Revert changes done to crypto to make it less random (#154)

* Revert "Issue 70 (#153)"

This reverts commit a20ac58.

* Deprecate Bech32AddressWithLength, Bech32Address, P2SHAddress, P2PKHAddressWithLength, P2PKHAddress

---------

Co-authored-by: Jonathan Schweder <jonathanschweder@amazon.com>

crypto.go

@@ -1,80 +1,121 @@
 package faker
 
+import (
+	"strings"
+)
+
 // Crypto is a faker struct for generating bitcoin data
 type Crypto struct {
 	Faker *Faker
 }
 
 var (
-	bitcoinAddresses = []string{
-		"1JyxpLZzvYP2TyXaQV3J3vwajJz4hbxtRC",
-		"1JyVFJVUNx8RQrjyNCGDe7BQ62wPyxU8bC",
-		"1JVcPDeBfGP5PmNZwnJSfms7hKLncMSenV",
-		"1FwiYqdgLH6w5XdB9QXgZGi7ZHGiyUYucT",
-		"1H3nknk2Pdav9LjXyfLd8umqPC57ZQbN4",
-		"1DMwH1FMx2yJ67az7ZTJqViBD6iz3vQkUK",
-		"1JzvBX9Q86LbEcBxT58npYXS31QexVVMGG",
-		"1HBTfs2QLK459tQrdpeQs4stR25GWwJTui",
-		"1NZMxDpqB1ehEdvGJeAs9Gdmh3dXfUfAZB",
-		"19ePAsmdkM4u9e3euzfnQa1AXEoD2UgmEj",
-	}
+	bitcoinMin = 26
+	bitcoinMax = 35
+	ethLen     = 42
+	ethPrefix  = "0x"
+)
 
-	etheriumAddresses = []string{
-		"0x83e1e8f10092d42db425D81c2e99f312a7E011aA",
-		"0xd3E823D4C999e4ef9c92835eEF6906E519C13251",
-		"0x4e3adfcdD456DDe868B1225aA0ed103Dd188B5F6",
-		"0xbC39DCa632f8f7f2A94B095d48bcEE779d961728",
-		"0xE0A6c75e545947E7Bb4dde2D8182762a4C698E5c",
-		"0x45C20Fd8F6B07359750f92B79f1C41754Bd09Ac3",
-		"0xA882bE0b4C10E91c3565EE01878A48F9B940f2c5",
-		"0x8c2B7B23f01fcAD2946A3C214c4D96338A5eFD6D",
-		"0x271253c6B815a07506719116262c1673692eD76E",
-		"0x1e887dC08ba56e369E68987F9D82b44065677c87",
+// Checks whether the ascii value provided is in the exclusion for bitcoin.
+func (Crypto) isInExclusionZone(ascii int) bool {
+	switch ascii {
+	// Ascii for uppercase letter "O", uppercase letter "I", lowercase letter "l", and the number "0"
+	case 48, 73, 79, 108:
+		return true
 	}
-)
+	return false
+}
 
-// BitcoinAddress returns a valid address of either Bech32, P2PKH, or P2SH type.
-func (c Crypto) BitcoinAddress() string {
-	return c.Faker.RandomStringElement(bitcoinAddresses)
+// algorithmRange decides whether to get digit, uppercase, or lowercase. returns the ascii range to do IntBetween on
+func (c Crypto) algorithmRange() (int, int) {
+	dec := c.Faker.IntBetween(0, 2)
+	if dec == 0 {
+		// digit
+		return 48, 57
+	} else if dec == 1 {
+		// upper
+		return 65, 90
+	}
+	// lower
+	return 97, 122
 }
 
-// EtheriumAddress returns a valid hexadecimal ethereum address of 42 characters.
-func (c Crypto) EtheriumAddress() string {
-	return c.Faker.RandomStringElement(etheriumAddresses)
+// generateBicoinAddress returns a bitcoin address with a given prefix and length
+func (c Crypto) generateBicoinAddress(length int, prefix string, f *Faker) string {
+	address := []string{prefix}
+
+	for i := 0; i < length; i++ {
+		asciiStart, asciiEnd := c.algorithmRange()
+		val := f.IntBetween(asciiStart, asciiEnd)
+		if c.isInExclusionZone(val) {
+			val++
+		}
+		address = append(address, string(rune(val)))
+	}
+	return strings.Join(address, "")
 }
 
