btcec_test.go raw

   1  // Copyright 2011 The Go Authors. All rights reserved.
   2  // Copyright 2011 ThePiachu. All rights reserved.
   3  // Copyright 2013-2016 The btcsuite developers
   4  // Use of this source code is governed by an ISC
   5  // license that can be found in the LICENSE file.
   6  
   7  package ecc
   8  
   9  import (
  10  	"crypto/rand"
  11  	"fmt"
  12  	"math/big"
  13  	"testing"
  14  )
  15  
  16  // isJacobianOnS256Curve returns boolean if the point (x,y,z) is on the
  17  // secp256k1 curve.
  18  func isJacobianOnS256Curve(x, y, z *fieldVal) bool {
  19  	// Elliptic curve equation for secp256k1 is: y^2 = x^3 + 7
  20  	// In Jacobian coordinates, Y = y/z^3 and X = x/z^2
  21  	// Thus:
  22  	// (y/z^3)^2 = (x/z^2)^3 + 7
  23  	// y^2/z^6 = x^3/z^6 + 7
  24  	// y^2 = x^3 + 7*z^6
  25  	var y2, z2, x3, result fieldVal
  26  	y2.SquareVal(y).Normalize()
  27  	z2.SquareVal(z)
  28  	x3.SquareVal(x).Mul(x)
  29  	result.SquareVal(&z2).Mul(&z2).MulInt(7).Add(&x3).Normalize()
  30  	return y2.Equals(&result)
  31  }
  32  
  33  // TestAddJacobian tests addition of points projected in Jacobian coordinates.
  34  func TestAddJacobian(t *testing.T) {
  35  	tests := []struct {
  36  		x1, y1, z1 string // Coordinates (in hex) of first point to add
  37  		x2, y2, z2 string // Coordinates (in hex) of second point to add
  38  		x3, y3, z3 string // Coordinates (in hex) of expected point
  39  	}{
  40  		// Addition with a point at infinity (left hand side).
  41  		// ∞ + P = P
  42  		{
  43  			"0",
  44  			"0",
  45  			"0",
  46  			"d74bf844b0862475103d96a611cf2d898447e288d34b360bc885cb8ce7c00575",
  47  			"131c670d414c4546b88ac3ff664611b1c38ceb1c21d76369d7a7a0969d61d97d",
  48  			"1",
  49  			"d74bf844b0862475103d96a611cf2d898447e288d34b360bc885cb8ce7c00575",
  50  			"131c670d414c4546b88ac3ff664611b1c38ceb1c21d76369d7a7a0969d61d97d",
  51  			"1",
  52  		},
  53  		// Addition with a point at infinity (right hand side).
  54  		// P + ∞ = P
  55  		{
  56  			"d74bf844b0862475103d96a611cf2d898447e288d34b360bc885cb8ce7c00575",
  57  			"131c670d414c4546b88ac3ff664611b1c38ceb1c21d76369d7a7a0969d61d97d",
  58  			"1",
  59  			"0",
  60  			"0",
  61  			"0",
  62  			"d74bf844b0862475103d96a611cf2d898447e288d34b360bc885cb8ce7c00575",
  63  			"131c670d414c4546b88ac3ff664611b1c38ceb1c21d76369d7a7a0969d61d97d",
  64  			"1",
  65  		},
  66  		// Addition with z1=z2=1 different x values.
  67  		{
  68  			"34f9460f0e4f08393d192b3c5133a6ba099aa0ad9fd54ebccfacdfa239ff49c6",
  69  			"0b71ea9bd730fd8923f6d25a7a91e7dd7728a960686cb5a901bb419e0f2ca232",
  70  			"1",
  71  			"d74bf844b0862475103d96a611cf2d898447e288d34b360bc885cb8ce7c00575",
  72  			"131c670d414c4546b88ac3ff664611b1c38ceb1c21d76369d7a7a0969d61d97d",
  73  			"1",
  74  			"0cfbc7da1e569b334460788faae0286e68b3af7379d5504efc25e4dba16e46a6",
  75  			"e205f79361bbe0346b037b4010985dbf4f9e1e955e7d0d14aca876bfa79aad87",
  76  			"44a5646b446e3877a648d6d381370d9ef55a83b666ebce9df1b1d7d65b817b2f",
  77  		},
  78  		// Addition with z1=z2=1 same x opposite y.
  79  		// P(x, y, z) + P(x, -y, z) = infinity
  80  		{
  81  			"34f9460f0e4f08393d192b3c5133a6ba099aa0ad9fd54ebccfacdfa239ff49c6",
  82  			"0b71ea9bd730fd8923f6d25a7a91e7dd7728a960686cb5a901bb419e0f2ca232",
  83  			"1",
  84  			"34f9460f0e4f08393d192b3c5133a6ba099aa0ad9fd54ebccfacdfa239ff49c6",
  85  			"f48e156428cf0276dc092da5856e182288d7569f97934a56fe44be60f0d359fd",
  86  			"1",
  87  			"0",
  88  			"0",
  89  			"0",
  90  		},
  91  		// Addition with z1=z2=1 same point.
  92  		// P(x, y, z) + P(x, y, z) = 2P
  93  		{
  94  			"34f9460f0e4f08393d192b3c5133a6ba099aa0ad9fd54ebccfacdfa239ff49c6",
  95  			"0b71ea9bd730fd8923f6d25a7a91e7dd7728a960686cb5a901bb419e0f2ca232",
  96  			"1",
  97  			"34f9460f0e4f08393d192b3c5133a6ba099aa0ad9fd54ebccfacdfa239ff49c6",
  98  			"0b71ea9bd730fd8923f6d25a7a91e7dd7728a960686cb5a901bb419e0f2ca232",
  99  			"1",
 100  			"ec9f153b13ee7bd915882859635ea9730bf0dc7611b2c7b0e37ee64f87c50c27",
 101  			"b082b53702c466dcf6e984a35671756c506c67c2fcb8adb408c44dd0755c8f2a",
 102  			"16e3d537ae61fb1247eda4b4f523cfbaee5152c0d0d96b520376833c1e594464",
 103  		},
 104  
 105  		// Addition with z1=z2 (!=1) different x values.
