OpenStamp( https://openstamp.io/ ) is a comprehensive service platform for the BTC Stamps ecosystem. We are attempting to integrate the Phantom wallet, but it seems that Phantom currently cannot sign SRC20 transactions. This might be because SRC20 transaction outputs include Bare Multi-Sig outputs. We hope Phantom can support such transactions so that users of the SRC20 ecosystem can effectively use the Phantom wallet. Below is a PSBT containing a Bare Multi-Sig output: psbtBase64 = cHNidP8BAO8CAAAAAf3fctYo7PyLy262lTJjcbZfXf+PqCRHiN8G1HEJaM5tAAAAAAD9// //AyMCAAAAAAAAFgAUSYgc4ve1a2mEBLnS+OqS8KShxo+ZKAAAAAAAACJRIGu93ifnTUKUsRHKlNflgLZFIL/s2nEXvFJJcZ89hiVMHAMAAAAAAABpUSECn1xRsZa4LLhK+Gp0xaMd2r81qJbqkbv9hgSaDk7bj98hAtfbIeeBPG1XWKkFvg929MVdqouJJOZykS/CjzQ87vJlIQICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAlOuAAAAAAABASuTVAAAAAAAACJRIGu93ifnTUKUsRHKlNflgLZFIL/s2nEXvFJJcZ89hiVMARcgw5kZwPX7LlUMooqWqjdRw4TMMrQBJvFI9N0iy88kPioAAAAA { "result": { "tx": { "txid": "026abf33b02b2d6d04478cad907095581ab75d7ed3af4a9ffcc638212a58d8d9", "hash": "026abf33b02b2d6d04478cad907095581ab75d7ed3af4a9ffcc638212a58d8d9", "version": 2, "size": 239, "vsize": 239, "weight": 956, "locktime": 0, "vin": [ { "txid": "6dce680971d406df884724a88fff5d5fb671633295b66ecb8bfcec28d672dffd", "vout": 0, "scriptSig": { "asm": "", "hex": "" }, "sequence": 4294967293 } ], "vout": [ { "value": 0.00000547, "n": 0, "scriptPubKey": { "asm": "0 49881ce2f7b56b698404b9d2f8ea92f0a4a1c68f", "desc": "addr(bc1qfxypechhk44knpqyh8f0365j7zj2r350z4uaqk)#pgfd8gfx", "hex": "001449881ce2f7b56b698404b9d2f8ea92f0a4a1c68f", "address": "bc1qfxypechhk44knpqyh8f0365j7zj2r350z4uaqk", "type": "witness_v0_keyhash" } }, { "value": 0.00010393, "n": 1, "scriptPubKey": { "asm": "1 6bbdde27e74d4294b111ca94d7e580b64520bfecda7117bc5249719f3d86254c", "desc": "rawtr(6bbdde27e74d4294b111ca94d7e580b64520bfecda7117bc5249719f3d86254c)#aszgy9vn", "hex": "51206bbdde27e74d4294b111ca94d7e580b64520bfecda7117bc5249719f3d86254c", "address": "bc1pdw7aufl8f4pffvg3e22d0evqkezjp0lvmfc300zjf9ce70vxy4xqu408zu", "type": "witness_v1_taproot" } }, { "value": 0.00000796, "n": 2, "scriptPubKey": { "asm": "1 029f5c51b196b82cb84af86a74c5a31ddabf35a896ea91bbfd86049a0e4edb8fdf 02d7db21e7813c6d5758a905be0f76f4c55daa8b8924e672912fc28f343ceef265 020202020202020202020202020202020202020202020202020202020202020202 3 OP_CHECKMULTISIG", "desc": "multi(1,029f5c51b196b82cb84af86a74c5a31ddabf35a896ea91bbfd86049a0e4edb8fdf,02d7db21e7813c6d5758a905be0f76f4c55daa8b8924e672912fc28f343ceef265,020202020202020202020202020202020202020202020202020202020202020202)#8us7xp6u", "hex": "5121029f5c51b196b82cb84af86a74c5a31ddabf35a896ea91bbfd86049a0e4edb8fdf2102d7db21e7813c6d5758a905be0f76f4c55daa8b8924e672912fc28f343ceef2652102020202020202020202020202020202020202020202020202020202020202020253ae", "type": "multisig" } } ] }, "global_xpubs": [], "psbt_version": 0, "proprietary": [], "unknown": {}, "inputs": [ { "witness_utxo": { "amount": 0.00021651, "scriptPubKey": { "asm": "1 6bbdde27e74d4294b111ca94d7e580b64520bfecda7117bc5249719f3d86254c", "desc": "rawtr(6bbdde27e74d4294b111ca94d7e580b64520bfecda7117bc5249719f3d86254c)#aszgy9vn", "hex": "51206bbdde27e74d4294b111ca94d7e580b64520bfecda7117bc5249719f3d86254c", "address": "bc1pdw7aufl8f4pffvg3e22d0evqkezjp0lvmfc300zjf9ce70vxy4xqu408zu", "type": "witness_v1_taproot" } }, "taproot_internal_key": "c39919c0f5fb2e550ca28a96aa3751c384cc32b40126f148f4dd22cbcf243e2a" } ], "outputs": [ {}, {}, {} ], "fee": 0.00009915 }, "error": null, "id": null } Here is the code used to sign: await (window as any).phantom.bitcoin.signPSBT(fromHexString(psbtHex), { inputsToSign: [ { address, signingIndexes: [0], } ], }); Then it shows the following error :