x-object-meta-sha1base36: 1d91dx0894wjewukeyxu56os5uhx4ph

Strange de facto standards
HTTP Extensions for a Content-Addressable Web (2001) no longer on the web except as a mailing list archive

Magnet URIs - wikipedia article is more current than the site or draft

Possible integrations
If servers use a prefixed hash in the above format as an ETag, that could enable incremental usage of content hashes.