What is the difference or the meaning of these two headers of input scripts?

1) 4730440220 2) 4830450221

I see a lot of them in transactions but I don't understand the difference.


2 Answers 2


Basically it is the length of a signature. In this encoding scheme we find R or S values for sigs, that can have a different length, making the whole string being 72,73 or 74 bytes long.

Pieter described it here: Why the signature is always 65 (1+32+32) bytes long?

and here: What are the parts of a Bitcoin Transaction "Input" script?

I think older tx even had 0x49 at the beginning, then both R and S values would have a length of 33 bytes. I can't find the link, but I was under the impression, that since bitcoin core release 13 these length don't appear anymore (to be verified).

There is also some older reference here: https://bitcointalk.org/index.php?topic=8392.0


For most transactions, the input scriptSig will be a push of the signature followed by a push of the public key. The "push" part is done with script opcodes which say how long it is, and the signature is encoded as DER.

47/48 are the push opcodes, to say 0x47 or 0x48 bytes will follow. Then the signature is encoded as: 0x30 [total-length] 0x02 [R-length] [R] 0x02 [S-length] [S] [sighash-type] So the total length in your examples is either 0x44 or 0x45, and the R-length is 0x20 or 0x21.

  • So they do the same thing in two different ways? If so, why don't use one way?
    – lemanb84
    Commented Jan 25, 2018 at 21:49
  • No, one of them is if the R-length is 0x21 and the other is for R-length 0x20. Depends how long R is in the signature. Commented Jan 25, 2018 at 21:51

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.