/* RC5REF.C -- Reference implementation of RC5-32/12/16 in C. */ /* Copyright (C) 1995 RSA Data Security, Inc. */ #include #include typedef unsigned long int WORD; /* Should be 32-bit = 4 bytes */ #define w 32 /* word size in bits */ // Brian's note: RFC-2040 defines word size as half the block size, so a 32-bit word is a 64-bit block #define r 12 /* number of rounds */ #define b 8 /* number of bytes in key */ // Brian's note: Adjusted key bytes to 8 from 16 #define c 2 /* number words in key = ceil(8*b/w)*/ // Brian's note: Adjusted this to 2 from 4 #define t 26 /* size of table S = 2*(r+1) words */ // Brian's note: adjusted thie to _ from 26 WORD S[t]; /* expanded key table */ WORD P = 0xb7e15163, Q = 0x9e3779b9; /* magic constants */ /* Rotation operators. x must be unsigned, to get logical right shift*/ #define ROTL(x,y) (((x)<<(y&(w-1))) | ((x)>>(w-(y&(w-1))))) #define ROTR(x,y) (((x)>>(y&(w-1))) | ((x)<<(w-(y&(w-1))))) unsigned char code[] = { 0x69,0xA9,0x3A,0xFD,0xC5,0xAD,0x43,0x8F,0x48,0x53,0x56,0x0F ,0x1D,0x35,0x3A,0x8C,0x5C,0x44,0xA6,0x90,0x1B,0x76,0x46,0xC7 ,0x65,0x53,0xC8,0xA1,0xE4,0xB0,0x40,0x41,0x85,0x2B,0xB7,0x81 ,0x59,0xE0,0xD2,0x39,0x35,0xA3,0x27,0x3B,0xC3,0xAF,0x2E,0x2E ,0x2F,0x3B,0x3B,0x0B,0x01,0xFE,0x67,0x51,0xFE,0x73,0xA8,0xE9 ,0x36,0x0A,0x93,0x85,0x55,0x2E,0x9A,0x4A,0xAE,0xC9,0x84,0xCF ,0x18,0xF8,0xAB,0x4D,0xB5,0x6D,0x45,0x07,0x4E,0x17,0x23,0xA5 ,0x7C,0xF1,0xE8,0xBD,0xA5,0x8A,0xBD,0xC8,0xFE,0xFC,0xDA,0x2B ,0x6B,0x71,0x76,0x88,0x1F,0xC0,0xD1,0x95,0x61,0x8D,0xDB,0xDC ,0xD8,0x17,0x2E,0xD7,0x1D,0xD5,0xF7,0xAB,0xAD,0xAB,0x3E,0x52 ,0x2A,0x9A,0x9B,0xBA,0x37,0xFE,0x80,0xFB,0x53,0x95,0xC9,0x1D ,0xA2,0x22,0xAE,0x72,0x85,0x4A,0x43,0x1F,0x7C,0x2A,0xBF,0x2A ,0x79,0x3A,0x15,0x03,0x8D,0xF2,0x5B,0x43,0x98,0x90,0x6D,0xCC ,0xA0,0xBB,0xE2,0xA9,0x6A,0x52,0xD1,0xCB,0x2B,0x83,0xDE,0xD8 ,0xBF,0xEC,0x20,0x11,0x70,0x71,0xAA,0x22 }; //void RC5_ENCRYPT(WORD *pt, WORD *ct) /* 2 WORD input pt/output ct */ //{ WORD i, A=pt[0]+S[0], B=pt[1]+S[1]; // for (i=1; i<=r; i++) // { A = ROTL(A^B,B)+S[2*i]; // B = ROTL(B^A,A)+S[2*i+1]; // } // ct[0] = A; ct[1] = B; //} void RC5_DECRYPT(WORD *ct, WORD *pt) /* 2 WORD input ct/output pt */ { WORD i, B=ct[1], A=ct[0]; for (i=r; i>0; i--) { B = ROTR(B-S[2*i+1],A)^A; A = ROTR(A-S[2*i],B)^B; } pt[1] = B-S[1]; pt[0] = A-S[0]; } void RC5_SETUP(unsigned char *K) /* secret input key K[0...b-1] */ { WORD i, j, k, u=w/8, A, B, L[c]; /* Initialize L, then S, then mix key into S */ for (i=b-1,L[c-1]=0; i!=-1; i--) L[i/u] = (L[i/u]<<8)+K[i]; for (S[0]=P,i=1; i 3*c */ { A = S[i] = ROTL(S[i]+(A+B),3); B = L[j] = ROTL(L[j]+(A+B),(A+B)); } } //void oldMain() //{ WORD i, j, pt1[2], pt2[2], ct[2] = {0,0}; // unsigned char key[b]; // if (sizeof(WORD)!=4) // printf("RC5 error: WORD has %d bytes.\n",sizeof(WORD)); // printf("RC5-32/12/16 examples:\n"); // for (i=1;i<6;i++) // { /* Initialize pt1 and key pseudorandomly based on previous ct */ // pt1[0]=ct[0]; pt1[1]=ct[1]; // for (j=0;j ciphertext %.8lX %.8lX \n", // pt1[0], pt1[1], ct[0], ct[1]); // if (pt1[0]!=pt2[0] || pt1[1]!