 106  		{
 107  			"d3e5183c393c20e4f464acf144ce9ae8266a82b67f553af33eb37e88e7fd2718",
 108  			"5b8f54deb987ec491fb692d3d48f3eebb9454b034365ad480dda0cf079651190",
 109  			"2",
 110  			"5d2fe112c21891d440f65a98473cb626111f8a234d2cd82f22172e369f002147",
 111  			"98e3386a0a622a35c4561ffb32308d8e1c6758e10ebb1b4ebd3d04b4eb0ecbe8",
 112  			"2",
 113  			"cfbc7da1e569b334460788faae0286e68b3af7379d5504efc25e4dba16e46a60",
 114  			"817de4d86ef80d1ac0ded00426176fd3e787a5579f43452b2a1db021e6ac3778",
 115  			"129591ad11b8e1de99235b4e04dc367bd56a0ed99baf3a77c6c75f5a6e05f08d",
 116  		},
 117  		// Addition with z1=z2 (!=1) same x opposite y.
 118  		// P(x, y, z) + P(x, -y, z) = infinity
 119  		{
 120  			"d3e5183c393c20e4f464acf144ce9ae8266a82b67f553af33eb37e88e7fd2718",
 121  			"5b8f54deb987ec491fb692d3d48f3eebb9454b034365ad480dda0cf079651190",
 122  			"2",
 123  			"d3e5183c393c20e4f464acf144ce9ae8266a82b67f553af33eb37e88e7fd2718",
 124  			"a470ab21467813b6e0496d2c2b70c11446bab4fcbc9a52b7f225f30e869aea9f",
 125  			"2",
 126  			"0",
 127  			"0",
 128  			"0",
 129  		},
 130  		// Addition with z1=z2 (!=1) same point.
 131  		// P(x, y, z) + P(x, y, z) = 2P
 132  		{
 133  			"d3e5183c393c20e4f464acf144ce9ae8266a82b67f553af33eb37e88e7fd2718",
 134  			"5b8f54deb987ec491fb692d3d48f3eebb9454b034365ad480dda0cf079651190",
 135  			"2",
 136  			"d3e5183c393c20e4f464acf144ce9ae8266a82b67f553af33eb37e88e7fd2718",
 137  			"5b8f54deb987ec491fb692d3d48f3eebb9454b034365ad480dda0cf079651190",
 138  			"2",
 139  			"9f153b13ee7bd915882859635ea9730bf0dc7611b2c7b0e37ee65073c50fabac",
 140  			"2b53702c466dcf6e984a35671756c506c67c2fcb8adb408c44dd125dc91cb988",
 141  			"6e3d537ae61fb1247eda4b4f523cfbaee5152c0d0d96b520376833c2e5944a11",
 142  		},
 143  
 144  		// Addition with z1!=z2 and z2=1 different x values.
 145  		{
 146  			"d3e5183c393c20e4f464acf144ce9ae8266a82b67f553af33eb37e88e7fd2718",
 147  			"5b8f54deb987ec491fb692d3d48f3eebb9454b034365ad480dda0cf079651190",
 148  			"2",
 149  			"d74bf844b0862475103d96a611cf2d898447e288d34b360bc885cb8ce7c00575",
 150  			"131c670d414c4546b88ac3ff664611b1c38ceb1c21d76369d7a7a0969d61d97d",
 151  			"1",
 152  			"3ef1f68795a6ccd1181e23eab80a1b9a2cebdcde755413bf097936eb5b91b4f3",
 153  			"0bef26c377c068d606f6802130bb7e9f3c3d2abcfa1a295950ed81133561cb04",
 154  			"252b235a2371c3bd3246b69c09b86cf7aad41db3375e74ef8d8ebeb4dc0be11a",
 155  		},
 156  		// Addition with z1!=z2 and z2=1 same x opposite y.
 157  		// P(x, y, z) + P(x, -y, z) = infinity
 158  		{
 159  			"d3e5183c393c20e4f464acf144ce9ae8266a82b67f553af33eb37e88e7fd2718",
 160  			"5b8f54deb987ec491fb692d3d48f3eebb9454b034365ad480dda0cf079651190",
 161  			"2",
 162  			"34f9460f0e4f08393d192b3c5133a6ba099aa0ad9fd54ebccfacdfa239ff49c6",
 163  			"f48e156428cf0276dc092da5856e182288d7569f97934a56fe44be60f0d359fd",
 164  			"1",
 165  			"0",
 166  			"0",
 167  			"0",
 168  		},
 169  		// Addition with z1!=z2 and z2=1 same point.
 170  		// P(x, y, z) + P(x, y, z) = 2P
 171  		{
 172  			"d3e5183c393c20e4f464acf144ce9ae8266a82b67f553af33eb37e88e7fd2718",
 173  			"5b8f54deb987ec491fb692d3d48f3eebb9454b034365ad480dda0cf079651190",
 174  			"2",
 175  			"34f9460f0e4f08393d192b3c5133a6ba099aa0ad9fd54ebccfacdfa239ff49c6",
 176  			"0b71ea9bd730fd8923f6d25a7a91e7dd7728a960686cb5a901bb419e0f2ca232",
 177  			"1",
 178  			"9f153b13ee7bd915882859635ea9730bf0dc7611b2c7b0e37ee65073c50fabac",
 179  			"2b53702c466dcf6e984a35671756c506c67c2fcb8adb408c44dd125dc91cb988",
 180  			"6e3d537ae61fb1247eda4b4f523cfbaee5152c0d0d96b520376833c2e5944a11",
 181  		},
 182  
 183  		// Addition with z1!=z2 and z2!=1 different x values.
 184  		// P(x, y, z) + P(x, y, z) = 2P
 185  		{
 186  			"d3e5183c393c20e4f464acf144ce9ae8266a82b67f553af33eb37e88e7fd2718",
 187  			"5b8f54deb987ec491fb692d3d48f3eebb9454b034365ad480dda0cf079651190",
 188  			"2",
 189  			"91abba6a34b7481d922a4bd6a04899d5a686f6cf6da4e66a0cb427fb25c04bd4",
 190  			"03fede65e30b4e7576a2abefc963ddbf9fdccbf791b77c29beadefe49951f7d1",
 191  			"3",
 192  			"3f07081927fd3f6dadd4476614c89a09eba7f57c1c6c3b01fa2d64eac1eef31e",
 193  			"949166e04ebc7fd95a9d77e5dfd88d1492ecffd189792e3944eb2b765e09e031",
 194  			"eb8cba81bcffa4f44d75427506737e1f045f21e6d6f65543ee0e1d163540c931",
 195  		}, // Addition with z1!=z2 and z2!=1 same x opposite y.
