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fix: everything

This commit is contained in:
Dorian Zedler 2022-06-29 18:29:26 +02:00
parent 0d3771c719
commit 9194475153
Signed by: dorian
GPG Key ID: 989DE36109AFA354
2 changed files with 20 additions and 16 deletions
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2
Implementierung/src/main.c
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@ -21,7 +21,7 @@ int main(int argc, char** argv) {
c.filename, c.implementationToUse, c.doBenchmark, c.benchmarkingCycles);
uint8_t out[16];
md2_hash(0, "", out);
md2_hash(3, "abc", out);
printf("Hash: ");
for (int i = 0; i < 16; i++) {

34
Implementierung/src/md2.c
View File

@ -26,7 +26,7 @@ static unsigned char PI_SUBST[256] = {
void printBuf(size_t len, uint8_t buf[len]) {
for (int i = 0; i < len; i++) {
printf("'%lx',", buf[i]);
printf("'%02x',", buf[i]);
}
printf("\n");
}
@ -37,42 +37,46 @@ void md2_checksum(size_t len, uint8_t* buf) {
for (int i = 0; i < len / 16; i++) {
for (int j = 0; j < 16; j++) {
u_int8_t c = buf[i * 16 + j];
buf[len + j] = PI_SUBST[c ^ l];
l = buf[len + j];
l = buf[len + j] = PI_SUBST[c ^ l];
}
}
}
void md2_hash(size_t len, const uint8_t buf[len], uint8_t out[16]) {
// add padding
// === step 1 ===
int paddingNeeded = 16 - (len % 16);
uint8_t originalPadding = paddingNeeded;
len += paddingNeeded;
printf("len: %d\n", len);
uint8_t* newBuf = calloc(len + 16, sizeof(uint8_t)); // +16 = Checksum
// +16 for the checksum
uint8_t* newBuf = calloc(len + 16, sizeof(uint8_t));
memcpy(newBuf, buf, len - paddingNeeded);
newBuf[4] = 'f';
while (paddingNeeded > 0) {
newBuf[len - paddingNeeded] = originalPadding;
paddingNeeded--;
}
printBuf(len, newBuf);
md2_checksum(len, newBuf);
printf("buf with padding: ");
printBuf(len + 16, newBuf);
// implement step 3
u_int8_t* messageDigestBuf = calloc(48, sizeof(uint8_t));
// === step 2 ===
md2_checksum(len, newBuf);
for (int i = 0; i <= len / 16;
i++) { // <= because we need to hash the last block too
printf("buf with cecksum: ");
printBuf(len + 16, newBuf);
// === step 3 ===
uint8_t* messageDigestBuf = calloc(48, sizeof(uint8_t));
// === 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] = (newBuf[16 + j] ^ messageDigestBuf[j]);
messageDigestBuf[32 + j] =
(messageDigestBuf[16 + j] ^ messageDigestBuf[j]);
}
u_int8_t t = 0;