老笔记整理六：MD5的小作死
MD5算法具有以下特点：
1、压缩性：任意长度的数据，算出的MD5值长度都是固定的。
2、容易计算：从原数据计算出MD5值很容易。
3、抗修改性：对原数据进行任何改动，哪怕只修改1个字节，所得到的MD5值都有很大区别。
4、弱抗碰撞：已知原数据和其MD5值，想找到一个具有相同MD5值的数据（即伪造数据）是非常困难的。
5、强抗碰撞：想找到两个不同的数据，使它们具有相同的MD5值，是非常困难的。
然后我就在想，如果把一个字符串用MD5加密过以后再不停的进行MD5加密，会得到什么样的结果呢？遂有了以下代码：
using System;
using System.IO;
using System.Text;
using System.Security.Cryptography;
namespace MD5puzzle
{
class Program
{
static void Main(string[] args)
{
Int64 i = 0, j = 0;
Int64 max = 10000000;
string niconiconi = "niconiconi";
string niconi, nico=niconiconi;
StreamWriter swOut = new StreamWriter(@"E:\md5.txt", false, Encoding.Default);
for (i = 0; (i < max) && (j == 0); i++)
{
niconi = does.MD5(nico);
if (niconi == niconiconi)
{
j = 1;
}
swOut.WriteLine(niconi + " " + i);
nico = niconi;
}
System.Console.WriteLine("Finish");
System.Console.Read();
}
public void domd5p()
{
Int64 i = 0, j = 0;
Int64 max = 100000000;
string nico = does.MD5("niconiconi");
string niconi;
for (i = 0; (i < max) && (j == 0); i++)
{
niconi = does.MD5(nico);
if (niconi == nico)
{
j = 1;
}
System.Console.WriteLine("NO." + i + "_" + niconi);
nico = niconi;
}
System.Console.Read();
}
}
class does
{
public static string MD5(string Sourcein)
{
MD5CryptoServiceProvider MD5CSP = new MD5CryptoServiceProvider();
byte[] MD5Source = System.Text.Encoding.UTF8.GetBytes(Sourcein);
byte[] MD5Out = MD5CSP.ComputeHash(MD5Source);
return Convert.ToBase64String(MD5Out);
}
}
}
这里我把数据写到了md5.txt里。
当中改动过上限。括号里面的是上限，大家可以感受一下
没错，那个只有5百万次的已经有160MB了。我家的电脑实在比较无能。我玩到5百万就玩不下去了，有兴趣的同学可以下下来去试试。下面贴出前100个md5码
rRIpUGNjjelWrYVo1BInLA== 0
UrjRsTpLZN0WL72SDuid4w== 1
6MICH12/VVlQPlcqAyy3Aw== 2
3dOqdPJsUmBXwLAQaDGGHQ== 3
T+DsqpgWx5k/uZMtY5V1ig== 4
nMD0ewc/sG4F48SFyapgyA== 5
yYQi6mMUkxq8Hrf096EkKw== 6
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h/9vU01bY5OQvCzgFiPzKA== 8
iUg4RSM4dc+C42bA7tddVQ== 9
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5Dpk6YBnDklIi/hpodU2sQ== 12
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aRX22z67lAsOqtTH+Tw8cQ== 14
lDklDi/l3/evDZxpPMgueQ== 15
FwaH5M0IfUFI8JxSGhhXhw== 16
Fl/Nn0ndML7kAzVy7eBz2Q== 17
721lIGZeXmLWUJFLoVKnzw== 18
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Ka8JEiL243jL3Af6sEPFvg== 20
A/IjZkj0a9HuHeTbOOiVsw== 21
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IqrobIoalFbAF1Ien1/zAg== 32
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e5qvFWng2siIbBiqCtWzxw== 43
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BJxt/vpHsDVfizCvl5uRBg== 60
P/9excuqnyAxugIY4SLGgA== 61
O2qqoVKGa2RcW9b516d6Ww== 62
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hgWxbnIiZwXIYQ4FBSXTGg== 64
O7cxBcVgMD3ayM1H83cOhA== 65
x2xN7L/jccWH32bzzhk9ag== 66
setWXmUwVLncbIVZbnrVrg== 67
PgKpptzklLuLySSwU+zrJg== 68
fcHiicljN4dxG14Mer3ZAQ== 69
XG/9yosdOJ5NeeyP6JSG9A== 70
ETG8Fold3DHsmXiNvMxiFQ== 71
0RCECvl47EJaiYvNp7GHYA== 72
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OKr/3PJN6FOO6xnhFAzW9w== 82
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VDhlIKghoLSbK3GJI3iREg== 86
S203+Ud/EhpNlvruXTNv3w== 87
NkyVsm2M/UcCGHX0ne1i3Q== 88
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CPiFazZNP6LHpOIK86vkzg== 90
CgttspQziSWrq4H7QqshlA== 91
MT/YfWKSquFvkRBLYLyciA== 92
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fuBEgx4H2U0Oy89TI4VgMQ== 95
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uSy3xXweQiQRTwOMcA2RJA== 97
lc7RHW8ew5KWJcZoJg1wuw== 98
s+kWyYo+xGfgjZ4FI8IuaA== 99