 196  		// P(x, y, z) + P(x, -y, z) = infinity
 197  		{
 198  			"d3e5183c393c20e4f464acf144ce9ae8266a82b67f553af33eb37e88e7fd2718",
 199  			"5b8f54deb987ec491fb692d3d48f3eebb9454b034365ad480dda0cf079651190",
 200  			"2",
 201  			"dcc3768780c74a0325e2851edad0dc8a566fa61a9e7fc4a34d13dcb509f99bc7",
 202  			"cafc41904dd5428934f7d075129c8ba46eb622d4fc88d72cd1401452664add18",
 203  			"3",
 204  			"0",
 205  			"0",
 206  			"0",
 207  		},
 208  		// Addition with z1!=z2 and z2!=1 same point.
 209  		// P(x, y, z) + P(x, y, z) = 2P
 210  		{
 211  			"d3e5183c393c20e4f464acf144ce9ae8266a82b67f553af33eb37e88e7fd2718",
 212  			"5b8f54deb987ec491fb692d3d48f3eebb9454b034365ad480dda0cf079651190",
 213  			"2",
 214  			"dcc3768780c74a0325e2851edad0dc8a566fa61a9e7fc4a34d13dcb509f99bc7",
 215  			"3503be6fb22abd76cb082f8aed63745b9149dd2b037728d32ebfebac99b51f17",
 216  			"3",
 217  			"9f153b13ee7bd915882859635ea9730bf0dc7611b2c7b0e37ee65073c50fabac",
 218  			"2b53702c466dcf6e984a35671756c506c67c2fcb8adb408c44dd125dc91cb988",
 219  			"6e3d537ae61fb1247eda4b4f523cfbaee5152c0d0d96b520376833c2e5944a11",
 220  		},
 221  	}
 222  
 223  	t.Logf("Running %d tests", len(tests))
 224  	for i, test := range tests {
 225  		// Convert hex to field values.
 226  		x1 := new(fieldVal).SetHex(test.x1)
 227  		y1 := new(fieldVal).SetHex(test.y1)
 228  		z1 := new(fieldVal).SetHex(test.z1)
 229  		x2 := new(fieldVal).SetHex(test.x2)
 230  		y2 := new(fieldVal).SetHex(test.y2)
 231  		z2 := new(fieldVal).SetHex(test.z2)
 232  		x3 := new(fieldVal).SetHex(test.x3)
 233  		y3 := new(fieldVal).SetHex(test.y3)
 234  		z3 := new(fieldVal).SetHex(test.z3)
 235  
 236  		// Ensure the test data is using points that are actually on
 237  		// the curve (or the point at infinity).
 238  		if !z1.IsZero() && !isJacobianOnS256Curve(x1, y1, z1) {
 239  			t.Errorf("#%d first point is not on the curve -- "+
 240  				"invalid test data", i)
 241  			continue
 242  		}
 243  		if !z2.IsZero() && !isJacobianOnS256Curve(x2, y2, z2) {
 244  			t.Errorf("#%d second point is not on the curve -- "+
 245  				"invalid test data", i)
 246  			continue
 247  		}
 248  		if !z3.IsZero() && !isJacobianOnS256Curve(x3, y3, z3) {
 249  			t.Errorf("#%d expected point is not on the curve -- "+
 250  				"invalid test data", i)
 251  			continue
 252  		}
 253  
 254  		// Add the two points.
 255  		rx, ry, rz := new(fieldVal), new(fieldVal), new(fieldVal)
 256  		S256().addJacobian(x1, y1, z1, x2, y2, z2, rx, ry, rz)
 257  
 258  		// Ensure result matches expected.
 259  		if !rx.Equals(x3) || !ry.Equals(y3) || !rz.Equals(z3) {
 260  			t.Errorf("#%d wrong result\ngot: (%v, %v, %v)\n"+
 261  				"want: (%v, %v, %v)", i, rx, ry, rz, x3, y3, z3)
 262  			continue
 263  		}
 264  	}
 265  }
 266  
 267  // TestAddAffine tests addition of points in affine coordinates.
 268  func TestAddAffine(t *testing.T) {
 269  	tests := []struct {
 270  		x1, y1 string // Coordinates (in hex) of first point to add
 271  		x2, y2 string // Coordinates (in hex) of second point to add
 272  		x3, y3 string // Coordinates (in hex) of expected point
 273  	}{
 274  		// Addition with a point at infinity (left hand side).
 275  		// ∞ + P = P
 276  		{
 277  			"0",
 278  			"0",
 279  			"d74bf844b0862475103d96a611cf2d898447e288d34b360bc885cb8ce7c00575",
 280  			"131c670d414c4546b88ac3ff664611b1c38ceb1c21d76369d7a7a0969d61d97d",
 281  			"d74bf844b0862475103d96a611cf2d898447e288d34b360bc885cb8ce7c00575",
 282  			"131c670d414c4546b88ac3ff664611b1c38ceb1c21d76369d7a7a0969d61d97d",
 283  		},
 284  		// Addition with a point at infinity (right hand side).
 285  		// P + ∞ = P
 286  		{
 287  			"d74bf844b0862475103d96a611cf2d898447e288d34b360bc885cb8ce7c00575",
 288  			"131c670d414c4546b88ac3ff664611b1c38ceb1c21d76369d7a7a0969d61d97d",
 289  			"0",
 290  			"0",
 291  			"d74bf844b0862475103d96a611cf2d898447e288d34b360bc885cb8ce7c00575",
 292  			"131c670d414c4546b88ac3ff664611b1c38ceb1c21d76369d7a7a0969d61d97d",
 293  		},
 294  
 295  		// Addition with different x values.
