RFC6979 nonce (k) generation should be modulo-reduced

[paulmillr]

Currently k256 produces different signatures WHEN msg and privkey are bigger than curve order. This is not a big deal but it's better to follow RFC

See this for more info: bitcoin-core/secp256k1#1064, https://github.com/paulmillr/noble-curves/blob/e0ad0530f64d7cc01514b65d819b7f76db5f0da4/src/abstract/weierstrass.ts#L1047-L1052

[ChALkeR]

I'm not entirely sure I understood this correctly, but if I did, I can't reproduce any difference in behavior:

import * as noble from '@noble/secp256k1'
import elliptic from 'elliptic'

const { ec: EC } = elliptic
const curve = new EC('secp256k1')

// n: fffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364141
const key01 = '0000000000000000000000000000000000000000000000000000000000000001'
const keyn1 = 'fffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364142'
const msg = 'ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff'

const sig0 = await noble.sign(msg, key01)
const sig1 = new Uint8Array(curve.sign(msg, key01).toDER())
const sig2 = new Uint8Array(curve.sign(msg, keyn1).toDER())

console.log({ sig0, sig1, sig2 })
console.log(Buffer.compare(sig0, sig1) ? 'Different' : 'Equal')
console.log(Buffer.compare(sig0, sig2) ? 'Different' : 'Equal')

Output:

{
  sig0: Uint8Array(70) [
     48,  68,   2,  32, 124, 179, 140, 197, 113,  46, 158,  17,
    167, 103,  97,  95,  96, 128, 219, 193,  17, 201, 205, 214,
     19, 235, 152, 153, 159, 217,  42, 134, 186, 253,  69,  64,
      2,  32, 121,  35, 202,  31,  77,   3,  71,  29,  40, 102,
    247, 118, 239, 138, 109,  60, 172,   9, 155,  66, 115,  49,
    174, 178,  69, 170, 157, 175, 237, 220, 241,  21
  ],
  sig1: Uint8Array(70) [
     48,  68,   2,  32, 124, 179, 140, 197, 113,  46, 158,  17,
    167, 103,  97,  95,  96, 128, 219, 193,  17, 201, 205, 214,
     19, 235, 152, 153, 159, 217,  42, 134, 186, 253,  69,  64,
      2,  32, 121,  35, 202,  31,  77,   3,  71,  29,  40, 102,
    247, 118, 239, 138, 109,  60, 172,   9, 155,  66, 115,  49,
    174, 178,  69, 170, 157, 175, 237, 220, 241,  21
  ],
  sig2: Uint8Array(70) [
     48,  68,   2,  32, 124, 179, 140, 197, 113,  46, 158,  17,
    167, 103,  97,  95,  96, 128, 219, 193,  17, 201, 205, 214,
     19, 235, 152, 153, 159, 217,  42, 134, 186, 253,  69,  64,
      2,  32, 121,  35, 202,  31,  77,   3,  71,  29,  40, 102,
    247, 118, 239, 138, 109,  60, 172,   9, 155,  66, 115,  49,
    174, 178,  69, 170, 157, 175, 237, 220, 241,  21
  ]
}
Equal
Equal