first implementation of "pseudocode algorithm" (ms_corourke.pdf)

This commit is contained in:
Christoph Prüßner 2014-05-02 13:00:00 +02:00
parent 9cfb19ea78
commit ecdc32f5e0
2 changed files with 36 additions and 3 deletions

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@ -19,9 +19,27 @@
* MA 02110-1301 USA * MA 02110-1301 USA
*/ */
#include "ntru_decrypt.h"
/*
* Legend
*
* N : highest 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. // Require: N , q, p, secret key f , inverse polynomial Fp , and encrypted message e.
int ntru_decrypt(char *encr_msg, pb_poly *private_key, ntru_context *context, char ** decr_msg){ int ntru_decrypt(char *encr_msg, pb_poly *private_key, ntru_context *context, char ** decr_msg){
// StarMultiply(f, e, a, N, q) // toDo q = ?, p = ?, fp = ?
pb_poly *a = first_multiply(private_key, encr_msg, q);// StarMultiply(f, e, a, N, q)
for(int i = 0, i < N, i++){ for(int i = 0, i < N, i++){
if(a[i] < 0 ) { if(a[i] < 0 ) {
a[i] = a[i] + q; // Make all coefficients positive a[i] = a[i] + q; // Make all coefficients positive
@ -30,7 +48,20 @@ int ntru_decrypt(char *encr_msg, pb_poly *private_key, ntru_context *context, ch
a[i] = a[i] - q // Shift coefficients of a into range (q/2, q/2) a[i] = a[i] - q // Shift coefficients of a into range (q/2, q/2)
} }
} }
// StarMultiply(a, Fp , d, N, p) char* d = second_multiply(a, fp, p)// StarMultiply(a, Fp , d, N, p)
// {Decode returns the decrypted message, d, through the argument list.} // {Decode returns the decrypted message, d, through the argument list.}
return 0; return d;
}
// toDo fix header file definition and types if needed!
pb_poly* first_multiply(pb_poly *private_key, char *encr_msg, int q) {
// toDo a= f*e mod q
return NULL;
}
// toDo fix header file definition and types if needed!
char* second_multiply(pb_poly *a, pb_poly *fp, int p) {
//toDo a*Fp mod p
return NULL;
} }

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@ -26,5 +26,7 @@
#include "context.h" #include "context.h"
int ntru_decrypt(char *encr_msg, pb_poly *private_key, ntru_context *context, char ** decr_msg); int ntru_decrypt(char *encr_msg, pb_poly *private_key, ntru_context *context, char ** decr_msg);
pb_poly* first_multiply(pb_poly*, char*, int);
char* first_multiply(pb_poly*, pb_poly*, int);
#endif /* NTRU_DECRYPT */ #endif /* NTRU_DECRYPT */