 296  		{
 297  			"34f9460f0e4f08393d192b3c5133a6ba099aa0ad9fd54ebccfacdfa239ff49c6",
 298  			"0b71ea9bd730fd8923f6d25a7a91e7dd7728a960686cb5a901bb419e0f2ca232",
 299  			"d74bf844b0862475103d96a611cf2d898447e288d34b360bc885cb8ce7c00575",
 300  			"131c670d414c4546b88ac3ff664611b1c38ceb1c21d76369d7a7a0969d61d97d",
 301  			"fd5b88c21d3143518d522cd2796f3d726793c88b3e05636bc829448e053fed69",
 302  			"21cf4f6a5be5ff6380234c50424a970b1f7e718f5eb58f68198c108d642a137f",
 303  		},
 304  		// Addition with same x opposite y.
 305  		// P(x, y) + P(x, -y) = infinity
 306  		{
 307  			"34f9460f0e4f08393d192b3c5133a6ba099aa0ad9fd54ebccfacdfa239ff49c6",
 308  			"0b71ea9bd730fd8923f6d25a7a91e7dd7728a960686cb5a901bb419e0f2ca232",
 309  			"34f9460f0e4f08393d192b3c5133a6ba099aa0ad9fd54ebccfacdfa239ff49c6",
 310  			"f48e156428cf0276dc092da5856e182288d7569f97934a56fe44be60f0d359fd",
 311  			"0",
 312  			"0",
 313  		},
 314  		// Addition with same point.
 315  		// P(x, y) + P(x, y) = 2P
 316  		{
 317  			"34f9460f0e4f08393d192b3c5133a6ba099aa0ad9fd54ebccfacdfa239ff49c6",
 318  			"0b71ea9bd730fd8923f6d25a7a91e7dd7728a960686cb5a901bb419e0f2ca232",
 319  			"34f9460f0e4f08393d192b3c5133a6ba099aa0ad9fd54ebccfacdfa239ff49c6",
 320  			"0b71ea9bd730fd8923f6d25a7a91e7dd7728a960686cb5a901bb419e0f2ca232",
 321  			"59477d88ae64a104dbb8d31ec4ce2d91b2fe50fa628fb6a064e22582196b365b",
 322  			"938dc8c0f13d1e75c987cb1a220501bd614b0d3dd9eb5c639847e1240216e3b6",
 323  		},
 324  	}
 325  
 326  	t.Logf("Running %d tests", len(tests))
 327  	for i, test := range tests {
 328  		// Convert hex to field values.
 329  		x1, y1 := fromHex(test.x1), fromHex(test.y1)
 330  		x2, y2 := fromHex(test.x2), fromHex(test.y2)
 331  		x3, y3 := fromHex(test.x3), fromHex(test.y3)
 332  
 333  		// Ensure the test data is using points that are actually on
 334  		// the curve (or the point at infinity).
 335  		if !(x1.Sign() == 0 && y1.Sign() == 0) && !S256().IsOnCurve(x1, y1) {
 336  			t.Errorf("#%d first point is not on the curve -- "+
 337  				"invalid test data", i)
 338  			continue
 339  		}
 340  		if !(x2.Sign() == 0 && y2.Sign() == 0) && !S256().IsOnCurve(x2, y2) {
 341  			t.Errorf("#%d second point is not on the curve -- "+
 342  				"invalid test data", i)
 343  			continue
 344  		}
 345  		if !(x3.Sign() == 0 && y3.Sign() == 0) && !S256().IsOnCurve(x3, y3) {
 346  			t.Errorf("#%d expected point is not on the curve -- "+
 347  				"invalid test data", i)
 348  			continue
 349  		}
 350  
 351  		// Add the two points.
 352  		rx, ry := S256().Add(x1, y1, x2, y2)
 353  
 354  		// Ensure result matches expected.
 355  		if rx.Cmp(x3) != 00 || ry.Cmp(y3) != 0 {
 356  			t.Errorf("#%d wrong result\ngot: (%x, %x)\n"+
 357  				"want: (%x, %x)", i, rx, ry, x3, y3)
 358  			continue
 359  		}
 360  	}
 361  }
 362  
 363  // TestDoubleJacobian tests doubling of points projected in Jacobian
 364  // coordinates.
 365  func TestDoubleJacobian(t *testing.T) {
 366  	tests := []struct {
 367  		x1, y1, z1 string // Coordinates (in hex) of point to double
 368  		x3, y3, z3 string // Coordinates (in hex) of expected point
 369  	}{
 370  		// Doubling a point at infinity is still infinity.
 371  		{
 372  			"0",
 373  			"0",
 374  			"0",
 375  			"0",
 376  			"0",
 377  			"0",
 378  		},
 379  		// Doubling with z1=1.
 380  		{
 381  			"34f9460f0e4f08393d192b3c5133a6ba099aa0ad9fd54ebccfacdfa239ff49c6",
 382  			"0b71ea9bd730fd8923f6d25a7a91e7dd7728a960686cb5a901bb419e0f2ca232",
 383  			"1",
 384  			"ec9f153b13ee7bd915882859635ea9730bf0dc7611b2c7b0e37ee64f87c50c27",
 385  			"b082b53702c466dcf6e984a35671756c506c67c2fcb8adb408c44dd0755c8f2a",
 386  			"16e3d537ae61fb1247eda4b4f523cfbaee5152c0d0d96b520376833c1e594464",
 387  		},
 388  		// Doubling with z1!=1.
 389  		{
 390  			"d3e5183c393c20e4f464acf144ce9ae8266a82b67f553af33eb37e88e7fd2718",
 391  			"5b8f54deb987ec491fb692d3d48f3eebb9454b034365ad480dda0cf079651190",
 392  			"2",
 393  			"9f153b13ee7bd915882859635ea9730bf0dc7611b2c7b0e37ee65073c50fabac",
 394  			"2b53702c466dcf6e984a35671756c506c67c2fcb8adb408c44dd125dc91cb988",
 395  			"6e3d537ae61fb1247eda4b4f523cfbaee5152c0d0d96b520376833c2e5944a11",
 396  		},
 397  		// From btcd issue #709.
