signTransaction produces huge signature, which fails with 'ECDSA: invalid signature length'

External question — Ethereum Stack Exchange Author: gneric Original post: https://ethereum.stackexchange.com/questions/120176 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. I'm trying to create a transaction (created with populateTransaction ), and sign it offchain (the above result, passed as a parameter to signTransaction ), but it seems it produces an invalid signature (you can see in the logs below), when I send it for ecrecover. // acc1, acc2 should sign the kickout method const acc1UnsignedTx = await vendor .connect(acc1) .populateTransaction.kickout(acc3, tokensToStake); const acc1Wallet = getWalletForIndex(0); const acc1KickoutSignature = await acc1Wallet.signTransaction( acc1UnsignedTx ); // acc 2 const acc2UnsignedTx = await vendor .connect(acc2) .populateTransaction.kickout(acc3, tokensToStake); const acc2Wallet = getWalletForIndex(1); const acc2KickoutSignature = await acc2Wallet.signTransaction( acc2UnsignedTx ); console.log('acc2 unsigned tx ', acc2UnsignedTx) console.log("acc2 signature ", acc2KickoutSignature) // one of them call executeTransaction const nonceBefore = await vendor.nonce(); await vendor.executeMultiSigTx( acc1UnsignedTx.to!, acc1UnsignedTx.value || 0, acc1UnsignedTx.data!, [acc1KickoutSignature, acc2KickoutSignature] ); const getWalletForIndex = (index: any) => { return Wallet.fromMnemonic( 'test test test test test test test test test test test junk', `m/44'/60'/0'/0/${index}` ); }; but I get acc2 unsigned tx { data: '0x512febdc0000000000000000000000003c44cdddb6a900fa2b585dd299e03d12fa4293bc00000000000000000000000000000000000000000000000ad78ebc5ac6200000', to: '0xe7f1725E7734CE288F8367e1Bb143E90bb3F0512', from: '0x70997970C51812dc3A010C7d01b50e0d17dc79C8', gasLimit: BigNumber { _hex: '0x01badbd8', _isBigNumber: true } } acc2 signature 0xf8a680808401badbd894e7f1725e7734ce288f8367e1bb143e90bb3f051280b844512febdc0000000000000000000000003c44cdddb6a900fa2b585dd299e03d12fa4293bc00000000000000000000000000000000000000000000000ad78ebc5ac62000001ca0093579b23a74a1cd1d27956e2673ee70afe46e23792211e324bde43c72ea3a4ca06cd521fc22d17326e22285bcde455041ca83a1253d1f8d381aabfa281d426ed3 1) should kickout through execute when required # of signatures are collected 0 passing (1s) 1 failing 1) Vendor should kickout through execute when required # of signatures are collected: Error: VM Exception while processing transaction: reverted with reason string 'ECDSA: invalid signature length' What am I doing wrong with the creation of the signature ? Why is it such a long string(338 length) ?

External answer — Ethereum Stack Exchange Author: Richard Original post: https://ethereum.stackexchange.com/a/120178 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. The value returned by signTransaction is a RLP-encoded raw Ethereum transaction including the signature. For more info see: https://github.com/ethereum/execution-apis/blob/main/src/eth/sign.json#L28-L46 https://medium.com/@bindassbasanta/sending-a-raw-transaction-ethereum-a7b75f845969