1

Given an unsigned transaction, constructed using pythereum.transaction, and a signature, created by signing the transaction's hash with a private key, how do I extract the v, r, s values from the signature so they can be added to the unsigned transaction to sign it?

2

The r, s and v values are different slices (in that order) of the signature created by signing a hash value. Refer: https://github.com/ethereumjs/testrpc/pull/19

The ranges of each slice are in the first message of the thread at the above link. Also, note the part about adding 27 to the value of v if v is 0 or 1. The reason for this is an issue whose link is given in that message.

0

If you can use pyethereum to sign with the private key, then Transaction objects already parse out r, s, and v for you. They are made available as attributes of the same name on the transaction object.

In the code for transaction.sign(key), it sets the variables here:

self.v, self.r, self.s = ecsign(rawhash, key)

(But then your transaction object would already be signed, so you wouldn't need to do any more work, and probably don't need r, s, and v anymore.)

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