I've been searching for a way to create blind ECDSA signatures. My research and experimentation has led me to believe that this is not possible.
I've been attempting to articulate why and I think that it is because it is not possible to apply a transformation to the message in a way which can be reversed whilst retaining a valid signature. The message and signature cannot be transformed as required because the ephemeral key is not known by the recipient, and if the key were known then the long term signing key could be determined. An ECDSA signature only permits validating that the signature was formed from the message and the private key corresponding to the expected public key.
I would like to confirm whether there are any known ECDSA blind signature schemes? I suppose publication bias might prevent this from appearing in the literature.
More generally are there any known ECDSA variants such as proxy signatures? My research has led me to the conclusion that it's functionality is entirely constrained to yielding a standard signature scheme.