 398  		{
 399  			"201e3f75715136d2f93c4f4598f91826f94ca01f4233a5bd35de9708859ca50d",
 400  			"bdf18566445e7562c6ada68aef02d498d7301503de5b18c6aef6e2b1722412e1",
 401  			"0000000000000000000000000000000000000000000000000000000000000001",
 402  			"4a5e0559863ebb4e9ed85f5c4fa76003d05d9a7626616e614a1f738621e3c220",
 403  			"00000000000000000000000000000000000000000000000000000001b1388778",
 404  			"7be30acc88bceac58d5b4d15de05a931ae602a07bcb6318d5dedc563e4482993",
 405  		},
 406  	}
 407  
 408  	t.Logf("Running %d tests", len(tests))
 409  	for i, test := range tests {
 410  		// Convert hex to field values.
 411  		x1 := new(fieldVal).SetHex(test.x1)
 412  		y1 := new(fieldVal).SetHex(test.y1)
 413  		z1 := new(fieldVal).SetHex(test.z1)
 414  		x3 := new(fieldVal).SetHex(test.x3)
 415  		y3 := new(fieldVal).SetHex(test.y3)
 416  		z3 := new(fieldVal).SetHex(test.z3)
 417  
 418  		// Ensure the test data is using points that are actually on
 419  		// the curve (or the point at infinity).
 420  		if !z1.IsZero() && !isJacobianOnS256Curve(x1, y1, z1) {
 421  			t.Errorf("#%d first point is not on the curve -- "+
 422  				"invalid test data", i)
 423  			continue
 424  		}
 425  		if !z3.IsZero() && !isJacobianOnS256Curve(x3, y3, z3) {
 426  			t.Errorf("#%d expected point is not on the curve -- "+
 427  				"invalid test data", i)
 428  			continue
 429  		}
 430  
 431  		// Double the point.
 432  		rx, ry, rz := new(fieldVal), new(fieldVal), new(fieldVal)
 433  		S256().doubleJacobian(x1, y1, z1, rx, ry, rz)
 434  
 435  		// Ensure result matches expected.
 436  		if !rx.Equals(x3) || !ry.Equals(y3) || !rz.Equals(z3) {
 437  			t.Errorf("#%d wrong result\ngot: (%v, %v, %v)\n"+
 438  				"want: (%v, %v, %v)", i, rx, ry, rz, x3, y3, z3)
 439  			continue
 440  		}
 441  	}
 442  }
 443  
 444  // TestDoubleAffine tests doubling of points in affine coordinates.
 445  func TestDoubleAffine(t *testing.T) {
 446  	tests := []struct {
 447  		x1, y1 string // Coordinates (in hex) of point to double
 448  		x3, y3 string // Coordinates (in hex) of expected point
 449  	}{
 450  		// Doubling a point at infinity is still infinity.
 451  		// 2*∞ = ∞ (point at infinity)
 452  
 453  		{
 454  			"0",
 455  			"0",
 456  			"0",
 457  			"0",
 458  		},
 459  
 460  		// Random points.
 461  		{
 462  			"e41387ffd8baaeeb43c2faa44e141b19790e8ac1f7ff43d480dc132230536f86",
 463  			"1b88191d430f559896149c86cbcb703193105e3cf3213c0c3556399836a2b899",
 464  			"88da47a089d333371bd798c548ef7caae76e737c1980b452d367b3cfe3082c19",
 465  			"3b6f659b09a362821dfcfefdbfbc2e59b935ba081b6c249eb147b3c2100b1bc1",
 466  		},
 467  		{
 468  			"b3589b5d984f03ef7c80aeae444f919374799edf18d375cab10489a3009cff0c",
 469  			"c26cf343875b3630e15bccc61202815b5d8f1fd11308934a584a5babe69db36a",
 470  			"e193860172998751e527bb12563855602a227fc1f612523394da53b746bb2fb1",
 471  			"2bfcf13d2f5ab8bb5c611fab5ebbed3dc2f057062b39a335224c22f090c04789",
 472  		},
 473  		{
 474  			"2b31a40fbebe3440d43ac28dba23eee71c62762c3fe3dbd88b4ab82dc6a82340",
 475  			"9ba7deb02f5c010e217607fd49d58db78ec273371ea828b49891ce2fd74959a1",
 476  			"2c8d5ef0d343b1a1a48aa336078eadda8481cb048d9305dc4fdf7ee5f65973a2",
 477  			"bb4914ac729e26d3cd8f8dc8f702f3f4bb7e0e9c5ae43335f6e94c2de6c3dc95",
 478  		},
 479  		{
 480  			"61c64b760b51981fab54716d5078ab7dffc93730b1d1823477e27c51f6904c7a",
 481  			"ef6eb16ea1a36af69d7f66524c75a3a5e84c13be8fbc2e811e0563c5405e49bd",
 482  			"5f0dcdd2595f5ad83318a0f9da481039e36f135005420393e72dfca985b482f4",
 483  			"a01c849b0837065c1cb481b0932c441f49d1cab1b4b9f355c35173d93f110ae0",
 484  		},
 485  	}
 486  
 487  	t.Logf("Running %d tests", len(tests))
 488  	for i, test := range tests {
 489  		// Convert hex to field values.
 490  		x1, y1 := fromHex(test.x1), fromHex(test.y1)
 491  		x3, y3 := fromHex(test.x3), fromHex(test.y3)
 492  
 493  		// Ensure the test data is using points that are actually on
 494  		// the curve (or the point at infinity).
 495  		if !(x1.Sign() == 0 && y1.Sign() == 0) && !S256().IsOnCurve(x1, y1) {
 496  			t.Errorf("#%d first point is not on the curve -- "+
 497  				"invalid test data", i)
 498  			continue
 499  		}
 500  		if !(x3.Sign() == 0 && y3.Sign() == 0) && !S256().IsOnCurve(x3, y3) {
 501  			t.Errorf("#%d expected point is not on the curve -- "+
 502  				"invalid test data", i)
 503  			continue
 504  		}
 505  
 506  		// Double the point.
 507  		rx, ry := S256().Double(x1, y1)
 508  
 509  		// Ensure result matches expected.
