ecdsa: fix indentation
This commit is contained in:
Daniel Cousens
parent
d05d661aea
commit
087ca551f5
1 changed files with 229 additions and 229 deletions
458
src/ecdsa.js
458
src/ecdsa.js
|
|
@ -4,269 +4,269 @@ var crypto = require('./crypto')
|
|||
var BigInteger = require('bigi')
|
||||
var ECPointFp = require('./ec').ECPointFp
|
||||
|
||||
function deterministicGenerateK(ecparams, hash, D) {
|
||||
assert(Buffer.isBuffer(hash), 'Hash must be a Buffer, not ' + hash)
|
||||
assert.equal(hash.length, 32, 'Hash must be 256 bit')
|
||||
assert(D instanceof BigInteger, 'Private key must be a BigInteger')
|
||||
function deterministicGenerateK(ecparams, hash, D) {
|
||||
assert(Buffer.isBuffer(hash), 'Hash must be a Buffer, not ' + hash)
|
||||
assert.equal(hash.length, 32, 'Hash must be 256 bit')
|
||||
assert(D instanceof BigInteger, 'Private key must be a BigInteger')
|
||||
|
||||
var x = D.toBuffer(32)
|
||||
var k = new Buffer(32)
|
||||
var v = new Buffer(32)
|
||||
k.fill(0)
|
||||
v.fill(1)
|
||||
var x = D.toBuffer(32)
|
||||
var k = new Buffer(32)
|
||||
var v = new Buffer(32)
|
||||
k.fill(0)
|
||||
v.fill(1)
|
||||
|
||||
k = crypto.HmacSHA256(Buffer.concat([v, new Buffer([0]), x, hash]), k)
|
||||
v = crypto.HmacSHA256(v, k)
|
||||
k = crypto.HmacSHA256(Buffer.concat([v, new Buffer([0]), x, hash]), k)
|
||||
v = crypto.HmacSHA256(v, k)
|
||||
|
||||
k = crypto.HmacSHA256(Buffer.concat([v, new Buffer([1]), x, hash]), k)
|
||||
v = crypto.HmacSHA256(v, k)
|
||||
v = crypto.HmacSHA256(v, k)
|
||||
k = crypto.HmacSHA256(Buffer.concat([v, new Buffer([1]), x, hash]), k)
|
||||
v = crypto.HmacSHA256(v, k)
|
||||
v = crypto.HmacSHA256(v, k)
|
||||
|
||||
var n = ecparams.getN()
|
||||
var kB = BigInteger.fromBuffer(v).mod(n)
|
||||
assert(kB.compareTo(BigInteger.ONE) > 0, 'Invalid k value')
|
||||
assert(kB.compareTo(ecparams.getN()) < 0, 'Invalid k value')
|
||||
var n = ecparams.getN()
|
||||
var kB = BigInteger.fromBuffer(v).mod(n)
|
||||
assert(kB.compareTo(BigInteger.ONE) > 0, 'Invalid k value')
|
||||
assert(kB.compareTo(ecparams.getN()) < 0, 'Invalid k value')
|
||||
|
||||
return kB
|
||||
return kB
|
||||
}
|
||||
|
||||
function sign(ecparams, hash, D) {
|
||||
var k = deterministicGenerateK(ecparams, hash, D)
|
||||
|
||||
var n = ecparams.getN()
|
||||
var G = ecparams.getG()
|
||||
var Q = G.multiply(k)
|
||||
var e = BigInteger.fromBuffer(hash)
|
||||
|
||||
var r = Q.getX().toBigInteger().mod(n)
|
||||
assert.notEqual(r.signum(), 0, 'Invalid R value')
|
||||
|
||||
var s = k.modInverse(n).multiply(e.add(D.multiply(r))).mod(n)
|
||||
assert.notEqual(s.signum(), 0, 'Invalid S value')
|
||||
|
||||
var N_OVER_TWO = n.shiftRight(1)
|
||||
|
||||
// enforce low S values, see bip62: 'low s values in signatures'
|
||||
if (s.compareTo(N_OVER_TWO) > 0) {
|
||||
s = n.subtract(s)
|
||||
}
|
||||
|
||||
