Global proxy with secondary order authentication

[cwgoes]

Goal is to allow easy transferFrom usage without deployment of a second proxy.

• Exchange contract requires known AuthenticatedProxy implementation for semantic correctness of proxy
  • Could add an extra, specially authorised, revised contract which has logic to check transferFrom signatures
  • Need to pass additional data to the proxy contract so that it can authenticate signatures
• Alternative approach: make order maker a contract
  • Use the same proxy contract
  • isValidSignature-equivalent method checks signature on behalf of user
    • Basically checks that the user (looked up from call data) signed the Wyvern order
    • Is there an altered version of EIP 1271 that allows passing extra data?
  • Needs to pass call data as well so user can be looked up
  • Can choose to require additional signature (e.g. by relayer) or not
  • Users then approve proxy deployed by this contract

[cwgoes]

[cwgoes]

Supports interface for contract calls, first try special one, then try EIP 1271 one.