what is the process to transform the noble-secp256k1 signature output to a node:crypto signature?

[lemoustachiste]

Hi,

so I'm trying to use @noble/secp256k1 as a replacement/polyfill for the node:crypto (and crypto.subtle) methods to sign and verify.

However the output of both sign methods are different.

Noble yields the low-level r + s signature as such:

Signature {
  r: 30673915999826815067112358723830053709740609731848351883723761154187753271507n,
  s: 27924747462559541784234137714889274701124087642782423432899060127035916103299n,
  recovery: 1
}

And the crypto/webcrypto world returns a Buffer as follows:

ArrayBuffer {
  [Uint8Contents]: <26 af be f2 d1 9b 09 fb be 20 3b ce ca 09 33 f4 c5 ed c5 24 ae 77 b7 fc 5c 4b 69 7d bd c6 a5 aa a1 12 9f 07 ca a8 62 9d 5b bd 6a b4 c0 a2 70 9d b0 f2 5f ea ce f2 b9 b4 91 d5 17 de 8f d6 88 b6>,
  byteLength: 64
}

I don't know how to transform (and the inverse) the noble signature to be following the same format as the crypto one. Can you point me in the right direction?

Thanks

[paulmillr]

use Signature#toCompactRawBytes

[lemoustachiste]

Perfect, thanks for the swift answer