function sign(ecparams, hash, D) {
|
||||
var k = deterministicGenerateK(ecparams, hash, D)
|
||||
return {r: r, s: s}
|
||||
}
|
||||
|
||||
var n = ecparams.getN()
|
||||
var G = ecparams.getG()
|
||||
var Q = G.multiply(k)
|
||||
var e = BigInteger.fromBuffer(hash)
|
||||
function verify(ecparams, hash, r, s, Q) {
|
||||
var e = BigInteger.fromBuffer(hash)
|
||||
|
||||
var r = Q.getX().toBigInteger().mod(n)
|
||||
assert.notEqual(r.signum(), 0, 'Invalid R value')
|
||||
return verifyRaw(ecparams, e, r, s, Q)
|
||||
}
|
||||
|
||||
var s = k.modInverse(n).multiply(e.add(D.multiply(r))).mod(n)
|
||||
assert.notEqual(s.signum(), 0, 'Invalid S value')
|
||||
function verifyRaw(ecparams, e, r, s, Q) {
|
||||
var n = ecparams.getN()
|
||||
var G = ecparams.getG()
|
||||
|
||||
var N_OVER_TWO = n.shiftRight(1)
|
||||
|
||||
// enforce low S values, see bip62: 'low s values in signatures'
|
||||
if (s.compareTo(N_OVER_TWO) > 0) {
|
||||
s = n.subtract(s)
|
||||
}
|
||||
|
||||
return {r: r, s: s}
|
||||
if (r.compareTo(BigInteger.ONE) < 0 || r.compareTo(n) >= 0) {
|
||||
return false
|
||||
}
|
||||
|
||||
function verify(ecparams, hash, r, s, Q) {
|
||||
var e = BigInteger.fromBuffer(hash)
|
||||
|
||||
return verifyRaw(ecparams, e, r, s, Q)
|
||||
if (s.compareTo(BigInteger.ONE) < 0 || s.compareTo(n) >= 0) {
|
||||
return false
|
||||
}
|
||||
|
||||
function verifyRaw(ecparams, e, r, s, Q) {
|
||||
var n = ecparams.getN()
|
||||
var G = ecparams.getG()
|
||||
var c = s.modInverse(n)
|
||||
var u1 = e.multiply(c).mod(n)
|
||||
var u2 = r.multiply(c).mod(n)
|
||||
|
||||
if (r.compareTo(BigInteger.ONE) < 0 || r.compareTo(n) >= 0) {
|
||||
return false
|
||||
}
|
||||
var point = G.multiplyTwo(u1, Q, u2)
|
||||
var v = point.getX().toBigInteger().mod(n)
|
||||
|
||||
if (s.compareTo(BigInteger.ONE) < 0 || s.compareTo(n) >= 0) {
|
||||
return false
|
||||
}
|
||||
return v.equals(r)
|
||||
}
|
||||
|
||||
var c = s.modInverse(n)
|
||||
var u1 = e.multiply(c).mod(n)
|
||||
var u2 = r.multiply(c).mod(n)
|
||||
/**
|
||||
* Serialize a signature into DER format.
|
||||
*
|
||||
* Takes two BigIntegers representing r and s and returns a byte array.
|
||||
*/
|
||||
function serializeSig(r, s) {
|
||||
var rBa = r.toByteArraySigned()
|
||||
var sBa = s.toByteArraySigned()
|
||||
|
||||
var point = G.multiplyTwo(u1, Q, u2)
|
||||
var v = point.getX().toBigInteger().mod(n)
|
||||
var sequence = []
|
||||
sequence.push(0x02); // INTEGER
|
||||
sequence.push(rBa.length)
|
||||
sequence = sequence.concat(rBa)
|
||||
|
||||
return v.equals(r)
|
||||
sequence.push(0x02); // INTEGER
|
||||
sequence.push(sBa.length)
|
||||
sequence = sequence.concat(sBa)
|
||||
|
||||
sequence.unshift(sequence.length)
|
||||
sequence.unshift(0x30); // SEQUENCE
|
||||
|
||||
return sequence
|
||||
}
|
||||
|
||||
/**
|
||||
* Parses a buffer containing a DER-encoded signature.
