OpenSSL MD4 Hashing Example in C++

This tutorial will guide you on how to hash a string by using OpenSSL’s MD4 hash function. This tutorial will create two C++ example files which will compile and run in Ubuntu environment.

1. Here are the openssl MD4 sample source code.
   
   Example #1: md4_sample1.cpp
   C++

   #include <stdio.h> #include <string.h> #include <openssl/md4.h> int main() { unsigned char digest[MD4_DIGEST_LENGTH]; char string[] = "hello world"; MD4((unsigned char*)&string, strlen(string), (unsigned char*)&digest); char mdString[33]; for(int i = 0; i < MD4_DIGEST_LENGTH; i++) sprintf(&mdString[i*2], "%02x", (unsigned int)digest[i]); printf("md4 digest: %s\n", mdString); return 0; }

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   #include <stdio.h> #include <string.h> #include <openssl/md4.h>   int main() {     unsigned char digest[MD4_DIGEST_LENGTH];     char string[] = "hello world";          MD4((unsigned char*)&string, strlen(string), (unsigned char*)&digest);           char mdString[33];       for(int i = 0; i < MD4_DIGEST_LENGTH; i++)          sprintf(&mdString[i*2], "%02x", (unsigned int)digest[i]);       printf("md4 digest: %s\n", mdString);       return 0; }

   
   Example #2: md4_sample2.cpp

   C++

   #include <stdio.h> #include <string.h> #include <openssl/md4.h> int main() { unsigned char digest[MD4_DIGEST_LENGTH]; const char* string = "hello world"; MD4_CTX ctx; MD4_Init(&ctx); MD4_Update(&ctx, string, strlen(string)); MD4_Final(digest, &ctx); char mdString[33]; for (int i = 0; i < MD4_DIGEST_LENGTH; i++) sprintf(&mdString[i*2], "%02x", (unsigned int)digest[i]); printf("md4 digest: %s\n", mdString); return 0; }

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   #include <stdio.h> #include <string.h> #include <openssl/md4.h> int main() {     unsigned char digest[MD4_DIGEST_LENGTH];     const char* string = "hello world";       MD4_CTX ctx;     MD4_Init(&ctx);     MD4_Update(&ctx, string, strlen(string));     MD4_Final(digest, &ctx);       char mdString[33];     for (int i = 0; i < MD4_DIGEST_LENGTH; i++)         sprintf(&mdString[i*2], "%02x", (unsigned int)digest[i]);       printf("md4 digest: %s\n", mdString);         return 0; }

2. Let’s try to compile both sample cpp files and you should observe the following output screenshot.
   ~$ gcc md4_sample1.cpp -o sample1 -lcrypto
   ~$ ./sample1
   md4 digest: aa010fbc1d14c795d86ef98c9547d17
   ~$ gcc md4_sample2.cpp -o sample2 -lcrypto
   ~$ ./sample2
   md4 digest: aa010fbc1d14c795d86ef98c9547d17
   Note: -lcrypto will include the crypto library from openssl