added-hmac-sha-256-hashing

README.md

@@ -16,6 +16,7 @@ Easy-to-use, symmetric (AES-256) and asymmetric (RSA) encryption and also hash (
 * [How to add it to my project](#how-to-add-it-to-my-project)
 * [How to use? (Symmetric Encryption with AES)](#how-to-use-symmetric-encryption-with-aes)
 * [How to use? (Hash with SHA-256)](#how-to-use-hash-with-sha-256)
+* [How to use? (Hash with HMAC SHA-256)](#how-to-use-hash-with-hmac-sha-256)
 * [How to use? (Asymmetric Encryption with RSA)](#how-to-use-asymmetric-encryption-with-rsa)
 * [How do I generate Public/Private Keys?](#how-do-i-generate-publicprivate-keys)
 * [Relationship between key size and max text length that can be encrypted](#relationship-between-key-size-and-max-text-length-that-can-be-encrypted)
@@ -102,6 +103,29 @@ int main() {
 }
 ```
 
+## How to use? (Hash with HMAC SHA-256)
+
+All you need to do is call the **"hashWithHMACSHA256"** function to hash the given text by given secret key with HMAC SHA-256.
+
+```cpp
+#include "libcpp-crypto.hpp"
+
+using namespace lklibs;
+
+int main() {
+
+    auto plainText = "This text will be hashed soon";
+
+    const auto key = "mySecretKey";
+
+    const auto hashedText = CryptoService::hashWithHMACSHA256(plainText, key);
+
+    std::cout << "Hash: " << hashedText << std::endl;
+
+    return 0;
+}
+```
+
 ## How to use? (Asymmetric Encryption with RSA)
 
 To encrypt and decrypt the given text with RSA, all you need to do is call the **"encryptWithRSA"** and

examples/main.cpp

@@ -252,6 +252,16 @@ void hash()
     std::cout << "Hash: " << hashText << std::endl;
 }
 
+void hashWithHMACSHA256()
+{
+    const auto plainText = "This text will be hashed soon";
+    const auto key = "mySecretKey";
+
+    const auto hashText = CryptoService::hashWithHMACSHA256(plainText, key);
+
+    std::cout << "Hash: " << hashText << std::endl;
+}
+
 int main()
 {
     // Symmetric Encryption with AES
@@ -290,5 +300,7 @@ int main()
 
     hash();
 
+    hashWithHMACSHA256();
+
     return 0;
 }

src/libcpp-crypto.hpp

@@ -36,6 +36,7 @@ SOFTWARE.
 #include <openssl/aes.h>
 #include <openssl/pem.h>
 #include <openssl/rand.h>
+#include <openssl/hmac.h>
 #include <string>
 #include <cstring>
 #include <iomanip>
@@ -735,6 +736,43 @@ namespace lklibs
 
             return "";
         }
+
+        /**
+         * @brief Hashes the given string with HMAC SHA-256
+         *
+         * @param plainText String to hash
+         * @param key key to use for hashing plainText
+         *
+         * @return Hashed string
+         */
+        inline std::string hashWithHMACSHA256(const std::string& plainText, const std::string& key)
+        {
+            const auto keyBytes = reinterpret_cast<const unsigned char*>(key.c_str());
+            const size_t keyLength = key.length();
+
+            const auto data = reinterpret_cast<const unsigned char*>(plainText.c_str());
+            const size_t dataLength = plainText.length();
+
+            unsigned char result[SHA256_DIGEST_LENGTH];
+            unsigned int resultLength;
+
+            if (HMAC(EVP_sha256(), keyBytes, static_cast<int>(keyLength), data, static_cast<int>(dataLength), result, &resultLength) == nullptr)
+            {
+                std::cerr << "Error: HMAC calculation failed." << std::endl;
+
+                return "";
+            }
+
+            const std::vector hashBytes(result, result + resultLength);
+
+            std::stringstream ss;
+            for (const unsigned char byte : hashBytes)
+            {
+                ss << std::hex << std::setw(2) << std::setfill('0') << static_cast<int>(byte);
+            }
+
+            return ss.str();
+        }
     }
 }
 

test/test.cpp

@@ -494,6 +494,16 @@ TEST(HashTest, HashWithSHA256MustBeCompletedSuccessfully)
     ASSERT_EQ(hashText, "d32448bab2777b376a5592e384146c3c0182ba589e2521bd0275f2cef6a50546") << "Hash is invalid";
 }
 
+TEST(HmacSha256Test, HashWithHMACSHA256MustBeCompletedSuccessfully)
+{
+    const auto plainText = "This text will be hashed soon";
+    const auto key = "mySecretKey";
+
+    const auto hashText = CryptoService::hashWithHMACSHA256(plainText, key);
+
+    ASSERT_EQ(hashText, "875dae56af4cb9c9c1b2e7f30e28704da4f1933bf85bb180409761f9c4721186") << "Hash is invalid";
+}
+
 int main(int argc, char** argv)
 {
     testing::InitGoogleTest(&argc, argv);