|
||||
*
|
||||
* This function will return an object of the form:
|
||||
*
|
||||
* {
|
||||
* r: BigInteger,
|
||||
* s: BigInteger
|
||||
* }
|
||||
*/
|
||||
function parseSig(buffer) {
|
||||
assert.equal(buffer.readUInt8(0), 0x30, 'Not a DER sequence')
|
||||
assert.equal(buffer.readUInt8(1), buffer.length - 2, 'Invalid sequence length')
|
||||
|
||||
assert.equal(buffer.readUInt8(2), 0x02, 'Expected DER integer')
|
||||
var rLen = buffer.readUInt8(3)
|
||||
var rB = buffer.slice(4, 4 + rLen)
|
||||
|
||||
var offset = 4 + rLen
|
||||
assert.equal(buffer.readUInt8(offset), 0x02, 'Expected a 2nd DER integer')
|
||||
var sLen = buffer.readUInt8(1 + offset)
|
||||
var sB = buffer.slice(2 + offset)
|
||||
|
||||
return {
|
||||
r: BigInteger.fromByteArraySigned(rB),
|
||||
s: BigInteger.fromByteArraySigned(sB)
|
||||
}
|
||||
}
|
||||
|
||||
function serializeSigCompact(r, s, i, compressed) {
|
||||
if (compressed) {
|
||||
i += 4
|
||||
}
|
||||
|
||||
/**
|
||||
* Serialize a signature into DER format.
|
||||
*
|
||||
* Takes two BigIntegers representing r and s and returns a byte array.
|
||||
*/
|
||||
function serializeSig(r, s) {
|
||||
var rBa = r.toByteArraySigned()
|
||||
var sBa = s.toByteArraySigned()
|
||||
i += 27
|
||||
|
||||
var sequence = []
|
||||
sequence.push(0x02); // INTEGER
|
||||
sequence.push(rBa.length)
|
||||
sequence = sequence.concat(rBa)
|
||||
var buffer = new Buffer(65)
|
||||
buffer.writeUInt8(i, 0)
|
||||
r.toBuffer(32).copy(buffer, 1)
|
||||
s.toBuffer(32).copy(buffer, 33)
|
||||
|
||||
sequence.push(0x02); // INTEGER
|
||||
sequence.push(sBa.length)
|
||||
sequence = sequence.concat(sBa)
|
||||
return buffer
|
||||
}
|
||||
|
||||
sequence.unshift(sequence.length)
|
||||
sequence.unshift(0x30); // SEQUENCE
|
||||
function parseSigCompact(buffer) {
|
||||
assert.equal(buffer.length, 65, 'Invalid signature length')
|
||||
var i = buffer.readUInt8(0) - 27
|
||||
|
||||
return sequence
|
||||
// At most 3 bits
|
||||
assert.equal(i, i & 7, 'Invalid signature type')
|
||||
var compressed = !!(i & 4)
|
||||
|
||||
// Recovery param only
|
||||
i = i & 3
|
||||
|
||||
var r = BigInteger.fromBuffer(buffer.slice(1, 33))
|
||||
var s = BigInteger.fromBuffer(buffer.slice(33))
|
||||
|
||||
return {
|
||||
r: r,
|
||||
s: s,
|
||||
i: i,
|
||||
compressed: compressed
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* 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(ecparams, e, r, s, i) {
|
||||
assert.strictEqual(i & 3, i, 'The recovery param is more than two bits')
|
||||
|
||||
// A set LSB signifies that the y-coordinate is odd
|
||||
// By reduction, the y-coordinate is even if it is clear
|
||||
var isYEven = !(i & 1)
|
||||
|
||||
// The more significant bit specifies whether we should use the
|
||||
// first or second candidate key.
|
||||
var isSecondKey = i >> 1
|
||||
|
||||
var n = ecparams.getN()
|
||||
var G = ecparams.getG()
|
||||
var curve = ecparams.getCurve()
|
||||
var p = curve.getQ()
|
||||
var a = curve.getA().toBigInteger()
|
||||
var b = curve.getB().toBigInteger()
|
||||
|
||||
// We precalculate (p + 1) / 4 where p is the field order
|
||||
if (!curve.P_OVER_FOUR) {
|
||||
curve.P_OVER_FOUR = p.add(BigInteger.ONE).shiftRight(2)
|
||||
}
|
||||
|
||||
/**
|
||||
* Parses a buffer containing a DER-encoded signature.
