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+# RFC 208: additional crypto and CBOR libraries
+
+## Summary
+
+Several new web APIs require additional cryptography and CBOR libraries to
+properly test, for example the [Protected Audience Additional Bids feature](https://github.com/WICG/turtledove/blob/main/FLEDGE.md#623-additional-bid-keys )
+uses Ed25519 signatures, the [Protected Audience Key-Value services](https://github.com/WICG/turtledove/blob/main/FLEDGE_Key_Value_Server_API.md#query-api-version-2) and
+[Bidding and Auction services](https://github.com/WICG/turtledove/blob/main/FLEDGE_browser_bidding_and_auction_API.md) use CBOR data encoding and HPKE encryption.
+These additional libraries are to support cryptography and the CBOR
+protocols not otherwise supported in JavaScript or Python, namely Ed25519,
+HPKE, and CBOR. There are open source libraries commonly available that
+implement these protocols and have compatible licenses. This RFC proposes
+adding such libraries to the tools/ directory (for the Python library) and
+to a [<spec>/third_party/ directory (for the JavaScript libraries)](https://github.com/web-platform-tests/rfcs/issues/46#issuecomment-587707539) so
+that web-platform-tests may exercise and verify proper compatible
+implementations of these new web APIs.
+
+## Details
+
+### We're proposing adding these Python libraries to the tools/ directory:
+
+These are all self-contained (no dependencies) pure-python libraries.
+
+##### An HPKE Python implementation:
+https://github.com/dajiaji/pyhpke
+
+This HPKE library is intended to be used by test code running on wptserve
+that may receive an HPKE encrypted message and have to decrypt it and encrypt
+a response.  This library is MIT licensed.
+
+##### A CBOR Python implementation:
+https://github.com/agronholm/cbor2
+
+This CBOR library is intended to be used by test code running on wptserve that
+may receive an CBOR encoded message and have to decode it and encode a response.
+This library is MIT licensed.
+
+### We're proposing adding these JavaScript libraries to a third_party/ subdirectory under our spec directory as per [this advice](https://github.com/web-platform-tests/rfcs/issues/46#issuecomment-587707539):
+
+These HPKE and CBOR libraries are used by test code to decrypt and decode data
+coming from JavaScript APIs to verify their contents, and used by test code to
+encode and encrypt response data.  These libraries and all of their included
+dependencies are MIT licensed.
+
+##### An HPKE JavaScript implementation:
+https://github.com/dajiaji/hpke-js
+
+This library has some dependencies, so we're proposing building/transpiling into a single hpke.js file.
+This library is MIT licensed.
+
+##### A CBOR JavaScript implementation:
+https://github.com/paroga/cbor-js/blob/master/cbor.js
+
+This library is MIT licensed.
+
+##### An Ed25519 JavaScript implementation:
+https://github.com/paulmillr/noble-ed25519
+
+This Ed25519 library is intended to be used by JavaScript test code
+that may receive an Ed25519 private key and message to sign that message, or
+a public key and signature to verify that signature.  This library is MIT licensed.
+
+## Risks
+
+Users of these libraries may need to update them from time to time if new
+functionality or fixes are required. This is likely not a big risk.
+
+The HPKE library, once built/transpiled into one JavaScript file, may be slightly harder to debug, but we'll disable minification when building.