Set 1, Challenge 2

set1/challenge_2.go

@@ -0,0 +1,38 @@
+package set1
+
+func XORHexString(content, password string) string {
+	var hexValues = map[byte]byte{
+		'0': 0,
+		'1': 1,
+		'2': 2,
+		'3': 3,
+		'4': 4,
+		'5': 5,
+		'6': 6,
+		'7': 7,
+		'8': 8,
+		'9': 9,
+		'a': 10,
+		'b': 11,
+		'c': 12,
+		'd': 13,
+		'e': 14,
+		'f': 15,
+	}
+
+	var hexRepresentations = []byte{'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'}
+
+	contentBytes := []byte(content)
+	passwordBytes := []byte(password)
+
+	buffer := make([]byte, len(contentBytes), len(contentBytes))
+
+	for i := 0; i < len(contentBytes); i++ {
+		contentByte := hexValues[contentBytes[i]]
+		passwordByte := hexValues[passwordBytes[i]]
+
+		buffer[i] = hexRepresentations[contentByte^passwordByte]
+	}
+
+	return string(buffer)
+}

test/set_1_test.go

@@ -17,3 +17,16 @@ func Test_Challenge1(t *testing.T) {
 		t.Fatal("Set 1, Challenge 1 has failed")
 	}
 }
+
+func Test_Challenge2(t *testing.T) {
+	const expected = "746865206b696420646f6e277420706c6179"
+
+	const content = "1c0111001f010100061a024b53535009181c"
+	const password = "686974207468652062756c6c277320657965"
+
+	value := set1.XORHexString(content, password)
+
+	if value != expected {
+		t.Fatal(("Set 1, Challenge 2 has failed"))
+	}
+}