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Fix the implementation of MDC-2. The state is chained as the key, not as the plaintext, through the block cipher

This commit is contained in:
Juhani Krekelä 2021-04-08 20:35:34 +03:00
parent d4b2d07c6e
commit 21ed995281
1 changed files with 24 additions and 24 deletions
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48
puer.c
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@ -130,36 +130,36 @@ void compress_hash(struct hashstate *state) {
message[2] = bytes2word(&state->buffer[8]);
message[3] = bytes2word(&state->buffer[12]);
// A_i, B_i
uint32_t a[4], b[4];
memcpy(a, state->a, sizeof(a));
memcpy(b, state->b, sizeof(b));
// V_i = M_i ^ E(M_i, A_i)
xxtea128(message, a);
a[0] ^= message[0];
a[1] ^= message[1];
a[2] ^= message[2];
a[3] ^= message[3];
// Note: In this description A_i is the *key*, not the plaintext
uint32_t v[4];
memcpy(v, message, sizeof(v));
xxtea128(state->a, v);
v[0] ^= message[0];
v[1] ^= message[1];
v[2] ^= message[2];
v[3] ^= message[3];
// W_i = M_i ^ E(M_i, B_i);
xxtea128(message, b);
b[0] ^= message[0];
b[1] ^= message[1];
b[2] ^= message[2];
b[3] ^= message[3];
uint32_t w[4];
memcpy(w, message, sizeof(w));
xxtea128(state->b, w);
w[0] ^= message[0];
w[1] ^= message[1];
w[2] ^= message[2];
w[3] ^= message[3];
// A_{i+1} = V_i^L || W_i^R
state->a[0] = a[0];
state->a[1] = a[1];
state->a[2] = b[2];
state->a[3] = b[3];
// A_{i+1} = Vwi^L || W_i^R
state->a[0] = v[0];
state->a[1] = v[1];
state->a[2] = w[2];
state->a[3] = w[3];
// B_{i+1} = W_i^L || V_i^R
state->b[0] = b[0];
state->b[1] = b[1];
state->b[2] = a[2];
state->b[3] = a[3];
state->b[0] = v[0];
state->b[1] = v[1];
state->b[2] = w[2];
state->b[3] = w[3];
// Mark that we have consumed the buffer
state->length = 0;