Diff: rsa/rsa-slow.c

Revision:

10:e269fd7b9500

Parent:

2:82268409e83f

Child:

12:2c342345b3db

diff -r f354b4859b0b -r e269fd7b9500 rsa/rsa-slow.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rsa/rsa-slow.c	Tue Sep 24 18:11:02 2019 +0000
@@ -0,0 +1,93 @@
+#include <stdint.h>
+#include <stdbool.h>
+#include "rsa.h"
+#include "bignum.h"
+#include "hrtimer.h"
+#include "log.h"
+
+#define STATUS_NONE     0
+#define STATUS_STARTED  1
+#define STATUS_FINISHED 2
+
+#define MAX_COUNT 4
+
+static uint32_t m[MAX_COUNT][32];
+static uint32_t e[MAX_COUNT][32];
+static uint32_t n[MAX_COUNT][32];
+static uint32_t r[MAX_COUNT][32];
+
+static int status[MAX_COUNT];
+
+bool RsaSlowFinished(int slot)
+{
+    return status[slot] == STATUS_FINISHED;
+}
+
+uint32_t* RsaSlowResult(int slot)
+{
+    return r[slot];
+}
+void RsaSlowClear(int slot) //This is for security - call it as soon as you no longer need the result.
+{
+    status[slot] = STATUS_NONE;
+    BnZer1024(m[slot]);
+    BnZer1024(e[slot]);
+    BnZer1024(n[slot]);
+    BnZer1024(r[slot]);
+}
+int RsaSlowStart(uint32_t* message, uint32_t* exponent, uint32_t* modulus) //Returns the slot or -1 on failure - you must check!
+{
+    //If the exponent is empty then bomb out
+    if (BnIse1024(exponent))
+    {
+        LogTime("RsaSlowStart - empty exponent\r\n");
+        return -1;
+    }
+    
+    //Look for an empty slot
+    int slot = 0;
+    while (slot < MAX_COUNT)
+    {
+        if (status[slot] == STATUS_NONE) goto found;
+        slot++;
+    }
+    
+    //Look for a slot whch has been used and not cleared
+    slot = 0;
+    while (slot < MAX_COUNT)
+    {
+        if (status[slot] == STATUS_FINISHED) goto found;
+        slot++;
+    }
+    
+    //No available slot so bomb out
+    LogTimeF("RsaSlowStart - no available slots out of %d\r\n", MAX_COUNT);
+    return -1;
+    
+    //Start the calculation
+found:
+    BnModExpStart1024(m[slot], e[slot], n[slot], r[slot], message, exponent, modulus);
+    status[slot] = STATUS_STARTED;
+    return slot;
+}
+void RsaSlowMain()
+{
+    int slot = 0;
+    while (slot < MAX_COUNT)
+    {
+        if (status[slot] == STATUS_STARTED) goto found;
+        slot++;
+    }
+    return;
+    
+found:
+    ;
+    bool finished = BnModExpIterate1024(m[slot], e[slot], n[slot], r[slot]);
+
+    if (finished) status[slot] = STATUS_FINISHED;
+}
+
+void RsaSlowInit(void)
+{
+    for (int i = 0; i < MAX_COUNT; i++) status[i] = STATUS_NONE;
+}
\ No newline at end of file