From 7cc72ab3116899af56f2b898ce20448ab601eacd Mon Sep 17 00:00:00 2001 From: David Monniaux Date: Mon, 21 Jan 2019 21:44:54 +0100 Subject: DES --- test/monniaux/des/des.c | 500 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 500 insertions(+) create mode 100644 test/monniaux/des/des.c diff --git a/test/monniaux/des/des.c b/test/monniaux/des/des.c new file mode 100644 index 00000000..e8fae267 --- /dev/null +++ b/test/monniaux/des/des.c @@ -0,0 +1,500 @@ +#include +#include +#include + +typedef unsigned char ubyte; + +#define KEY_LEN 8 +typedef ubyte des_key_t[KEY_LEN]; + +const static ubyte PC1[] = { + 57, 49, 41, 33, 25, 17, 9, + 1, 58, 50, 42, 34, 26, 18, + 10, 2, 59, 51, 43, 35, 27, + 19, 11, 3, 60, 52, 44, 36, + 63, 55, 47, 39, 31, 23, 15, + 7, 62, 54, 46, 38, 30, 22, + 14, 6, 61, 53, 45, 37, 29, + 21, 13, 5, 28, 20, 12, 4 +}; + +const static ubyte PC2[] = { + 14, 17, 11, 24, 1, 5, + 3, 28, 15, 6, 21, 10, + 23, 19, 12, 4, 26, 8, + 16, 7, 27, 20, 13, 2, + 41, 52, 31, 37, 47, 55, + 30, 40, 51, 45, 33, 48, + 44, 49, 39, 56, 34, 53, + 46, 42, 50, 36, 29, 32 +}; + +const static ubyte IP[] = { + 58, 50, 42, 34, 26, 18, 10, 2, + 60, 52, 44, 36, 28, 20, 12, 4, + 62, 54, 46, 38, 30, 22, 14, 6, + 64, 56, 48, 40, 32, 24, 16, 8, + 57, 49, 41, 33, 25, 17, 9, 1, + 59, 51, 43, 35, 27, 19, 11, 3, + 61, 53, 45, 37, 29, 21, 13, 5, + 63, 55, 47, 39, 31, 23, 15, 7 +}; + +const static ubyte E[] = { + 32, 1, 2, 3, 4, 5, + 4, 5, 6, 7, 8, 9, + 8, 9, 10, 11, 12, 13, + 12, 13, 14, 15, 16, 17, + 16, 17, 18, 19, 20, 21, + 20, 21, 22, 23, 24, 25, + 24, 25, 26, 27, 28, 29, + 28, 29, 30, 31, 32, 1 +}; + +const static ubyte S[][64] = { + { + 14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7, + 0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8, + 4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0, + 15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13 + }, + { + 15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10, + 3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5, + 0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15, + 13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9 + }, + { + 10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8, + 13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1, + 13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7, + 1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12 + }, + { + 7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15, + 13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9, + 10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4, + 3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14 + }, + { + 2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9, + 14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6, + 4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14, + 11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3 + }, + { + 12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11, + 10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8, + 9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6, + 4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13 + }, + { + 4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1, + 13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6, + 1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2, + 6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12 + }, + { + 13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7, + 