Databases
StackOverflow2013
Postsdbo
POOutput disappearing after half execution of main() in C
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POOutput disappearing after half execution of main() in C
    primarykey
    data
    text
    <p>I have a text file "my.txt". I want to read first 16 bytes from the text file and then perform the aes operation of key expansion and cipher algorithm on the data. After this, the next 16 bytes are to be encrypted. I run the following code but during execution, after entering the key in hexadecimal the output screen just disappears. I dont understand why is this so? Same work of file reading was successfully running in a separate program but after incorporating it into my AES (Advanced Encryption Standard) program, the file portion of the program does not execute. Infact the screen disappears after taking key from user. Please help me on this.</p> <pre><code> #include&lt;stdio.h&gt; #include&lt;stdlib.h&gt; #include&lt;conio.h&gt; #include&lt;string.h&gt; // The number of columns comprising a state in AES. This is a constant in AES. //Value=4 #define Nb 4 // The number of rounds in AES Cipher. It is simply initiated to zero. The actual value is recieved in the program. int Nr=0; // The number of 32 bit words in the key. It is simply initiated to zero. The actual value is recieved in the program. int Nk=0; // in - it is the array that holds the plain text to be encrypted. // out - it is the array that holds the output CipherText after encryption. // state - the array that holds the intermediate results during encryption. char in[64], out[16], state[4][4]; // The array that stores the round keys. char RoundKey[240]; // The Key input to the AES Program char Key[32]; int getSBoxValue(int num) { int sbox[256] = { //0 1 2 3 4 5 6 7 8 9 A B C D E F 0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76, //0 0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0, //1 0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15, //2 0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75, //3 0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84, //4 0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf, //5 0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8, //6 0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2, //7 0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73, //8 0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb, //9 0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79, //A 0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08, //B 0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a, //C 0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e, //D 0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf, //E 0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16 }; //F return sbox[num]; } // The round constant word array, Rcon[i], contains the values given by // x to th e power (i-1) being powers of x (x is denoted as {02}) in the field GF(28) // Note that i starts at 1, not 0). int Rcon[255] = { 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb }; // This function produces Nb(Nr+1) round keys. The round keys are used in each round to encrypt the states. void KeyExpansion() { int i,j; char temp[4],k; // The first round key is the key itself. for(i=0;i&lt;Nk;i++) { RoundKey[i*4]=Key[i*4]; RoundKey[i*4+1]=Key[i*4+1]; RoundKey[i*4+2]=Key[i*4+2]; RoundKey[i*4+3]=Key[i*4+3]; } // All other round keys are found from the previous round keys. while (i &lt; (Nb * (Nr+1))) { for(j=0;j&lt;4;j++) { temp[j]=RoundKey[(i-1) * 4 + j]; } if (i % Nk == 0) { // This function rotates the 4 bytes in a word to the left once. // [a0,a1,a2,a3] becomes [a1,a2,a3,a0] // Function RotWord() { k = temp[0]; temp[0] = temp[1]; temp[1] = temp[2]; temp[2] = temp[3]; temp[3] = k; } // SubWord() is a function that takes a four-byte input word and // applies the S-box to each of the four bytes to produce an output word. // Function Subword() { temp[0]=getSBoxValue(temp[0]); temp[1]=getSBoxValue(temp[1]); temp[2]=getSBoxValue(temp[2]); temp[3]=getSBoxValue(temp[3]); } temp[0] = temp[0] ^ Rcon[i/Nk]; } else if (Nk &gt; 6 &amp;&amp; i % Nk == 4) { // Function Subword() { temp[0]=getSBoxValue(temp[0]); temp[1]=getSBoxValue(temp[1]); temp[2]=getSBoxValue(temp[2]); temp[3]=getSBoxValue(temp[3]); } } RoundKey[i*4+0] = RoundKey[(i-Nk)*4+0] ^ temp[0]; RoundKey[i*4+1] = RoundKey[(i-Nk)*4+1] ^ temp[1]; RoundKey[i*4+2] = RoundKey[(i-Nk)*4+2] ^ temp[2]; RoundKey[i*4+3] = RoundKey[(i-Nk)*4+3] ^ temp[3]; i++; } } // This function adds the round key to state. // The round key is added to the state by an XOR function. void AddRoundKey(int round) { int i,j; for(i=0;i&lt;4;i++) { for(j=0;j&lt;4;j++) { state[j][i] ^= RoundKey[round * Nb * 4 + i * Nb + j]; } } } // The SubBytes Function Substitutes the values in the // state matrix with values in an S-box. void SubBytes() { int i,j; for(i=0;i&lt;4;i++) { for(j=0;j&lt;4;j++) { state[i][j] = getSBoxValue(state[i][j]); } } } // The ShiftRows() function shifts the rows in the state to the left. // Each row is shifted with different offset. // Offset = Row number. So the first row is not shifted. void ShiftRows() { char temp; // Rotate first row 1 columns to left temp=state[1][0]; state[1][0]=state[1][1]; state[1][1]=state[1][2]; state[1][2]=state[1][3]; state[1][3]=temp; // Rotate second row 2 columns to left temp=state[2][0]; state[2][0]=state[2][2]; state[2][2]=temp; temp=state[2][1]; state[2][1]=state[2][3]; state[2][3]=temp; // Rotate third row 3 columns to left temp=state[3][0]; state[3][0]=state[3][3]; state[3][3]=state[3][2]; state[3][2]=state[3][1]; state[3][1]=temp; } // xtime is a macro that finds the product of {02} and the argument to xtime modulo {1b} #define xtime(x) ((x&lt;&lt;1) ^ (((x&gt;&gt;7) &amp; 1) * 0x1b)) void MixColumns() { int i; char Tmp,Tm,t; for(i=0;i&lt;4;i++) { t=state[0][i]; Tmp = state[0][i] ^ state[1][i] ^ state[2][i] ^ state[3][i] ; Tm = state[0][i] ^ state[1][i] ; Tm = xtime(Tm); state[0][i] ^= Tm ^ Tmp ; Tm = state[1][i] ^ state[2][i] ; Tm = xtime(Tm); state[1][i] ^= Tm ^ Tmp ; Tm = state[2][i] ^ state[3][i] ; Tm = xtime(Tm); state[2][i] ^= Tm ^ Tmp ; Tm = state[3][i] ^ t ; Tm = xtime(Tm); state[3][i] ^= Tm ^ Tmp ; } } // Cipher is the main function that encrypts the PlainText. void Cipher() { int i,j,round=0; //Copy the input PlainText to state array. for(i=0;i&lt;4;i++) { for(j=0;j&lt;4;j++) { state[j][i] = in[i*4 + j]; } } // Add the First round key to the state before starting the rounds. AddRoundKey(0); // There will be Nr rounds. // The first Nr-1 rounds are identical. // These Nr-1 rounds are executed in the loop below. for(round=1;round&lt;Nr;round++) { SubBytes(); ShiftRows(); MixColumns(); AddRoundKey(round); } // The last round is given below. // The MixColumns function is not here in the last round. SubBytes(); ShiftRows(); AddRoundKey(Nr); // The encryption process is over. // Copy the state array to output array. for(i=0;i&lt;4;i++) { for(j=0;j&lt;4;j++) { out[i*4+j]=state[j][i]; } } } int main() { printf("\n*******************AES Encryption Implementation******************\n"); printf("\n******************************************************************\n"); int i; // Receive the length of key here. while(Nr!=128 &amp;&amp; Nr!=192 &amp;&amp; Nr!=256) { printf("\nEnter the length of Key (128, 192 or 256 only): "); scanf("%d",&amp;Nr); } // Calculate Nk and Nr from the received value. Nk = Nr / 32; Nr = Nk + 6; printf("\nEnter the Key in hexadecimal: \n"); for(i=0;i&lt;Nk*4;i++) { scanf("%x",&amp;Key[i]); } char ch, file_name[25]; FILE *fp; printf("Enter the name of file you wish to see\n"); gets(file_name); fp = fopen(file_name,"r"); // read mode if( fp == NULL ) { perror("Error while opening the file.\n"); exit(EXIT_FAILURE); } printf("The contents of %s file are :\n", file_name); char sig[64]; int j=0; int c; char *pstr=in; printf("The contents of %s file are :\n", file_name); for (i=1;i&lt;=(sizeof(sig)/16);i++) { while(j&lt;16*i) { fscanf(fp,"%c",&amp;sig[j]); sprintf(pstr,"%02x",sig[j]); sscanf(pstr,"%02x",&amp;in[j]); pstr+=2; printf("\nPlaintext:\n%02x ",in[j]); j++; } // The KeyExpansion routine must be called before encryption. KeyExpansion(); // The next function call encrypts the PlainText with the Key using AES algorithm. Cipher(); // Output the encrypted text. printf("\nText after encryption:\n"); for(c=0;c&lt;Nk*4;c++) { printf("\n%02x ",out[c]); } } fclose(fp); printf("\n\n"); getche(); } </code></pre>
    singulars
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PTQuestion
    1. USuser2503061
    1. USuser2503061
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. COYour code doesn't have proper includes and there are several mistakes ... run a debugger and you will get that .
      singulars
      1. POOutput disappearing after half execution of main() in C
      1. US0decimal0
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload