diff --git a/Implementierung/.gitignore b/Implementierung/.gitignore index 91f3d4d..d6dce6b 100644 --- a/Implementierung/.gitignore +++ b/Implementierung/.gitignore @@ -1,2 +1,3 @@ build -md2 \ No newline at end of file +md2 +testfile* \ No newline at end of file diff --git a/Implementierung/lib/md2_impls/md2_0.h b/Implementierung/lib/md2_impls/md2_0.h new file mode 100644 index 0000000..0b0172a --- /dev/null +++ b/Implementierung/lib/md2_impls/md2_0.h @@ -0,0 +1,14 @@ +#ifndef MD2_0_H +#define MD2_0_H + +#include +#include +#include +#include +#include +#include + +void md2_hash_0(size_t len, const uint8_t buf[], uint8_t out[16]); +void md2_checksum_0(size_t len, uint8_t* buf); + +#endif // MD2_0_H \ No newline at end of file diff --git a/Implementierung/lib/md2_impls/md2_common.h b/Implementierung/lib/md2_impls/md2_common.h new file mode 100644 index 0000000..f2b72c2 --- /dev/null +++ b/Implementierung/lib/md2_impls/md2_common.h @@ -0,0 +1,25 @@ +#ifndef MD2_COMMON_H +#define MD2_COMMON_H + +#include +#include +#include +#include +#include +#include + +/** + * @brief Some digits of pi + * + */ +extern unsigned char MD2_PI_SUBST[256]; + +/** + * @brief Print a buffer for debugging + * + * @param len length + * @param buf buffer + */ +void md2_print_buf(size_t len, uint8_t buf[len]); + +#endif // MD2_COMMON_H \ No newline at end of file diff --git a/Implementierung/src/md2_impls/md2_0.c b/Implementierung/src/md2_impls/md2_0.c new file mode 100644 index 0000000..0bf59a6 --- /dev/null +++ b/Implementierung/src/md2_impls/md2_0.c @@ -0,0 +1,75 @@ +#include "../../lib/md2_impls/md2_0.h" + +#include "../../lib/md2_impls/md2_common.h" + +void md2_checksum_0(size_t len, uint8_t* buf) { + uint8_t l = 0; + + for (int i = 0; i < len / 16; i++) { + for (int j = 0; j < 16; j++) { + u_int8_t c = buf[i * 16 + j]; + // reference is wrong. It says: Set C[j] to S[c xor L]. But it should be: + buf[len + j] ^= MD2_PI_SUBST[c ^ l]; + l = buf[len + j]; + } + } +} + +void md2_hash_0(size_t len, const uint8_t buf[len], uint8_t out[16]) { + // === step 1 === + int paddingNeeded = 16 - (len % 16); + uint8_t originalPadding = paddingNeeded; + len += paddingNeeded; + + // printf("len: %d\n", len); + + // +16 for the checksum + uint8_t* newBuf = calloc(len + 16, sizeof(uint8_t)); + // TODO: null check + memcpy(newBuf, buf, len - paddingNeeded); + + // printBuf(len + 16, newBuf); + + while (paddingNeeded > 0) { + newBuf[len - paddingNeeded] = originalPadding; + paddingNeeded--; + } + // printf("buf with padding: "); + // printBuf(len + 16, newBuf); + + // === step 2 === + md2_checksum_0(len, newBuf); + + // printf("buf with cecksum: "); + // printBuf(len + 16, newBuf); + + // === step 3 === + uint8_t* messageDigestBuf = calloc(48, sizeof(uint8_t)); + // TODO: add null check + + // === step 4 === + // <= because we need to hash the last block too + for (int i = 0; i <= (len + 16) / 16 - 1; i++) { + for (int j = 0; j < 16; j++) { + messageDigestBuf[16 + j] = newBuf[i * 16 + j]; + messageDigestBuf[32 + j] = + (messageDigestBuf[16 + j] ^ messageDigestBuf[j]); + } + + u_int8_t t = 0; + + for (int j = 0; j < 18; j++) { + for (int k = 0; k < 48; k++) { + t = messageDigestBuf[k] = messageDigestBuf[k] ^ MD2_PI_SUBST[t]; + } + t = (t + j) % 256; + } + } + // printf("messageDigestBuf: \n"); + // printBuf(16, messageDigestBuf); + + memcpy(out, messageDigestBuf, 16); + + free(messageDigestBuf); + free(newBuf); +} \ No newline at end of file diff --git a/Implementierung/src/md2_impls/md2_common.c b/Implementierung/src/md2_impls/md2_common.c new file mode 100644 index 0000000..6d2598d --- /dev/null +++ b/Implementierung/src/md2_impls/md2_common.c @@ -0,0 +1,29 @@ +#include "../../lib/md2_impls/md2_common.h" + +// Source: https://datatracker.ietf.org/doc/html/rfc1319 +unsigned char MD2_PI_SUBST[256] = { + 41, 46, 67, 201, 162, 216, 124, 1, 61, 54, 84, 161, 236, 240, 6, + 19, 98, 167, 5, 243, 192, 199, 115, 140, 152, 147, 43, 217, 188, 76, + 130, 202, 30, 155, 87, 60, 253, 212, 224, 22, 103, 66, 111, 24, 138, + 23, 229, 18, 190, 78, 196, 214, 218, 158, 222, 73, 160, 251, 245, 142, + 187, 47, 238, 122, 169, 104, 121, 145, 21, 178, 7, 63, 148, 194, 16, + 137, 11, 34, 95, 33, 128, 127, 93, 154, 90, 144, 50, 39, 53, 62, + 204, 231, 191, 247, 151, 3, 255, 25, 48, 179, 72, 165, 181, 209, 215, + 94, 146, 42, 172, 86, 170, 198, 79, 184, 56, 210, 150, 164, 125, 182, + 118, 252, 107, 226, 156, 116, 4, 241, 69, 157, 112, 89, 100, 113, 135, + 32, 134, 91, 207, 101, 230, 45, 168, 2, 27, 96, 37, 173, 174, 176, + 185, 246, 28, 70, 97, 105, 52, 64, 126, 15, 85, 71, 163, 35, 221, + 81, 175, 58, 195, 92, 249, 206, 186, 197, 234, 38, 44, 83, 13, 110, + 133, 40, 132, 9, 211, 223, 205, 244, 65, 129, 77, 82, 106, 220, 55, + 200, 108, 193, 171, 250, 36, 225, 123, 8, 12, 189, 177, 74, 120, 136, + 149, 139, 227, 99, 232, 109, 233, 203, 213, 254, 59, 0, 29, 57, 242, + 239, 183, 14, 102, 88, 208, 228, 166, 119, 114, 248, 235, 117, 75, 10, + 49, 68, 80, 180, 143, 237, 31, 26, 219, 153, 141, 51, 159, 17, 131, + 20}; + +void md2_print_buf(size_t len, uint8_t buf[len]) { + for (int i = 0; i < len; i++) { + printf("'%02x',", buf[i]); + } + printf("\n"); +} \ No newline at end of file diff --git a/Implementierung/testfile b/Implementierung/testfile deleted file mode 100644 index d72e1a3..0000000 Binary files a/Implementierung/testfile and /dev/null differ