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DOXYGEN: Documentation of ntru_decrypt function

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Removed unnecessary comments inside of function and wrote
a Doxygen compliant comment above the function
This commit is contained in:
Alexander Rolfes 2014-05-05 21:51:58 +02:00
parent eb83c04b93
commit dd73a662a0
1 changed files with 18 additions and 25 deletions
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41
src/ntru_decrypt.c
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@ -21,28 +21,28 @@
#include "ntru_decrypt.h"
/*
* Legend
*
* N : maximal degree of the polynom
* q : "is given" (... mod q)
* p : "is given" (... mod p)
* f : private key
* Fp: inverse of "modulo p"
* e : encrypted message
* a : result of first multiplication (StarMultiply(f, e, a, N, q))
* d : result of second multiplication (StarMultiply(a, Fp , d, N, p)), decrypted message
* */
// Require: N , q, p, secret key f , inverse polynomial Fp , and encrypted message e.
pb_poly* ntru_decrypt(pb_poly *encr_msg, pb_poly *private_key, pb_poly *Fp, ntru_context *context, char ** decr_msg){
/**
* Decryption of the given Polynom with the private key, its inverse
* and the fitting ntru_context
*
* @param encr_msg encrypted polynom with maximum length of N from
* the given context
* @param priv_key the polynom containing the private key to decrypt
* the message
* @param priv_key_inv the inverse polynome to the private key
* @param context the ntru_context
* @param decr_msg may contain the decrypted polynome at some point
* @returns the decrypted polynome at the moment
*
*
*/
unsigned int q = context->q;
unsigned int p = context->p;
unsigned int N = context->N;
unsigned int i;
// StarMultiply(f, e, a, N, q)
pb_poly *a = build_polynom(NULL, N, context);
pb_starmultiply(private_key, encr_msg, a, context, q);
@ -59,24 +59,17 @@ pb_poly* ntru_decrypt(pb_poly *encr_msg, pb_poly *private_key, pb_poly *Fp, ntru
mp_zero(&zero);
for(i = 0; i < N; i++){
if(mp_cmp(&(a->terms[i]),&zero) == MP_LT) { // Make all coefficients positive
//a->terms[i] = a->terms[i] + q;
if(mp_cmp(&(a->terms[i]),&zero) == MP_LT) {
mp_add((&a->terms[i]),&mp_q,(&a->terms[i]));
}
if(mp_cmp(&(a->terms[i]), &mp_qdiv2) == MP_GT) { // Shift coefficients of a into range (−q/2, q/2)
//a->terms[i] = a->terms[i] - mp_q;
if(mp_cmp(&(a->terms[i]), &mp_qdiv2) == MP_GT)
mp_sub((&a->terms[i]),&mp_q,(&a->terms[i]));
}
}
printf("%s\np:%d", "Nach dem StarMultiply: ", p);
draw_polynom(a);
pb_poly *d = build_polynom(NULL, N, context);
// StarMultiply(a, Fp , d, N, p)
pb_starmultiply(a, Fp, d, context, p);
// {Decode returns the decrypted message, d, through the argument list.}
return d;
}