 // P2PKHAddress generates a P2PKH bitcoin address.
-// Deprecated: Use BitcoinAddress instead.
+// Deprecated: Please use BitcoinAddress instead.
 func (c Crypto) P2PKHAddress() string {
-	return "1" + c.BitcoinAddress()[1:]
+	length := c.Faker.IntBetween(bitcoinMin, bitcoinMax)
+	// subtract 1 for prefix
+	return c.generateBicoinAddress(length-1, "1", c.Faker)
 }
 
 // P2PKHAddressWithLength generates a P2PKH bitcoin address with specified length.
-// Deprecated: Use BitcoinAddress instead.
+// Deprecated: Please use BitcoinAddress instead.
 func (c Crypto) P2PKHAddressWithLength(length int) string {
-	return "1" + c.P2PKHAddress()[1:length-1]
+	return c.generateBicoinAddress(length-1, "1", c.Faker)
 }
 
 // P2SHAddress generates a P2SH bitcoin address.
-// Deprecated: Use BitcoinAddress instead.
+// Deprecated: Please use BitcoinAddress instead.
 func (c Crypto) P2SHAddress() string {
-	return "3" + c.BitcoinAddress()[1:]
+	length := c.Faker.IntBetween(bitcoinMin, bitcoinMax)
+	// subtract 1 for prefix
+	return c.generateBicoinAddress(length-1, "3", c.Faker)
 }
 
 // P2SHAddressWithLength generates a P2PKH bitcoin address with specified length.
-// Deprecated: Use BitcoinAddress instead.
+// Deprecated: Please use BitcoinAddress instead.
 func (c Crypto) P2SHAddressWithLength(length int) string {
-	return "3" + c.P2SHAddress()[1:length-1]
+	return c.generateBicoinAddress(length-1, "3", c.Faker)
 }
 
 // Bech32Address generates a Bech32 bitcoin address
-// Deprecated: Use BitcoinAddress instead.
+// Deprecated: Please use BitcoinAddress instead.
 func (c Crypto) Bech32Address() string {
-	return "bc1" + c.BitcoinAddress()[3:]
+	length := c.Faker.IntBetween(bitcoinMin, bitcoinMax)
+	// subtract 1 for prefix
+	return c.generateBicoinAddress(length-3, "bc1", c.Faker)
 }
 
 // Bech32AddressWithLength generates a Bech32 bitcoin address with specified length.
-// Deprecated: Use BitcoinAddress instead.
+// Deprecated: Please use BitcoinAddress instead.
 func (c Crypto) Bech32AddressWithLength(length int) string {
-	return "bc1" + c.Bech32Address()[3:length-3]
+	return c.generateBicoinAddress(length-3, "bc1", c.Faker)
+}
+
+// BitcoinAddress returns an address of either Bech32, P2PKH, or P2SH type.
+func (c Crypto) BitcoinAddress() string {
+	dec := c.Faker.IntBetween(0, 2)
+	if dec == 0 {
+		return c.Bech32Address()
+	} else if dec == 1 {
+		return c.P2SHAddress()
+	}
+	return c.P2PKHAddress()
+}
+
+// EtheriumAddress returns a hexadecimal ethereum address of 42 characters.
+func (c Crypto) EtheriumAddress() string {
+	address := []string{ethPrefix}
+
+	for i := 0; i < ethLen-2; i++ {
+		asciiStart, asciiEnd := c.algorithmRange()
+		val := c.Faker.IntBetween(asciiStart, asciiEnd)
+		address = append(address, string(rune(val)))
+	}
+	return strings.Join(address, "")
 }

crypto_test.go

@@ -1,61 +1,199 @@
 package faker
 
 import (
+	"fmt"
 	"strings"
 	"testing"
 )
 
