[Ethereum] a “raw transaction” and what is it used for

raw-transaction

I come across a lot of posts on Ethereum Stack Exchange about "raw transactions" (more than 45 posts have this tag at the moment), but I don't really understand what it is. I have searched both Stack Exchange and the web and can't find a 101 explanation, with the exception of this one post where in answer to a question about the difference between raw transactions and other transactions, "eth" defined a raw transaction as "a transaction in raw bytes." Being new to both computing and the blockchain world, that did not clarify all that much for me, and still left me wondering: What is a transaction "in raw bytes"? And what are they useful for? Most posts seem to be focused on how to generate or sign a raw transaction, get a raw transaction from Hash, parse one etc. I'd love to understand what it actually is and what it enables.

Best Answer

A transaction as defined in the Yellow Paper section 4.3 it consist of several fields (like gasPrice, value, etc). To store them in the blockchain they are encoded using the Recursive Length Prefix algorithm into a sequence of bytes. This sequence is called a raw transaction.

Basically a raw transaction is a machine representation of a transaction, with the signature attached to it.

Related Solutions

[Ethereum] How to get signature parameters from a transaction

In the transaction object returned by eth_getTransaction to my geth instance does include the ECDSA parameters:

curl -X POST --data '{"jsonrpc":"2.0","method":"eth_getTransactionByHash","params": ["0x47ced780ecca7c273243dded62c6a240f3ba4332ab067345909a304d7294cfda"],"id":1}' localhost:8545

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "blockHash": "0x7126318b5736f655049fcb7c3f6ef02d0986a5553cb1b1fbc0ca188543b1e60a",
    "blockNumber": "0x339d04",
    "from": "0xea674fdde714fd979de3edf0f56aa9716b898ec8",
    "gas": "0x15f90",
    "gasPrice": "0x4a817c800",
    "hash": "0x47ced780ecca7c273243dded62c6a240f3ba4332ab067345909a304d7294cfda",
    "input": "0x",
    "nonce": "0x15dcf8",
    "to": "0xf34a762291e2578b79646cbf296abf4f5a242b3d",
    "transactionIndex": "0x0",
    "value": "0x16978c7c04171dc",
    "v": "0x26",
    "r": "0xe448b291661c63d8add23a8be2eb726e92ace5c100e902ee75a6396f8df8d221",
    "s": "0x197fb2e88dc2d4e8f606faf6abdb8012d21b024939756ceaf2d39b4bef619fa4"
  }
}

Note the v, r, and s parameters: these are what you need to verify the signature. I'm not sure why these aren't in the official RPC spec, but they are available if you need them

[Ethereum] Raw transaction structure

You may want to try using the "unsign()" function in the ethereumjs-tx-sign library to inspect all the data contained in each of your raw transaction values.. and compare the contents.

You may find that it comes down to fixing an oversight in properly encoding all of the input parameters used when generating the raw transaction. A missing '0x' can wreak havoc.

Best Answer

Related Solutions

[Ethereum] How to get signature parameters from a transaction

[Ethereum] Raw transaction structure

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