|
||||
*
|
||||
* This function will return an object of the form:
|
||||
*
|
||||
* {
|
||||
* r: BigInteger,
|
||||
* s: BigInteger
|
||||
* }
|
||||
*/
|
||||
function parseSig(buffer) {
|
||||
assert.equal(buffer.readUInt8(0), 0x30, 'Not a DER sequence')
|
||||
assert.equal(buffer.readUInt8(1), buffer.length - 2, 'Invalid sequence length')
|
||||
// 1.1 Compute x
|
||||
var x = isSecondKey ? r.add(n) : r
|
||||
|
||||
assert.equal(buffer.readUInt8(2), 0x02, 'Expected DER integer')
|
||||
var rLen = buffer.readUInt8(3)
|
||||
var rB = buffer.slice(4, 4 + rLen)
|
||||
// 1.3 Convert x to point
|
||||
var alpha = x.pow(3).add(a.multiply(x)).add(b).mod(p)
|
||||
var beta = alpha.modPow(curve.P_OVER_FOUR, p)
|
||||
|
||||
var offset = 4 + rLen
|
||||
assert.equal(buffer.readUInt8(offset), 0x02, 'Expected a 2nd DER integer')
|
||||
var sLen = buffer.readUInt8(1 + offset)
|
||||
var sB = buffer.slice(2 + offset)
|
||||
// If beta is even, but y isn't, or vice versa, then convert it,
|
||||
// otherwise we're done and y == beta.
|
||||
var y = (beta.isEven() ^ isYEven) ? p.subtract(beta) : beta
|
||||
|
||||
return {
|
||||
r: BigInteger.fromByteArraySigned(rB),
|
||||
s: BigInteger.fromByteArraySigned(sB)
|
||||
// 1.4 Check that nR isn't at infinity
|
||||
var R = new ECPointFp(curve, curve.fromBigInteger(x), curve.fromBigInteger(y))
|
||||
R.validate()
|
||||
|
||||
// 1.5 Compute -e from e
|
||||
var eNeg = e.negate().mod(n)
|
||||
|
||||
// 1.6 Compute Q = r^-1 (sR - eG)
|
||||
// Q = r^-1 (sR + -eG)
|
||||
var rInv = r.modInverse(n)
|
||||
|
||||
var Q = R.multiplyTwo(s, G, eNeg).multiply(rInv)
|
||||
Q.validate()
|
||||
|
||||
if (!verifyRaw(ecparams, e, r, s, Q)) {
|
||||
throw new Error("Pubkey recovery unsuccessful")
|
||||
}
|
||||
|
||||
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(ecparams, e, r, s, Q) {
|
||||
for (var i = 0; i < 4; i++) {
|
||||
var Qprime = recoverPubKey(ecparams, e, r, s, i)
|
||||
|
||||
if (Qprime.equals(Q)) {
|
||||
return i
|
||||
}
|
||||
}
|
||||
|
||||
function serializeSigCompact(r, s, i, compressed) {
|
||||
if (compressed) {
|
||||
i += 4
|
||||
}
|
||||
|
||||
i += 27
|
||||
|
||||
var buffer = new Buffer(65)
|
||||
buffer.writeUInt8(i, 0)
|
||||
r.toBuffer(32).copy(buffer, 1)
|
||||
s.toBuffer(32).copy(buffer, 33)
|
||||
|
||||
return buffer
|
||||
}
|
||||
|
||||
function parseSigCompact(buffer) {
|
||||
assert.equal(buffer.length, 65, 'Invalid signature length')
|
||||
var i = buffer.readUInt8(0) - 27
|
||||
|
||||
// At most 3 bits
|
||||
assert.equal(i, i & 7, 'Invalid signature type')
|
||||
var compressed = !!(i & 4)
|
||||
|
||||
// Recovery param only
|
||||
i = i & 3
|
||||
|
||||
var r = BigInteger.fromBuffer(buffer.slice(1, 33))
|
||||
var s = BigInteger.fromBuffer(buffer.slice(33))
|
||||
|
||||
return {
|
||||
r: r,
|
||||
s: s,
|
||||
i: i,
|
||||
compressed: compressed
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* 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(ecparams, e, r, s, i) {
|
||||
assert.strictEqual(i & 3, i, 'The recovery param is more than two bits')
|
||||
|
||||
// A set LSB signifies that the y-coordinate is odd
|
||||
// By reduction, the y-coordinate is even if it is clear
|
||||
var isYEven = !(i & 1)
|
||||
|
||||
// The more significant bit specifies whether we should use the
|
||||
// first or second candidate key.
