Setting up RAW signing for Polymesh token assets

we want to use FireBlocks for PolyMesh blockchain assets ( but I do not see this blockchain in the supported blockchains. So how can i configure my FireBlock account for this blockchain ?

first please genrally describe the way it works with fireblocks, how fireblocks can be used as custodian of non-supported assets like an ERC20 token

I know something about Raw Signing but i have no idea how to configure this and how to utilitze it. I read about enabling this feature but i do not see this in my sandbox dashboard settings menu. So please describe steps how can we configure this using APIs

Hey @shahzad73 PolyMesh is currently not supported in Fireblocks.

However, as you mentioned, you can use RAW signing for managing the private keys for any blockchain that uses ECDSA or EdDSA signature scheme.

You can sign any arbitrary message for any blockchain by providing the full derivation path that you wish to sign with + the signing algorithm.

You can do so by calling our POST /v1/transactions endpoint with the following parameters:

    operation: 'RAW',
    extraParameters: {
        rawMessageData: {
            messages: [ 
                    content: 'the hash of the message to sign',
                    derivationPath: [array of integers] e.g. [44, 60, 0, 0, 0]
            algorithm: 'MPC_ECDSA_SECP256K1' OR 'MPC_ECDSA_SECP256R1' OR 'MPC_EDDSA_ED25519'

Once the message is signed, you can get the signature via the webhook notification we send or by pulling our API for a specific transaction.
Once you have the signature, you can send the signed transaction from your own node infrastructure (or alternatively by using a public node if there is any).

Hope it makes sense.