=pt2[1]) // printf("Decryption Error!"); // } //} // Brute force key rotation void rotateKey(unsigned char *key, int len) { int i; int carry = 1; for (i=0; carry && (i '~') { carry = 1; key[i] = ' '; } } } // Key rotation using a dictionary file void rotateKey2(unsigned char *key, int len) { static FILE *f = NULL; char line[80]; if (f == NULL) { f = fopen("words.txt", "r"); } if (fgets(line, 80, f) == NULL) { // If EOF, just return the last expected key for the brute force, so the main program knows to exit memset(key, '~', len); }else{ memcpy(key, line, len); } } // Key rotation by brute force, using only uppercase, lowercase, and space void rotateKey3(unsigned char *key, int len) { int i; int carry = 1; for (i=0; carry && (i '~') { carry = 1; key[i] = ' '; } } } int main() { int i,j; int done; int binary; FILE *f; //unsigned char key[b] = {0x63,0xDE,0x7D,0xC1,0x54,0xF4,0xD0,0x39}; // RSA challenge key //unsigned char key[b] = {'P','e','r','p','l','e','x','C'}; // Obvious guess //unsigned char key[b] = {'p','e','r','p','l','e','x','c'}; // Obvious guess //unsigned char key[b] = {'P','E','R','P','L','E','X','C'}; // Different case //unsigned char key[b] = {'P','e','r','p','l','e','x',0x00}; // Obvious guess //unsigned char key[b] = {'p','e','r','p','l','e','x',0x00}; // Different case //unsigned char key[b] = {'P','E','R','P','L','E','X',0x00}; // Different case //unsigned char key[b] = {'T','h','i','r','t','e','e','n'}; // Guess from the card name because it's 8 letters //unsigned char key[b] = {'T','H','I','R','T','E','E','N'}; // Different case //unsigned char key[b] = {'t','h','i','r','t','e','e','n'}; // Different case //unsigned char key[b] = {0,0,0,0,0,0,0,0}; // No key //unsigned char key[b] = {'M','A','R','G','I','N','A','L'}; // Street name from back of card unsigned char key[b] = {' ',' ',' ',' ',' ',' ',' ',' '}; //unsigned char key[b] = {'I','?','$','+',' ',' ',' ',' '}; // <== where I left off during brute force key rotation unsigned char plaintext[8]; f = fopen("out.txt", "a"); fprintf(f, "========\n"); while (1) { binary = 0; printf("KEY: %c%c%c%c%c%c%c%c\n", key[0], key[1], key[2], key[3], key[4], key[5], key[6], key[7]); // Initialize vectors RC5_SETUP(key); //for (i=0; i '~') binary = 1; if ((plaintext[j] < ' ') && (plaintext[j] != '\r') && (plaintext[j] != '\n')) binary = 1; // Don't print the results for any answers to stdout // if ((plaintext[j] >= ' ') && (plaintext[j] <= '~')) { // printf("%c ", plaintext[j]); // } else { // printf("0x%02X ", plaintext[j]); // } } // If the decoded first block looks interesting, then save it to disk if (!binary) { fprintf(f, "KEY: %c%c%c%c%c%c%c%c\n", key[0], key[1], key[2], key[3], key[4], key[5], key[6], key[7]); fwrite(plaintext, 1, sizeof(plaintext), f); fprintf(f, "\n\n"); fwrite(plaintext, 1, sizeof(plaintext), stdout); printf("\n"); fflush(f); } //} // // Rotate using brute force // rotateKey(key, sizeof(key)); // Rotate using brute force (just letters) rotateKey3(key, sizeof(key)); // // Rotate using dictionary file // rotateKey2(key, sizeof(key)); done = 1; for (i=0; (i