-func TestBitcoinAddress(t *testing.T) {
+var (
+	bannedBitcoin      = []string{"O", "I", "l", "0"}
+	validBitcoinPrefix = map[string]string{
+		"p2pkh":  "1",
+		"p2sh":   "3",
+		"bech32": "bc1",
+	}
+	validEthPrefix = "0x"
+)
+
+type GeneratorMock struct {
+	local int
+}
+
+func (g GeneratorMock) Intn(_ int) int {
+	return g.local
+}
+
+func (g GeneratorMock) Int() int {
+	return g.local
+}
+
+type TestCaseAlnum struct {
+	desc     string
+	localInt int
+	assert   func(t *testing.T, a int, b int)
+}
+
+type TestCaseRandomBitcoin struct {
+	desc              string
+	localInt          int
+	expectedSubstring string
+}
+
+func TestIsInExclusionZone(t *testing.T) {
 	c := New().Crypto()
-	addr := c.BitcoinAddress()
-	Expect(t, false, addr == "")
+	for _, address := range bannedBitcoin {
+		Expect(t, true, c.isInExclusionZone(int(rune(address[0]))))
+	}
+	// take any banned rune and + 1 it to get a valid character
+	Expect(t, false, c.isInExclusionZone(int(rune(bannedBitcoin[0][0]))+1))
 }
 
-func TestEtheriumAddress(t *testing.T) {
+func TestGenerateBicoinAddress(t *testing.T) {
 	c := New().Crypto()
-	addr := c.EtheriumAddress()
-	Expect(t, false, addr == "")
-	Expect(t, true, strings.HasPrefix(addr, "0x"))
+	length := c.Faker.IntBetween(5, 10)
+	Expect(t, length+1, len(c.generateBicoinAddress(length, "a", c.Faker)))
 }
 
 func TestP2PKHAddress(t *testing.T) {
 	c := New().Crypto()
 	addr := c.P2PKHAddress()
-	Expect(t, false, addr == "")
-	Expect(t, true, strings.HasPrefix(addr, "1"))
+	Expect(t, true, len(addr) >= bitcoinMin)
+	Expect(t, true, len(addr) <= bitcoinMax)
+	Expect(t, true, strings.HasPrefix(addr, validBitcoinPrefix["p2pkh"]))
+	for i := 0; i < len(bannedBitcoin); i++ {
+		Expect(t, true, !strings.Contains(addr, bannedBitcoin[i]))
+	}
 }
 
 func TestP2PKHAddressWithLength(t *testing.T) {
 	c := New().Crypto()
-	addr := c.P2PKHAddressWithLength(10)
-	Expect(t, false, addr == "")
-	Expect(t, true, strings.HasPrefix(addr, "1"))
+	length := c.Faker.IntBetween(26, 62)
+	addr := c.P2PKHAddressWithLength(length)
+	Expect(t, true, len(addr) == length)
+	Expect(t, true, strings.HasPrefix(addr, validBitcoinPrefix["p2pkh"]))
 }
 
 func TestP2SHAddress(t *testing.T) {
 	c := New().Crypto()
 	addr := c.P2SHAddress()
-	Expect(t, false, addr == "")
-	Expect(t, true, strings.HasPrefix(addr, "3"))
+	Expect(t, true, len(addr) >= bitcoinMin)
+	Expect(t, true, len(addr) <= bitcoinMax)
+	Expect(t, true, strings.HasPrefix(addr, validBitcoinPrefix["p2sh"]))
+	for i := 0; i < len(bannedBitcoin); i++ {
+		Expect(t, true, !strings.Contains(addr, bannedBitcoin[i]))
+	}
 }
 
 func TestP2SHAddressWithLength(t *testing.T) {
 	c := New().Crypto()
-	addr := c.P2SHAddressWithLength(10)
-	Expect(t, false, addr == "")
-	Expect(t, true, strings.HasPrefix(addr, "3"))
+	length := c.Faker.IntBetween(26, 62)
+	addr := c.P2SHAddressWithLength(length)
+	Expect(t, true, len(addr) == length)
+	Expect(t, true, strings.HasPrefix(addr, validBitcoinPrefix["p2sh"]))
 }
 
