Andrew Boyson / crypto

A simple library to support serving https.

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rsa/rsa-slow.c@12:2c342345b3db, 2019-09-26 (annotated)

Committer:
andrewboyson
Date:
Thu Sep 26 07:19:09 2019 +0000
Revision:
12:2c342345b3db
Parent:
10:e269fd7b9500 
Chinese remainder theorem implemented giving a useful reduction from 20s to 5s to decrypt RSA.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
andrewboyson 0:be515c9019e3 1 #include <stdint.h>
andrewboyson 0:be515c9019e3 2 #include <stdbool.h>
andrewboyson 10:e269fd7b9500 3 #include "rsa.h"
andrewboyson 0:be515c9019e3 4 #include "bignum.h"
andrewboyson 0:be515c9019e3 5 #include "hrtimer.h"
andrewboyson 2:82268409e83f 6 #include "log.h"
andrewboyson 0:be515c9019e3 7
andrewboyson 10:e269fd7b9500 8 #define STATUS_NONE 0
andrewboyson 10:e269fd7b9500 9 #define STATUS_STARTED 1
andrewboyson 10:e269fd7b9500 10 #define STATUS_FINISHED 2
andrewboyson 10:e269fd7b9500 11
andrewboyson 2:82268409e83f 12 #define MAX_COUNT 4
andrewboyson 2:82268409e83f 13
andrewboyson 2:82268409e83f 14 static uint32_t m[MAX_COUNT][32];
andrewboyson 2:82268409e83f 15 static uint32_t e[MAX_COUNT][32];
andrewboyson 2:82268409e83f 16 static uint32_t n[MAX_COUNT][32];
andrewboyson 2:82268409e83f 17 static uint32_t r[MAX_COUNT][32];
andrewboyson 2:82268409e83f 18
andrewboyson 10:e269fd7b9500 19 static int status[MAX_COUNT];
andrewboyson 0:be515c9019e3 20
andrewboyson 10:e269fd7b9500 21 bool RsaSlowFinished(int slot)
andrewboyson 10:e269fd7b9500 22 {
andrewboyson 10:e269fd7b9500 23 return status[slot] == STATUS_FINISHED;
andrewboyson 10:e269fd7b9500 24 }
andrewboyson 10:e269fd7b9500 25
andrewboyson 10:e269fd7b9500 26 uint32_t* RsaSlowResult(int slot)
andrewboyson 2:82268409e83f 27 {
andrewboyson 2:82268409e83f 28 return r[slot];
andrewboyson 2:82268409e83f 29 }
andrewboyson 10:e269fd7b9500 30 void RsaSlowClear(int slot) //This is for security - call it as soon as you no longer need the result.
andrewboyson 2:82268409e83f 31 {
andrewboyson 10:e269fd7b9500 32 status[slot] = STATUS_NONE;
andrewboyson 2:82268409e83f 33 BnZer1024(m[slot]);
andrewboyson 2:82268409e83f 34 BnZer1024(e[slot]);
andrewboyson 2:82268409e83f 35 BnZer1024(n[slot]);
andrewboyson 2:82268409e83f 36 BnZer1024(r[slot]);
andrewboyson 2:82268409e83f 37 }
andrewboyson 10:e269fd7b9500 38 int RsaSlowStart(uint32_t* message, uint32_t* exponent, uint32_t* modulus) //Returns the slot or -1 on failure - you must check!
andrewboyson 0:be515c9019e3 39 {
andrewboyson 2:82268409e83f 40 //If the exponent is empty then bomb out
andrewboyson 2:82268409e83f 41 if (BnIse1024(exponent))
andrewboyson 2:82268409e83f 42 {
andrewboyson 10:e269fd7b9500 43 LogTime("RsaSlowStart - empty exponent\r\n");
andrewboyson 2:82268409e83f 44 return -1;
andrewboyson 2:82268409e83f 45 }
andrewboyson 2:82268409e83f 46
andrewboyson 2:82268409e83f 47 //Look for an empty slot
andrewboyson 2:82268409e83f 48 int slot = 0;
andrewboyson 2:82268409e83f 49 while (slot < MAX_COUNT)
andrewboyson 2:82268409e83f 50 {
andrewboyson 10:e269fd7b9500 51 if (status[slot] == STATUS_NONE) goto found;
andrewboyson 2:82268409e83f 52 slot++;
andrewboyson 2:82268409e83f 53 }
andrewboyson 0:be515c9019e3 54
andrewboyson 2:82268409e83f 55 //Look for a slot whch has been used and not cleared
andrewboyson 2:82268409e83f 56 slot = 0;
andrewboyson 2:82268409e83f 57 while (slot < MAX_COUNT)
andrewboyson 2:82268409e83f 58 {
andrewboyson 10:e269fd7b9500 59 if (status[slot] == STATUS_FINISHED) goto found;
andrewboyson 2:82268409e83f 60 slot++;
andrewboyson 2:82268409e83f 61 }
andrewboyson 2:82268409e83f 62
andrewboyson 2:82268409e83f 63 //No available slot so bomb out
andrewboyson 10:e269fd7b9500 64 LogTimeF("RsaSlowStart - no available slots out of %d\r\n", MAX_COUNT);
andrewboyson 2:82268409e83f 65 return -1;
andrewboyson 2:82268409e83f 66
andrewboyson 2:82268409e83f 67 //Start the calculation
andrewboyson 2:82268409e83f 68 found:
andrewboyson 12:2c342345b3db 69 BnModExpStart1024(m[slot], e[slot], n[slot], r[slot], 1024, message, exponent, modulus);
andrewboyson 10:e269fd7b9500 70 status[slot] = STATUS_STARTED;
andrewboyson 2:82268409e83f 71 return slot;
andrewboyson 0:be515c9019e3 72 }
andrewboyson 10:e269fd7b9500 73 void RsaSlowMain()
andrewboyson 0:be515c9019e3 74 {
andrewboyson 2:82268409e83f 75 int slot = 0;
andrewboyson 2:82268409e83f 76 while (slot < MAX_COUNT)
andrewboyson 2:82268409e83f 77 {
andrewboyson 10:e269fd7b9500 78 if (status[slot] == STATUS_STARTED) goto found;
andrewboyson 2:82268409e83f 79 slot++;
andrewboyson 2:82268409e83f 80 }
andrewboyson 2:82268409e83f 81 return;
andrewboyson 2:82268409e83f 82
andrewboyson 2:82268409e83f 83 found:
andrewboyson 10:e269fd7b9500 84 ;
andrewboyson 10:e269fd7b9500 85 bool finished = BnModExpIterate1024(m[slot], e[slot], n[slot], r[slot]);
andrewboyson 10:e269fd7b9500 86
andrewboyson 10:e269fd7b9500 87 if (finished) status[slot] = STATUS_FINISHED;
andrewboyson 2:82268409e83f 88 }
andrewboyson 2:82268409e83f 89
andrewboyson 10:e269fd7b9500 90 void RsaSlowInit(void)
andrewboyson 2:82268409e83f 91 {
andrewboyson 10:e269fd7b9500 92 for (int i = 0; i < MAX_COUNT; i++) status[i] = STATUS_NONE;
andrewboyson 0:be515c9019e3 93 }