1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2, + 7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8, + 2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11 + } +}; + +const static ubyte P[] = { + 16, 7, 20, 21, + 29, 12, 28, 17, + 1, 15, 23, 26, + 5, 18, 31, 10, + 2, 8, 24, 14, + 32, 27, 3, 9, + 19, 13, 30, 6, + 22, 11, 4, 25 +}; + +const static ubyte IP2[] = { + 40, 8, 48, 16, 56, 24, 64, 32, + 39, 7, 47, 15, 55, 23, 63, 31, + 38, 6, 46, 14, 54, 22, 62, 30, + 37, 5, 45, 13, 53, 21, 61, 29, + 36, 4, 44, 12, 52, 20, 60, 28, + 35, 3, 43, 11, 51, 19, 59, 27, + 34, 2, 42, 10, 50, 18, 58, 26, + 33, 1, 41, 9, 49, 17, 57, 25 +}; + +const static ubyte SHIFTS[] = { + 1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1 +}; + +typedef struct { + ubyte *data; + int len; +} String; + +/* + * Transform a single nibble into a hex character + * + * in: a value < 0x10 + * + * returns: the character that represents the nibble + */ +static char toHex(ubyte in) { + if (0x00 <= in && in < 0x0A) { + return '0' + in; + } + if (0x0A <= in && in <= 0x0F) { + return 'A' + in - 0x0A; + } + return 0; +} + +/* + * Convert an array of bytes into a string + * + * ptr: the array of bytes + * len: the number of bytes + * out: a buffer allocated by the caller with enough space for 2*len+1 characters + */ +static void printBytes(const ubyte *ptr, int len, char *out) { + while (len-- > 0) { + *out++ = toHex(*ptr >> 4); + *out++ = toHex(*ptr & 0x0F); + + ptr++; + } + *out = 0; +} + +/* + * Gets the value of a bit in an array of bytes + * + * src: the array of bytes to index + * index: the desired bit to test the value of + * + * returns: the bit at the specified position in the array + */ +static int peekBit(const ubyte *src, int index) { + int cell = index / 8; + int bit = 7 - index % 8; + return (src[cell] & (1 << bit)) != 0; +} + +/* + * Sets the value of a bit in an array of bytes + * + * dst: the array of bits to set a bit in + * index: the position of the bit to set + * value: the value for the bit to set + */ +static void pokeBit(ubyte *dst, int index, int value) { + int cell = index / 8; + int bit = 7 - index % 8; + if (value == 0) { + dst[cell] &= ~(1 << bit); + } else { + dst[cell] |= (1 << bit); + } +} + +/* + * Transforms one array of bytes by shifting the bits the specified number of positions + * + * src: the array to shift bits from + * len: the length of the src array + * times: the number of positions that the bits should be shifted + * dst: a bytes array allocated by the caller to store the shifted values + */ +static void shiftLeft(const ubyte *src, int len, int times, ubyte *dst) { + int i, t; + for (i = 0; i <= len; ++i) { + pokeBit(dst, i, peekBit(src, i)); + } + for (t = 1; t <= times; ++t) { + int temp = peekBit(dst, 0); + for (i = 1; i <= len; ++i) { + pokeBit(dst, i - 1, peekBit(dst, i)); + } + pokeBit(dst, len - 1, temp); + } +} + +/* + * Calculates the sub keys to be used in processing the messages + * + * key: the array of bytes representing the key + * ks: the subkeys that have been allocated by the caller + */ +typedef ubyte subdes_key_t[17][6]; /* 17 sets of 48 bits */ +static void getSubKeys(const des_key_t key, subdes_key_t ks) { + ubyte c[17][7]; /* 56 bits */ + ubyte d[17][4]; /* 28 bits */ + ubyte kp[7]; + int i, j; + + /* intialize */ + memset(c, 0, sizeof(c)); + memset(d, 0, sizeof(d)); + memset(ks, 