Storing hash values from SHA256

Question

I am using this code and I can not save the output of the hash function to an array of char. Can you help me how to do that?

#include "sha256.h"
#include <Arduino.h>
#include "./printf.h"
void printHash(uint8_t* hash) {
 int i;
 for (i=0; i<32; i++) {
 Serial.print("0123456789abcdef"[hash[i]>>4]);
 Serial.print("0123456789abcdef"[hash[i]&0xf]);
 }
 Serial.println();
}
void setup()
{ String FinalStr="1234567890";
Sha256.init();
 Sha256.print(FinalStr);
 printHash(Sha256.result());
}
void loop()
{
}

• Jaromanda X: instead of printing it, put it in an array of char - you'll need an array 64 long of course
• Amr Ahmed: hello jaromanda,thank u for ur suggestion,i can not copy from the output of printhash function

Answer 1

This is the code that worked for me:

#include "sha256.h"
void setup(void)
{char encoded[64];
 Serial.begin(9600);
 // this is actually the RFC4231 4.3 test
 Sha256.init();
 Sha256.print("123");
 uint8_t * result = Sha256.result();
 Serial.println("Expect: 2d711642b726b04401627ca9fbac32f5c8530fb1903cc4db02258717921a4881");
 Serial.print( "Got : ");
 for (int i = 0; i < 32; i++) {
 Serial.print("0123456789abcdef"[result[i] >> 4]);
 Serial.print("0123456789abcdef"[result[i] & 0xf]);
 for(int i = 0; i < 64; i+=2)
 {
 encoded[i] = "0123456789abcdef"[result[i / 2] >> 4];
 encoded[i + 1] = "0123456789abcdef"[result[i / 2] & 0xf];
 }
 }
 Serial.print("\n");
 for(int z = 0; z < 64; z++)
 Serial.print(encoded[z]);
}
void loop(void)
{}

• Amr Ahmed: this is the code that worked for me

Answer 2

Save to a character vector (64 characters + NULL):

void copyHash(char* buf, uint8_t* hash) {
 int i, j = 0;
 for (i = 0; i < 32; i++) {
 buf[j++] = "0123456789abcdef"[hash[i]>>4];
 buf[j++] = "0123456789abcdef"[hash[i]&0xf];
 }
 buf[j] = 0;
}
void setup()
{ 
 String FinalStr="1234567890";
 Sha256.init();
 Sha256.print(FinalStr);
 char buf[65];
 copyHash(buf, Sha256.result());
}

Cheers!

• Amr Ahmed: hello mikael,thank u 4 ur help,i will try and tell u the results,deeply appreciated
• Amr Ahmed: I have tried and got different outputs "c775e7b757ede630cd0aa1113bd102661ab38829ca52a6422ab782862f268646 2f64612d9642afc666117f4d4fc87c17dba06ad091e1ce611f70020f2278337e"