ecdsa: remove unused functions

src/ecdsa.js

@@ -154,93 +154,8 @@ function verify (hash, signature, Q) {
   return v.equals(r)
 }
 
-/**
-  * Recover a public key from a signature.
-  *
-  * See SEC 1: Elliptic Curve Cryptography, section 4.1.6, "Public
-  * Key Recovery Operation".
-  *
-  * http://www.secg.org/download/aid-780/sec1-v2.pdf
-  */
-function recoverPubKey (e, signature, i) {
-  typeforce(types.tuple(
-    types.BigInt,
-    types.ECSignature,
-    types.UInt2
-  ), arguments)
-
-  var n = secp256k1.n
-  var G = secp256k1.G
-  var r = signature.r
-  var s = signature.s
-
-  if (r.signum() <= 0 || r.compareTo(n) >= 0) throw new Error('Invalid r value')
-  if (s.signum() <= 0 || s.compareTo(n) >= 0) throw new Error('Invalid s value')
-
-  // A set LSB signifies that the y-coordinate is odd
-  var isYOdd = i & 1
-
-  // The more significant bit specifies whether we should use the
-  // first or second candidate key.
-  var isSecondKey = i >> 1
-
-  // 1.1 Let x = r + jn
-  var x = isSecondKey ? r.add(n) : r
-  var R = secp256k1.pointFromX(isYOdd, x)
-
-  // 1.4 Check that nR is at infinity
-  var nR = R.multiply(n)
-  if (!secp256k1.isInfinity(nR)) throw new Error('nR is not a valid curve point')
-
-  // Compute r^-1
-  var rInv = r.modInverse(n)
-
-  // Compute -e from e
-  var eNeg = e.negate().mod(n)
-
-  // 1.6.1 Compute Q = r^-1 (sR -  eG)
-  //               Q = r^-1 (sR + -eG)
-  var Q = R.multiplyTwo(s, G, eNeg).multiply(rInv)
-
-  secp256k1.validate(Q)
-
-  return Q
-}
-
-/**
-  * Calculate pubkey extraction parameter.
-  *
-  * When extracting a pubkey from a signature, we have to
-  * distinguish four different cases. Rather than putting this
-  * burden on the verifier, Bitcoin includes a 2-bit value with the
-  * signature.
-  *
-  * This function simply tries all four cases and returns the value
-  * that resulted in a successful pubkey recovery.
-  */
-function calcPubKeyRecoveryParam (e, signature, Q) {
-  typeforce(types.tuple(
-    types.BigInt,
-    types.ECSignature,
-    types.ECPoint
-  ), arguments)
-
-  for (var i = 0; i < 4; i++) {
-    var Qprime = recoverPubKey(e, signature, i)
-
-    // 1.6.2 Verify Q
-    if (Qprime.equals(Q)) {
-      return i
-    }
-  }
-
-  throw new Error('Unable to find valid recovery factor')
-}
-
 module.exports = {
-  calcPubKeyRecoveryParam: calcPubKeyRecoveryParam,
   deterministicGenerateK: deterministicGenerateK,
-  recoverPubKey: recoverPubKey,
   sign: sign,
   verify: verify,