0, sizeof(subdes_key_t)); + + /* permute 'key' using table PC1 */ + for (i = 0; i < 56; ++i) { + pokeBit(kp, i, peekBit(key, PC1[i] - 1)); + } + + /* split 'kp' in half and process the resulting series of 'c' and 'd' */ + for (i = 0; i < 28; ++i) { + pokeBit(c[0], i, peekBit(kp, i)); + pokeBit(d[0], i, peekBit(kp, i + 28)); + } + + /* shift the components of c and d */ + for (i = 1; i < 17; ++i) { + shiftLeft(c[i - 1], 28, SHIFTS[i - 1], c[i]); + shiftLeft(d[i - 1], 28, SHIFTS[i - 1], d[i]); + } + + /* merge 'd' into 'c' */ + for (i = 1; i < 17; ++i) { + for (j = 28; j < 56; ++j) { + pokeBit(c[i], j, peekBit(d[i], j - 28)); + } + } + + /* form the sub-keys and store them in 'ks' + * permute 'c' using table PC2 */ + for (i = 1; i < 17; ++i) { + for (j = 0; j < 48; ++j) { + pokeBit(ks[i], j, peekBit(c[i], PC2[j] - 1)); + } + } +} + +/* + * Function used in processing the messages + * + * r: an array of bytes to be processed + * ks: one of the subkeys to be used for processing + * sp: output from the processing + */ +static void f(ubyte *r, ubyte *ks, ubyte *sp) { + ubyte er[6]; /* 48 bits */ + ubyte sr[4]; /* 32 bits */ + int i; + + /* initialize */ + memset(er, 0, sizeof(er)); + memset(sr, 0, sizeof(sr)); + + /* permute 'r' using table E */ + for (i = 0; i < 48; ++i) { + pokeBit(er, i, peekBit(r, E[i] - 1)); + } + + /* xor 'er' with 'ks' and store back into 'er' */ + for (i = 0; i < 6; ++i) { + er[i] ^= ks[i]; + } + + /* process 'er' six bits at a time and store resulting four bits in 'sr' */ + for (i = 0; i < 8; ++i) { + int j = i * 6; + int b[6]; + int k, row, col, m, n; + + for (k = 0; k < 6; ++k) { + b[k] = peekBit(er, j + k) != 0 ? 1 : 0; + } + + row = 2 * b[0] + b[5]; + col = 8 * b[1] + 4 * b[2] + 2 * b[3] + b[4]; + m = S[i][row * 16 + col]; /* apply table s */ + n = 1; + + while (m > 0) { + int p = m % 2; + pokeBit(sr, (i + 1) * 4 - n, p == 1); + m /= 2; + n++; + } + } + + /* permute sr using table P */ + for (i = 0; i < 32; ++i) { + pokeBit(sp, i, peekBit(sr, P[i] - 1)); + } +} + +/* + * Processing of block of the message + * + * message: an 8 byte block from the message + * ks: the subkeys to use in processing + * ep: space for an encoded 8 byte block allocated by the caller + */ +static void processMessage(const ubyte *message, subdes_key_t ks, ubyte *ep) { + ubyte left[17][4]; /* 32 bits */ + ubyte right[17][4]; /* 32 bits */ + ubyte mp[8]; /* 64 bits */ + ubyte e[8]; /* 64 bits */ + int i, j; + + /* permute 'message' using table IP */ + for (i = 0; i < 64; ++i) { + pokeBit(mp, i, peekBit(message, IP[i] - 1)); + } + + /* split 'mp' in half and process the resulting series of 'l' and 'r */ + for (i = 0; i < 32; ++i) { + pokeBit(left[0], i, peekBit(mp, i)); + pokeBit(right[0], i, peekBit(mp, i + 32)); + } + for (i = 1; i < 17; ++i) { + ubyte fs[4]; /* 32 bits */ + + memcpy(left[i], right[i - 1], 4); + f(right[i - 1], ks[i], fs); + for (j = 0; j < 4; ++j) { + left[i - 1][j] ^= fs[j]; + } + memcpy(right[i], left[i - 1], 4); + } + + /* amalgamate r[16] and l[16] (in that order) into 'e' */ + for (i = 0; i < 32; ++i) { + pokeBit(e, i, peekBit(right[16], i)); + } + for (i = 32; i < 64; ++i) { + pokeBit(e, i, peekBit(left[16], i - 32)); + } + + /* permute 'e' using table IP2 ad return result as a hex string */ + for (i = 0; i < 64; ++i) { + pokeBit(ep, i, peekBit(e, IP2[i] - 1)); + } +} + +/* + * Encrypts a message using DES + * + * key: the key to