Is it possible to verify a ECDSA based signature in the concordium smart contract ?
The chain does not currently provide primitive operations for smart contracts to verify signatures. However, in principle you can use Rust libraries such as ecdsa in your smart contract for signature verification. In practice, I am unsure how practical this is given the resource constraints of smart contracts. (In particular, I think ECDSA signature verification is fairly computationally intensive, which may not be very practical, since you need to pay for the computation in a smart contract (the “energy”) and even the energy that can be used in a single block is limited.)