|
||||
var isSecondKey = i >> 1
|
||||
|
||||
var n = ecparams.getN()
|
||||
var G = ecparams.getG()
|
||||
var curve = ecparams.getCurve()
|
||||
var p = curve.getQ()
|
||||
var a = curve.getA().toBigInteger()
|
||||
var b = curve.getB().toBigInteger()
|
||||
|
||||
// We precalculate (p + 1) / 4 where p is the field order
|
||||
if (!curve.P_OVER_FOUR) {
|
||||
curve.P_OVER_FOUR = p.add(BigInteger.ONE).shiftRight(2)
|
||||
}
|
||||
|
||||
// 1.1 Compute x
|
||||
var x = isSecondKey ? r.add(n) : r
|
||||
|
||||
// 1.3 Convert x to point
|
||||
var alpha = x.pow(3).add(a.multiply(x)).add(b).mod(p)
|
||||
var beta = alpha.modPow(curve.P_OVER_FOUR, p)
|
||||
|
||||
// If beta is even, but y isn't, or vice versa, then convert it,
|
||||
// otherwise we're done and y == beta.
|
||||
var y = (beta.isEven() ^ isYEven) ? p.subtract(beta) : beta
|
||||
|
||||
// 1.4 Check that nR isn't at infinity
|
||||
var R = new ECPointFp(curve, curve.fromBigInteger(x), curve.fromBigInteger(y))
|
||||
R.validate()
|
||||
|
||||
// 1.5 Compute -e from e
|
||||
var eNeg = e.negate().mod(n)
|
||||
|
||||
// 1.6 Compute Q = r^-1 (sR - eG)
|
||||
// Q = r^-1 (sR + -eG)
|
||||
var rInv = r.modInverse(n)
|
||||
|
||||
var Q = R.multiplyTwo(s, G, eNeg).multiply(rInv)
|
||||
Q.validate()
|
||||
|
||||
if (!verifyRaw(ecparams, e, r, s, Q)) {
|
||||
throw new Error("Pubkey recovery unsuccessful")
|
||||
}
|
||||
|
||||
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(ecparams, e, r, s, Q) {
|
||||
for (var i = 0; i < 4; i++) {
|
||||
var Qprime = recoverPubKey(ecparams, e, r, s, i)
|
||||
|
||||
if (Qprime.equals(Q)) {
|
||||
return i
|
||||
}
|
||||
}
|
||||
|
||||
throw new Error('Unable to find valid recovery factor')
|
||||
}
|
||||
throw new Error('Unable to find valid recovery factor')
|
||||
}
|
||||
|
||||
module.exports = {
|
||||
calcPubKeyRecoveryParam: calcPubKeyRecoveryParam,
|
||||
deterministicGenerateK: deterministicGenerateK,
|
||||
recoverPubKey: recoverPubKey,
|
||||
sign: sign,
|
||||
verify: verify,
|
||||
verifyRaw: verifyRaw,
|
||||
serializeSig: serializeSig,
|
||||
parseSig: parseSig,
|
||||
serializeSigCompact: serializeSigCompact,
|
||||
parseSigCompact: parseSigCompact
|
||||
calcPubKeyRecoveryParam: calcPubKeyRecoveryParam,
|
||||
deterministicGenerateK: deterministicGenerateK,
|
||||
recoverPubKey: recoverPubKey,
|
||||
sign: sign,
|
||||
verify: verify,
|
||||
verifyRaw: verifyRaw,
|
||||
serializeSig: serializeSig,
|
||||
parseSig: parseSig,
|
||||
serializeSigCompact: serializeSigCompact,
|
||||
parseSigCompact: parseSigCompact
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in a new issue