use to encrypt the message + * message: the message to be encrypted + * len: the length of the message + * + * returns: a paring of dynamically allocated memory for the encoded message, + * and the length of the encoded message. + * the caller will need to free the memory after use. + */ +String encrypt(const des_key_t key, const ubyte *message, int len) { + String result = { 0, 0 }; + subdes_key_t ks; + ubyte padByte; + int i; + + getSubKeys(key, ks); + + padByte = 8 - len % 8; + result.len = len + padByte; + result.data = (ubyte*)malloc(result.len); + memcpy(result.data, message, len); + memset(&result.data[len], padByte, padByte); + + for (i = 0; i < result.len; i += 8) { + processMessage(&result.data[i], ks, &result.data[i]); + } + + return result; +} + +/* + * Decrypts a message using DES + * + * key: the key to use to decrypt the message + * message: the message to be decrypted + * len: the length of the message + * + * returns: a paring of dynamically allocated memory for the decoded message, + * and the length of the decoded message. + * the caller will need to free the memory after use. + */ +String decrypt(const des_key_t key, const ubyte *message, int len) { + String result = { 0, 0 }; + subdes_key_t ks; + int i, j; + ubyte padByte; + + getSubKeys(key, ks); + /* reverse the subkeys */ + for (i = 1; i < 9; ++i) { + for (j = 0; j < 6; ++j) { + ubyte temp = ks[i][j]; + ks[i][j] = ks[17 - i][j]; + ks[17 - i][j] = temp; + } + } + + result.data = (ubyte*)malloc(len); + memcpy(result.data, message, len); + result.len = len; + for (i = 0; i < result.len; i += 8) { + processMessage(&result.data[i], ks, &result.data[i]); + } + + padByte = result.data[len - 1]; + result.len -= padByte; + return result; +} + +/* + * Convienience method for showing the round trip processing of a message + */ +void driver(const des_key_t key, const ubyte *message, int len) { + String encoded, decoded; + char buffer[128]; + + printBytes(key, KEY_LEN, buffer); + printf("Key : %s\n", buffer); + + printBytes(message, len, buffer); + printf("Message : %s\n", buffer); + + encoded = encrypt(key, message, len); + printBytes(encoded.data, encoded.len, buffer); + printf("Encoded : %s\n", buffer); + + decoded = decrypt(key, encoded.data, encoded.len); + printBytes(decoded.data, decoded.len, buffer); + printf("Decoded : %s\n\n", buffer); + + /* release allocated memory */ + if (encoded.len > 0) { + free(encoded.data); + encoded.data = 0; + } + if (decoded.len > 0) { + free(decoded.data); + decoded.data = 0; + } +} + +int main() { + const des_key_t keys[] = { + {0x13, 0x34, 0x57, 0x79, 0x9B, 0xBC, 0xDF, 0xF1}, + {0x0E, 0x32, 0x92, 0x32, 0xEA, 0x6D, 0x0D, 0x73}, + {0x0E, 0x32, 0x92, 0x32, 0xEA, 0x6D, 0x0D, 0x73} + }; + const ubyte message1[] = { 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF }; + const ubyte message2[] = { 0x87, 0x87, 0x87, 0x87, 0x87, 0x87, 0x87, 0x87 }; + const ubyte message3[] = { 0x59, 0x6F, 0x75, 0x72, 0x20, 0x6C, 0x69, 0x70, 0x73, 0x20, 0x61, 0x72, 0x65, 0x20, 0x73, 0x6D, 0x6F, 0x6F, 0x74, 0x68, 0x65, 0x72, 0x20, 0x74, 0x68, 0x61, 0x6E, 0x20, 0x76, 0x61, 0x73, 0x65, 0x6C, 0x69, 0x6E, 0x65, 0x0D, 0x0A }; + int len; + + len = sizeof(message1) / sizeof(ubyte); + driver(keys[0], message1, len); + + len = sizeof(message2) / sizeof(ubyte); + driver(keys[1], message2, len); + + len = sizeof(message3) / sizeof(ubyte); + driver(keys[2], message3, len); +} -- cgit