1036.crypto columns

本文介绍了一种基于关键字排序的加密方法,通过特定的排序规则对字符串进行加密,并提供了实现该算法的C++代码示例。

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离散数学讲过这种加密的方法,其实就是关键字排序

一. 排序方法说明

先通过keyword,例如如果是BATBOY的话, 按照的先后顺序应该是104235, 也就是比如字符串是EYDEMBLRTHANMEKTETOEEOTH的话,首先因为keyword长度为6,所以排序的时候矩阵就是6列,行数是字符串的总数除以keyword的长度,此例中就是4*6矩阵.
首先对于给出的字符串先从第2列开始排,从下网上排,然后是排第一列,一次类推,直到排整个矩阵.
结果是:
MEETME
BYTHEO
LDOAKT
REENTH

然后按照从左到右的顺序输出就是所要的结果了.

//  离散数学讲过这种加密的方法,其实就是关键字排序
//  通过keyword先确定哪一行
#include<iostream>
#include<cstring>
using namespace std;

int main() {
  string keyword;
  string test;
  char ch[100][100];
  int sequence[100];
  int rows, columns;
  int temp;
  char tem;
  while (cin >> keyword && keyword != "THEEND") {
    cin >> test;
    columns = keyword.size();
    rows = (test.size() + columns - 1)/columns;
    for (int i = 0; i < columns; ++i)
      sequence[i] = i;
    for (int i = 0; i < columns - 1; ++i) {
      for (int j = columns - 1; j > 0; --j) {
        if (keyword[j] < keyword[j - 1]) {
          tem = keyword[j];
          keyword[j] = keyword[j - 1];
          keyword[j - 1] = tem;
          temp = sequence[j];
          sequence[j] = sequence[j - 1];
          sequence[j - 1] = temp;
        }
      }
    }
    int k = 0;
    for (int i = 0; i < columns; ++i)
      for (int j = 0; j < rows; ++j)
        ch[j][sequence[i]] = test[k++];
    for (int i = 0; i < rows; ++i) {
      for (int j = 0; j < columns; ++j) {
        cout << ch[i][j];
      }
    }
    cout << endl;
   }
  return 0;
 }
小结

这道题其实不是很难,主要是数组的重排问题,不过也是调试了蛮久,主要是一些细节问题要考虑清楚.

如下是对加密身份证的解密方法,请解读后提供在没有执行UTL_I18N和DBMS_CRYPTO权限,用纯 PL/SQL方法在oracle中怎么解密这部分被写入数据库的加密身份证号类似 293946034f99c0594c461b774d5cc361e8684945d9ee614ee283f59dfd2b9a25字符串: 方法: 加密:AesUtils.encode(cardNo) 解密:AesUtils.decode(cardNo) jar包内容: package com.lens.middle.common.util.codec; import com.lens.middle.common.util.lang.ExceptionUtils; import java.io.UnsupportedEncodingException; import java.security.GeneralSecurityException; import java.security.SecureRandom; import javax.crypto.Cipher; import javax.crypto.KeyGenerator; import javax.crypto.SecretKey; import javax.crypto.spec.IvParameterSpec; import javax.crypto.spec.SecretKeySpec; import org.apache.commons.lang3.StringUtils; public class AesUtils { private static final String AES = "AES"; private static final String AES_CBC = "AES/CBC/PKCS5Padding"; private static final int DEFAULT_AES_KEYSIZE = 128; private static final int DEFAULT_IVSIZE = 16; private static final SecureRandom RANDOM = new SecureRandom(); private static final String DEFAULT_URL_ENCODING = "UTF-8"; private static final byte[] DEFAULT_KEY = new byte[]{-97, 88, -94, 9, 70, -76, 126, 25, 0, 3, -20, 113, 108, 28, 69, 125}; public AesUtils() { } public static String genKeyString() { return EncodeUtils.encodeHex(genKey(128)); } public static String encode(String input) { try { return StringUtils.isEmpty(input) ? null : EncodeUtils.encodeHex(encode (input.getBytes("UTF-8"), DEFAULT_KEY)); } catch (UnsupportedEncodingException var2) { return ""; } } public static String encode(String input, String key) { try { return StringUtils.isEmpty(input) ? null : EncodeUtils.encodeHex(encode (input.getBytes("UTF-8"), EncodeUtils.decodeHex(key))); } catch (UnsupportedEncodingException var3) { return ""; } } public static String decode(String input) { try { return StringUtils.isEmpty(input) ? null : new String(decode (EncodeUtils.decodeHex(input), DEFAULT_KEY), "UTF-8"); } catch (UnsupportedEncodingException var2) { return ""; } } public static String decode(String input, String key) { try { return StringUtils.isEmpty(input) ? null : new String(decode (EncodeUtils.decodeHex(input), EncodeUtils.decodeHex(key)), "UTF-8"); } catch (UnsupportedEncodingException var3) { return ""; } } public static byte[] genKey() { return genKey(128); } public static byte[] genKey(int keysize) { try { KeyGenerator keyGenerator = KeyGenerator.getInstance("AES"); keyGenerator.init(keysize); SecretKey secretKey = keyGenerator.generateKey(); return secretKey.getEncoded(); } catch (GeneralSecurityException var3) { throw ExceptionUtils.unchecked(var3); } } public static byte[] genIV() { byte[] bytes = new byte[16]; RANDOM.nextBytes(bytes); return bytes; } public static byte[] encode(byte[] input, byte[] key) { return aes(input, key, 1); } public static byte[] encode(byte[] input, byte[] key, byte[] iv) { return aes(input, key, iv, 1); } public static byte[] decode(byte[] input, byte[] key) { return aes(input, key, 2); } public static byte[] decode(byte[] input, byte[] key, byte[] iv) { return aes(input, key, iv, 2); } private static byte[] aes(byte[] input, byte[] key, int mode) { try { SecretKey secretKey = new SecretKeySpec(key, "AES"); Cipher cipher = Cipher.getInstance("AES"); cipher.init(mode, secretKey); return cipher.doFinal(input); } catch (GeneralSecurityException var5) { throw ExceptionUtils.unchecked(var5); } } private static byte[] aes(byte[] input, byte[] key, byte[] iv, int mode) { try { SecretKey secretKey = new SecretKeySpec(key, "AES"); IvParameterSpec ivSpec = new IvParameterSpec(iv); Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding"); cipher.init(mode, secretKey, ivSpec); return cipher.doFinal(input); } catch (GeneralSecurityException var7) { throw ExceptionUtils.unchecked(var7); } } }
最新发布
08-13
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