Cryptology by yaofenjin



 Tim Cahill
Ryan Church
          Project Progress
• We have researched hill ciphers and are in
  the process of understanding them.
• We are also in the process of writing one.

• We also have been researching the Da
  Vinci Code to see how cryptology is
                           Programming Example
•     Hill Cipher                                              while(i<ROW){
                                                                    scanf("%d", &A[i][j]);
#define ROW 3
                                                                    printf("%d ",A[i][j]);
#define COL 3
#define SIZE 3
int main()
  int i=0, j=0, A[ROW][COL], first, second, third;
  char sec[SIZE];
 printf("Enter your code: \n");

                                                                   first = ((sec[0]-'a')*A[0][0]+(sec[1]-'a')*A[1][0]+(sec[2]-
 while(i<SIZE){                                                          'a')*A[2][0])%26;
   sec[i]=getchar();                                               second =((sec[0]-'a')*A[0][1]+(sec[1]-'a')*A[1][1]+(sec[2]-
   printf("%c",sec[i]);                                                  'a')*A[2][1])%26;
   i++;                                                            third = ((sec[0]-'a')*A[0][2]+(sec[1]-'a')*A[1][2]+(sec[2]-
 }                                                                       'a')*A[2][2])%26;
 i=0;                                                              printf("The encrypted first letter is %d \n",first);
                                                                   printf("The encrypted second letter is %d \n",second);
 while(i<SIZE){                                                    printf("The encrypted third letter is %d \n",third);
   printf("%d ",sec[i]);                                           printf("\n");
 }                                                                 return 0;
 i=0;                                                          }

 printf("Now enter 9 numbers you wish to use as a key: \n");
                      Da Vinci Code
• Leonardo Da Vinci hid a lot of secrets in his paintings to protect
  certain things.

• For example: Evidently, Mona isn't quite the woman art historians
    thought she was. But only those who know the secret code can look at
    Leonardo da Vinci's famous portrait and see the happy hermaphrodite that
    lurks within.
•   He also made device called a cryptext which is a device with dials on it
    which need to be rotated properly in order to open it, but if someone tried
    to force it open the message inside would be destroyed.
Da Vinci Code (cont.)

           QuickTime™ an d a
     are need ed to see this picture .
         Summary of article
• Title- Spam and The Ongoing Battle For
  The Inbox.
• In this article a learning algorithm is used
  as a spam filter for security for all email
• This algorithm is so far advanced that it
  can detect key words such as money, free,
  and sex.
          Summary (cont.)
• The way this relates to cryptology is that
  the algorithm can determine a certain
  email is garbage and encrypt it so it
  doesn’t reach the email user.
• Although there are ways to get around the
  algorithms detection, only advanced
  spammers know the small tricks such as
  HTML coding or ASCII codes.
• Spam and the ongoing battle for the inbox.
  Communications of the ACM, Volume 50, #2 (2007), pages 24-33.
  Joshua Goodman, Gordon V. Cormack, David Heckerman.

• Textbook: Invitation to computer science java version
  Edition 3, Schneider, copyright 07. pages 600-607

• An overview of cryptography. Gary C. Kessler, may 1998 (23
  January 2009). (website)

  The Da Vinci Code:

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