 510  		if rx.Cmp(x3) != 00 || ry.Cmp(y3) != 0 {
 511  			t.Errorf("#%d wrong result\ngot: (%x, %x)\n"+
 512  				"want: (%x, %x)", i, rx, ry, x3, y3)
 513  			continue
 514  		}
 515  	}
 516  }
 517  
 518  func TestOnCurve(t *testing.T) {
 519  	s256 := S256()
 520  	if !s256.IsOnCurve(s256.Params().Gx, s256.Params().Gy) {
 521  		t.Errorf("FAIL S256")
 522  	}
 523  }
 524  
 525  type baseMultTest struct {
 526  	k    string
 527  	x, y string
 528  }
 529  
 530  //TODO: add more test vectors
 531  var s256BaseMultTests = []baseMultTest{
 532  	{
 533  		"AA5E28D6A97A2479A65527F7290311A3624D4CC0FA1578598EE3C2613BF99522",
 534  		"34F9460F0E4F08393D192B3C5133A6BA099AA0AD9FD54EBCCFACDFA239FF49C6",
 535  		"B71EA9BD730FD8923F6D25A7A91E7DD7728A960686CB5A901BB419E0F2CA232",
 536  	},
 537  	{
 538  		"7E2B897B8CEBC6361663AD410835639826D590F393D90A9538881735256DFAE3",
 539  		"D74BF844B0862475103D96A611CF2D898447E288D34B360BC885CB8CE7C00575",
 540  		"131C670D414C4546B88AC3FF664611B1C38CEB1C21D76369D7A7A0969D61D97D",
 541  	},
 542  	{
 543  		"6461E6DF0FE7DFD05329F41BF771B86578143D4DD1F7866FB4CA7E97C5FA945D",
 544  		"E8AECC370AEDD953483719A116711963CE201AC3EB21D3F3257BB48668C6A72F",
 545  		"C25CAF2F0EBA1DDB2F0F3F47866299EF907867B7D27E95B3873BF98397B24EE1",
 546  	},
 547  	{
 548  		"376A3A2CDCD12581EFFF13EE4AD44C4044B8A0524C42422A7E1E181E4DEECCEC",
 549  		"14890E61FCD4B0BD92E5B36C81372CA6FED471EF3AA60A3E415EE4FE987DABA1",
 550  		"297B858D9F752AB42D3BCA67EE0EB6DCD1C2B7B0DBE23397E66ADC272263F982",
 551  	},
 552  	{
 553  		"1B22644A7BE026548810C378D0B2994EEFA6D2B9881803CB02CEFF865287D1B9",
 554  		"F73C65EAD01C5126F28F442D087689BFA08E12763E0CEC1D35B01751FD735ED3",
 555  		"F449A8376906482A84ED01479BD18882B919C140D638307F0C0934BA12590BDE",
 556  	},
 557  }
 558  
 559  //TODO: test different curves as well?
 560  func TestBaseMult(t *testing.T) {
 561  	s256 := S256()
 562  	for i, e := range s256BaseMultTests {
 563  		k, ok := new(big.Int).SetString(e.k, 16)
 564  		if !ok {
 565  			t.Errorf("%d: bad value for k: %s", i, e.k)
 566  		}
 567  		x, y := s256.ScalarBaseMult(k.Bytes())
 568  		if fmt.Sprintf("%X", x) != e.x || fmt.Sprintf("%X", y) != e.y {
 569  			t.Errorf("%d: bad output for k=%s: got (%X, %X), want (%s, %s)", i, e.k, x, y, e.x, e.y)
 570  		}
 571  		if testing.Short() && i > 5 {
 572  			break
 573  		}
 574  	}
 575  }
 576  
 577  func TestBaseMultVerify(t *testing.T) {
 578  	s256 := S256()
 579  	for bytes := 1; bytes < 40; bytes++ {
 580  		for i := 0; i < 30; i++ {
 581  			data := make([]byte, bytes)
 582  			_, err := rand.Read(data)
 583  			if err != nil {
 584  				t.Errorf("failed to read random data for %d", i)
 585  				continue
 586  			}
 587  			x, y := s256.ScalarBaseMult(data)
 588  			xWant, yWant := s256.ScalarMult(s256.Gx, s256.Gy, data)
 589  			if x.Cmp(xWant) != 0 || y.Cmp(yWant) != 0 {
 590  				t.Errorf("%d: bad output for %X: got (%X, %X), want (%X, %X)", i, data, x, y, xWant, yWant)
 591  			}
 592  			if testing.Short() && i > 2 {
 593  				break
 594  			}
 595  		}
 596  	}
 597  }
 598  
 599  func TestScalarMult(t *testing.T) {
 600  	tests := []struct {
 601  		x  string
 602  		y  string
 603  		k  string
 604  		rx string
 605  		ry string
 606  	}{
 607  		// base mult, essentially.
 608  		{
 609  			"79be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798",
 610  			"483ada7726a3c4655da4fbfc0e1108a8fd17b448a68554199c47d08ffb10d4b8",
 611  			"18e14a7b6a307f426a94f8114701e7c8e774e7f9a47e2c2035db29a206321725",
 612  			"50863ad64a87ae8a2fe83c1af1a8403cb53f53e486d8511dad8a04887e5b2352",
 613  			"2cd470243453a299fa9e77237716103abc11a1df38855ed6f2ee187e9c582ba6",
 614  		},
 615  		// From btcd issue #709.
 616  		{
 617  			"000000000000000000000000000000000000000000000000000000000000002c",
 618  			"420e7a99bba18a9d3952597510fd2b6728cfeafc21a4e73951091d4d8ddbe94e",
 619  			"a2e8ba2e8ba2e8ba2e8ba2e8ba2e8ba219b51835b55cc30ebfe2f6599bc56f58",
 620  			"a2112dcdfbcd10ae1133a358de7b82db68e0a3eb4b492cc8268d1e7118c98788",
 621  			"27fc7463b7bb3c5f98ecf2c84a6272bb1681ed553d92c69f2dfe25a9f9fd3836",
 622  		},
 623  	}
 624  
 625  	s256 := S256()
 626  	for i, test := range tests {
 627  		x, _ := new(big.Int).SetString(test.x, 16)
 628  		y, _ := new(big.Int).SetString(test.y, 16)
 629  		k, _ := new(big.Int).SetString(test.k, 16)
 630  		xWant, _ := new(big.Int).SetString(test.rx, 16)
 631  		yWant, _ := new(big.Int).SetString(test.ry, 16)
 632  		xGot, yGot := s256.ScalarMult(x, y, k.Bytes())
 633  		if xGot.Cmp(xWant) != 0 || yGot.Cmp(yWant) != 0 {
 634  			t.Fatalf("%d: bad output: got (%X, %X), want (%X, %X)", i, xGot, yGot, xWant, yWant)
 635  		}
 636  	}
 637  }
 638  
 639  func TestScalarMultRand(t *testing.T) {
 640  	// Strategy for this test:
 641  	// Get a random exponent from the generator point at first
 642  	// This creates a new point which is used in the next iteration
 643  	// Use another random exponent on the new point.
