1 Topic by rahmanikivi724 (edited by rahmanikivi724 2021-10-13 06:35:16)

  • Registered: 2021-10-08
  • Posts: 13

Topic: Diffrent digest in compare of Online hash fucntion

I used MD5 as a test function I fill buffer like this and used printf() and %x operator to show the content of md5sum and shaa256sum as a resualt.

buffer[1024]= "Hello";
MD5 is 
e358b60a19d79e6ec8ccc18c834425 
SHA is 
7040f8eeeddf088d9d42198f8cf33be1471b2c225af4c1ab496eab9b9a89f8

but it is a mistake because the Hash of Hello is this

Md5
8b1a9953c4611296a827abf8c47804d7
SHA256
185f8db32271fe25f561a6fc938b2e264306ec304eda518007d1764826381969

What thing would be my mistake?

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  • From: Mobile, AL
  • Registered: 2013-12-11
  • Posts: 357

Re: Diffrent digest in compare of Online hash fucntion

Hello

I would be curious to see your application code, perhaps you are hashing the whole buffer, not just the string "Hello"

wolfSSL has a command line utility project, aptly named wolfCLU:
https://github.com/wolfSSL/wolfCLU

I used it below to demonstrate that the hashes match the values from other tools (openssl and sha256sum):

$ echo "Hello" > test.txt
$ wolfssl -hash md5 -in test.txt 
09f7e02f1290be211da707a266f153b3
$ openssl md5 test.txt 
MD5(test.txt)= 09f7e02f1290be211da707a266f153b3
$ wolfssl -hash sha256 -in test.txt 
66a045b452102c59d840ec097d59d9467e13a3f34f6494e539ffd32c1bb35f18
$ sha256sum test.txt 
66a045b452102c59d840ec097d59d9467e13a3f34f6494e539ffd32c1bb35f18  test.txt

embhorn's Website

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  • Registered: 2021-10-08
  • Posts: 13

Re: Diffrent digest in compare of Online hash fucntion

this is my code 

byte md5sum[MD5_DIGEST_SIZE]; 
byte sha256sum[SHA256_DIGEST_SIZE]; 
byte buffer[1024]= "Hello"; 
Md5 md5;
Sha256 sha256;
//MD5
wc_InitMd5(&md5);
wc_Md5Update(&md5, buffer, sizeof(buffer)); 
wc_Md5Final(&md5, md5sum);
printf("MD5 is \n");
for(int i=0 ; i < MD5_DIGEST_SIZE ;i++)  printf("%x",md5sum[i]);
printf(" \n");
//SHA256
wc_InitSha256(&sha256);
wc_Sha256Update(&sha256, buffer, sizeof(buffer)); 
wc_Sha256Final(&sha256, sha256sum);
printf("SHA is \n");
for(int i=0 ; i < SHA256_DIGEST_SIZE  ;i++) printf("%x",sha256sum[i]);
printf(" \n");

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  • From: Mobile, AL
  • Registered: 2013-12-11
  • Posts: 357

Re: Diffrent digest in compare of Online hash fucntion

Yes, the sizeof operator returns the actual size of the buffer, not the string. You want to use 

 strlen(buffer)
#ifndef WOLFSSL_USER_SETTINGS
#include <wolfssl/options.h>
#endif
#include <wolfssl/wolfcrypt/settings.h>
#include <wolfssl/ssl.h>
#include <wolfssl/wolfcrypt/sha256.h>
#include <wolfssl/wolfcrypt/error-crypt.h>

void main() {
    byte md5sum[MD5_DIGEST_SIZE]; 
    byte sha256sum[SHA256_DIGEST_SIZE]; 
    byte buffer[1024] = "Hello";
    Md5 md5;
    Sha256 sha256;
    
    //MD5
    wc_InitMd5(&md5);
    wc_Md5Update(&md5, buffer, strlen(buffer));
    wc_Md5Final(&md5, md5sum);
    printf("MD5 is \n");
    for(int i=0 ; i < MD5_DIGEST_SIZE ;i++)  printf("%x",md5sum[i]);
        printf(" \n");
    wc_Md5Free(&md5);


    //SHA256
    wc_InitSha256(&sha256);
    wc_Sha256Update(&sha256, buffer, strlen(buffer));
    wc_Sha256Final(&sha256, sha256sum);
    printf("SHA is \n");
    for(int i=0 ; i < SHA256_DIGEST_SIZE  ;i++) printf("%x",sha256sum[i]);
        printf(" \n");
    wc_Sha256Free(&sha256);
}

MD5 is
8b1a9953c4611296a827abf8c4784d7
SHA is
185f8db32271fe25f561a6fc938b2e26436ec304eda51807d1764826381969

embhorn's Website

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  • Registered: 2021-10-08
  • Posts: 13

Re: Diffrent digest in compare of Online hash fucntion

Thanks for your help.It solved

I used this instructor because I found them in the manual CHAPTER 10: WOLFCRYPT USAGE REFERENCE
https://www.wolfssl.com/docs/wolfssl-manual/ch10/

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  • From: Mobile, AL
  • Registered: 2013-12-11
  • Posts: 357

Re: Diffrent digest in compare of Online hash fucntion

Excellent. Right, if you had filled the buffer with data (used all 1024 bytes), then the sizeof operator would be correct.

embhorn's Website

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