 func TestBech32Address(t *testing.T) {
 	c := New().Crypto()
 	addr := c.Bech32Address()
-	Expect(t, false, addr == "")
-	Expect(t, true, strings.HasPrefix(addr, "bc1"))
+	Expect(t, true, len(addr) >= bitcoinMin)
+	Expect(t, true, len(addr) <= bitcoinMax)
+	Expect(t, true, strings.HasPrefix(addr, validBitcoinPrefix["bech32"]))
+	for i := 0; i < len(bannedBitcoin); i++ {
+		Expect(t, true, !strings.Contains(addr, bannedBitcoin[i]))
+	}
 }
 
 func TestBech32AddressWithLength(t *testing.T) {
 	c := New().Crypto()
-	addr := c.Bech32AddressWithLength(10)
-	Expect(t, false, addr == "")
-	Expect(t, true, strings.HasPrefix(addr, "bc1"))
+	length := c.Faker.IntBetween(26, 62)
+	addr := c.Bech32AddressWithLength(length)
+	Expect(t, true, len(addr) == length)
+	Expect(t, true, strings.HasPrefix(addr, validBitcoinPrefix["bech32"]))
+}
+
+func TestEtheriumAddress(t *testing.T) {
+	c := New().Crypto()
+	addr := c.EtheriumAddress()
+	Expect(t, true, len(addr) == ethLen)
+	Expect(t, true, strings.HasPrefix(addr, ethPrefix))
+}
+
+func TestAlgorithmRange(t *testing.T) {
+	for k, tc := range []TestCaseAlnum{
+		{
+			// The Description of the test case
+			desc:     "Test Get Digit 0-9",
+			localInt: 0,
+			// Our anticipated result
+			assert: func(t *testing.T, a int, b int) {
+				Expect(t, true, a == int('0'))
+				Expect(t, true, b == int('9'))
+			},
+		},
+		{
+			desc:     "Test Get Uppercase A-Z",
+			localInt: 1,
+			assert: func(t *testing.T, a int, b int) {
+				Expect(t, true, a == int('A'))
+				Expect(t, true, b == int('Z'))
+			},
+		},
+		{
+			desc:     "Test Get Lowercase a-z",
+			localInt: 2,
+			assert: func(t *testing.T, a int, b int) {
+				Expect(t, true, a == int('a'))
+				Expect(t, true, b == int('z'))
+			},
+		},
+	} {
+		t.Run(fmt.Sprintf("case=%d/description=%s", k, tc.desc), func(t *testing.T) {
+			// Use our mock here instead of using a seed.
+			gen := GeneratorMock{}
+			gen.local = tc.localInt
+			// populate the generator with our mock as it is an interface.
+			c := Faker{Generator: gen}
+			a, b := c.Crypto().algorithmRange()
+			tc.assert(t, a, b)
+		})
+	}
+}
+
+func TestRandomBitcoin(t *testing.T) {
+	for k, tc := range []TestCaseRandomBitcoin{
+		{
+			// The Description of the test case
+			desc:     "Test Get Bech32",
+			localInt: 0,
+			// Our anticipated result
+			expectedSubstring: "bc1",
+		},
+		{
+			// The Description of the test case
+			desc:     "Test Get P2SH",
+			localInt: 1,
+			// Our anticipated result
+			expectedSubstring: "3",
+		},
+		{
+			// The Description of the test case
+			desc:     "Test Get P2PKH",
+			localInt: 2,
+			// Our anticipated result
+			expectedSubstring: "1",
+		},
+	} {
+		t.Run(fmt.Sprintf("case=%d/description=%s", k, tc.desc), func(t *testing.T) {
+			// Use our mock here instead of using a seed.
+			gen := GeneratorMock{}
+			gen.local = tc.localInt
+			// populate the generator with our mock as it is an interface.
+			c := Faker{Generator: gen}
+			rs := c.Crypto().BitcoinAddress()
+			Expect(t, true, strings.HasPrefix(rs, tc.expectedSubstring))
+			Expect(t, true, len(rs) >= bitcoinMin)
+			Expect(t, true, len(rs) <= bitcoinMax)
+		})
+	}
 }