 644  	// We use BaseMult to verify by multiplying the previous exponent
 645  	// and the new random exponent together (mod N)
 646  	s256 := S256()
 647  	x, y := s256.Gx, s256.Gy
 648  	exponent := big.NewInt(1)
 649  	for i := 0; i < 1024; i++ {
 650  		data := make([]byte, 32)
 651  		_, err := rand.Read(data)
 652  		if err != nil {
 653  			t.Fatalf("failed to read random data at %d", i)
 654  			break
 655  		}
 656  		x, y = s256.ScalarMult(x, y, data)
 657  		exponent.Mul(exponent, new(big.Int).SetBytes(data))
 658  		xWant, yWant := s256.ScalarBaseMult(exponent.Bytes())
 659  		if x.Cmp(xWant) != 0 || y.Cmp(yWant) != 0 {
 660  			t.Fatalf("%d: bad output for %X: got (%X, %X), want (%X, %X)", i, data, x, y, xWant, yWant)
 661  			break
 662  		}
 663  	}
 664  }
 665  
 666  func TestSplitK(t *testing.T) {
 667  	tests := []struct {
 668  		k      string
 669  		k1, k2 string
 670  		s1, s2 int
 671  	}{
 672  		{
 673  			"6df2b5d30854069ccdec40ae022f5c948936324a4e9ebed8eb82cfd5a6b6d766",
 674  			"00000000000000000000000000000000b776e53fb55f6b006a270d42d64ec2b1",
 675  			"00000000000000000000000000000000d6cc32c857f1174b604eefc544f0c7f7",
 676  			-1, -1,
 677  		},
 678  		{
 679  			"6ca00a8f10632170accc1b3baf2a118fa5725f41473f8959f34b8f860c47d88d",
 680  			"0000000000000000000000000000000007b21976c1795723c1bfbfa511e95b84",
 681  			"00000000000000000000000000000000d8d2d5f9d20fc64fd2cf9bda09a5bf90",
 682  			1, -1,
 683  		},
 684  		{
 685  			"b2eda8ab31b259032d39cbc2a234af17fcee89c863a8917b2740b67568166289",
 686  			"00000000000000000000000000000000507d930fecda7414fc4a523b95ef3c8c",
 687  			"00000000000000000000000000000000f65ffb179df189675338c6185cb839be",
 688  			-1, -1,
 689  		},
 690  		{
 691  			"f6f00e44f179936f2befc7442721b0633f6bafdf7161c167ffc6f7751980e3a0",
 692  			"0000000000000000000000000000000008d0264f10bcdcd97da3faa38f85308d",
 693  			"0000000000000000000000000000000065fed1506eb6605a899a54e155665f79",
 694  			-1, -1,
 695  		},
 696  		{
 697  			"8679085ab081dc92cdd23091ce3ee998f6b320e419c3475fae6b5b7d3081996e",
 698  			"0000000000000000000000000000000089fbf24fbaa5c3c137b4f1cedc51d975",
 699  			"00000000000000000000000000000000d38aa615bd6754d6f4d51ccdaf529fea",
 700  			-1, -1,
 701  		},
 702  		{
 703  			"6b1247bb7931dfcae5b5603c8b5ae22ce94d670138c51872225beae6bba8cdb3",
 704  			"000000000000000000000000000000008acc2a521b21b17cfb002c83be62f55d",
 705  			"0000000000000000000000000000000035f0eff4d7430950ecb2d94193dedc79",
 706  			-1, -1,
 707  		},
 708  		{
 709  			"a2e8ba2e8ba2e8ba2e8ba2e8ba2e8ba219b51835b55cc30ebfe2f6599bc56f58",
 710  			"0000000000000000000000000000000045c53aa1bb56fcd68c011e2dad6758e4",
 711  			"00000000000000000000000000000000a2e79d200f27f2360fba57619936159b",
 712  			-1, -1,
 713  		},
 714  	}
 715  
 716  	s256 := S256()
 717  	for i, test := range tests {
 718  		k, ok := new(big.Int).SetString(test.k, 16)
 719  		if !ok {
 720  			t.Errorf("%d: bad value for k: %s", i, test.k)
 721  		}
 722  		k1, k2, k1Sign, k2Sign := s256.splitK(k.Bytes())
 723  		k1str := fmt.Sprintf("%064x", k1)
 724  		if test.k1 != k1str {
 725  			t.Errorf("%d: bad k1: got %v, want %v", i, k1str, test.k1)
 726  		}
 727  		k2str := fmt.Sprintf("%064x", k2)
 728  		if test.k2 != k2str {
 729  			t.Errorf("%d: bad k2: got %v, want %v", i, k2str, test.k2)
 730  		}
 731  		if test.s1 != k1Sign {
 732  			t.Errorf("%d: bad k1 sign: got %d, want %d", i, k1Sign, test.s1)
 733  		}
 734  		if test.s2 != k2Sign {
 735  			t.Errorf("%d: bad k2 sign: got %d, want %d", i, k2Sign, test.s2)
 736  		}
 737  		k1Int := new(big.Int).SetBytes(k1)
 738  		k1SignInt := new(big.Int).SetInt64(int64(k1Sign))
 739  		k1Int.Mul(k1Int, k1SignInt)
 740  		k2Int := new(big.Int).SetBytes(k2)
 741  		k2SignInt := new(big.Int).SetInt64(int64(k2Sign))
 742  		k2Int.Mul(k2Int, k2SignInt)
 743  		gotK := new(big.Int).Mul(k2Int, s256.lambda)
 744  		gotK.Add(k1Int, gotK)
 745  		gotK.Mod(gotK, s256.N)
 746  		if k.Cmp(gotK) != 0 {
 747  			t.Errorf("%d: bad k: got %X, want %X", i, gotK.Bytes(), k.Bytes())
 748  		}
 749  	}
 750  }
 751  
 752  func TestSplitKRand(t *testing.T) {
 753  	s256 := S256()
 754  	for i := 0; i < 1024; i++ {
 755  		bytesK := make([]byte, 32)
 756  		_, err := rand.Read(bytesK)
 757  		if err != nil {
 758  			t.Fatalf("failed to read random data at %d", i)
 759  			break
 760  		}
 761  		k := new(big.Int).SetBytes(bytesK)
 762  		k1, k2, k1Sign, k2Sign := s256.splitK(bytesK)
 763  		k1Int := new(big.Int).SetBytes(k1)
 764  		k1SignInt := new(big.Int).SetInt64(int64(k1Sign))
 765  		k1Int.Mul(k1Int, k1SignInt)
 766  		k2Int := new(big.Int).SetBytes(k2)
 767  		k2SignInt := new(big.Int).SetInt64(int64(k2Sign))
 768  		k2Int.Mul(k2Int, k2SignInt)
 769  		gotK := new(big.Int).Mul(k2Int, s256.lambda)
 770  		gotK.Add(k1Int, gotK)
 771  		gotK.Mod(gotK, s256.N)
 772  		if k.Cmp(gotK) != 0 {
 773  			t.Errorf("%d: bad k: got %X, want %X", i, gotK.Bytes(), k.Bytes())
 774  		}
 775  	}
 776  }
 777  
 778  // Test this curve's usage with the ecdsa package.
 779  
 780  func testKeyGeneration(t *testing.T, c *KoblitzCurve, tag string) {
 781  	priv, err := NewPrivateKey(c)
 782  	if err != nil {
 783  		t.Errorf("%s: error: %s", tag, err)
 784  		return
 785  	}
 786  	if !c.IsOnCurve(priv.PublicKey.X, priv.PublicKey.Y) {
 787  		t.Errorf("%s: public key invalid: %s", tag, err)
 788  	}
 789  }
 790  
 791  func TestKeyGeneration(t *testing.T) {
 792  	testKeyGeneration(t, S256(), "S256")
 793  }
 794  
 795  func testSignAndVerify(t *testing.T, c *KoblitzCurve, tag string) {
 796  	priv, _ := NewPrivateKey(c)
 797  	pub := priv.PubKey()
 798  
 799  	hashed := []byte("testing")
 800  	sig, err := priv.Sign(hashed)
 801  	if err != nil {
 802  		t.Errorf("%s: error signing: %s", tag, err)
 803  		return
 804  	}
 805  
 806  	if !sig.Verify(hashed, pub) {
 807  		t.Errorf("%s: Verify failed", tag)
 808  	}
 809  
 810  	hashed[0] ^= 0xff
 811  	if sig.Verify(hashed, pub) {
 812  		t.Errorf("%s: Verify always works!", tag)
 813  	}
 814  }
 815  
 816  func TestSignAndVerify(t *testing.T) {
 817  	testSignAndVerify(t, S256(), "S256")
 818  }
 819  
 820  func TestNAF(t *testing.T) {
 821  	tests := []string{
 822  		"6df2b5d30854069ccdec40ae022f5c948936324a4e9ebed8eb82cfd5a6b6d766",
 823  		"b776e53fb55f6b006a270d42d64ec2b1",
 824  		"d6cc32c857f1174b604eefc544f0c7f7",
 825  		"45c53aa1bb56fcd68c011e2dad6758e4",
 826  		"a2e79d200f27f2360fba57619936159b",
 827  	}
 828  	negOne := big.NewInt(-1)
 829  	one := big.NewInt(1)
 830  	two := big.NewInt(2)
 831  	for i, test := range tests {
 832  		want, _ := new(big.Int).SetString(test, 16)
 833  		nafPos, nafNeg := NAF(want.Bytes())
 834  		got := big.NewInt(0)
 835  		// Check that the NAF representation comes up with the right number
 836  		for i := 0; i < len(nafPos); i++ {
 837  			bytePos := nafPos[i]
 838  			byteNeg := nafNeg[i]
 839  			for j := 7; j >= 0; j-- {
 840  				got.Mul(got, two)
 841  				if bytePos&0x80 == 0x80 {
 842  					got.Add(got, one)
 843  				} else if byteNeg&0x80 == 0x80 {
 844  					got.Add(got, negOne)
 845  				}
 846  				bytePos <<= 1
 847  				byteNeg <<= 1
 848  			}
 849  		}
 850  		if got.Cmp(want) != 0 {
 851  			t.Errorf("%d: Failed NAF got %X want %X", i, got, want)
 852  		}
 853  	}
 854  }
 855  
 856  func TestNAFRand(t *testing.T) {
 857  	negOne := big.NewInt(-1)
 858  	one := big.NewInt(1)
 859  	two := big.NewInt(2)
 860  	for i := 0; i < 1024; i++ {
 861  		data := make([]byte, 32)
 862  		_, err := rand.Read(data)
 863  		if err != nil {
 864  			t.Fatalf("failed to read random data at %d", i)
 865  			break
 866  		}
 867  		nafPos, nafNeg := NAF(data)
 868  		want := new(big.Int).SetBytes(data)
 869  		got := big.NewInt(0)
 870  		// Check that the NAF representation comes up with the right number
 871  		for i := 0; i < len(nafPos); i++ {
 872  			bytePos := nafPos[i]
 873  			byteNeg := nafNeg[i]
 874  			for j := 7; j >= 0; j-- {
 875  				got.Mul(got, two)
 876  				if bytePos&0x80 == 0x80 {
 877  					got.Add(got, one)
 878  				} else if byteNeg&0x80 == 0x80 {
 879  					got.Add(got, negOne)
 880  				}
 881  				bytePos <<= 1
 882  				byteNeg <<= 1
 883  			}
 884  		}
 885  		if got.Cmp(want) != 0 {
 886  			t.Errorf("%d: Failed NAF got %X want %X", i, got, want)
 887  		}
 888  	}
 889  }
 890