diff --git a/src/crypto-support/crypto-helper.cpp b/src/crypto-support/crypto-helper.cpp
index 915dce2..76ae679 100644
--- a/src/crypto-support/crypto-helper.cpp
+++ b/src/crypto-support/crypto-helper.cpp
@@ -193,11 +193,11 @@
 int
 ndn_compute_hmac_sha256(const uint8_t* data, const unsigned data_length,
                         const uint8_t* key, const unsigned key_length,
-                        uint8_t* prk)
+                        uint8_t* result)
 {
   HMAC(EVP_sha256(), key, key_length,
        (unsigned char*)data, data_length,
-       (unsigned char*)prk, nullptr);
+       (unsigned char*)result, nullptr);
   return 0;
 }
 
@@ -374,48 +374,6 @@
   }
 }
 
-int
-hmac_sha_256(const uint8_t* key, size_t key_len,
-             const uint8_t* cleartext, size_t cleartext_len,
-             uint8_t* output, size_t* output_len)
-{
-    if (!key || !cleartext || !output) {
-        return -1;
-    }
-
-    auto private_key = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, nullptr, key, key_len);
-    auto hmac_context = EVP_MD_CTX_new();
-    if (!private_key || !hmac_context) {
-        handleErrors("Cannot create and initialise the context when calling HMAC_CTX_new()");
-        return -1;
-    }
-
-    if (EVP_DigestSignInit(hmac_context, nullptr, EVP_sha256(), nullptr, private_key) != 1) {
-        handleErrors("Cannot initialize DigestSign when calling EVP_DigestSignInit()");
-        EVP_MD_CTX_free(hmac_context);
-        EVP_PKEY_free(private_key);
-        return -1;
-    }
-
-    if (EVP_DigestSignUpdate(hmac_context, cleartext, cleartext_len) != 1) {
-        handleErrors("Cannot update DigestSign when calling EVP_DigestSignUpdate()");
-        EVP_MD_CTX_free(hmac_context);
-        EVP_PKEY_free(private_key);
-        return -1;
-    }
-
-    if (EVP_DigestSignFinal(hmac_context, output, output_len) != 1) {
-        handleErrors("Cannot finish DigestSign when calling EVP_DigestSignFinal()");
-        EVP_MD_CTX_free(hmac_context);
-        EVP_PKEY_free(private_key);
-        return -1;
-    }
-
-    EVP_MD_CTX_free(hmac_context);
-    EVP_PKEY_free(private_key);
-    return 0;
-}
-
 void
 handleErrors(const std::string& errorInfo)
 {
diff --git a/src/crypto-support/crypto-helper.hpp b/src/crypto-support/crypto-helper.hpp
index 88f1519..95879b3 100644
--- a/src/crypto-support/crypto-helper.hpp
+++ b/src/crypto-support/crypto-helper.hpp
@@ -69,10 +69,19 @@
      int saltLen, uint8_t* okm, int okm_len,
      const uint8_t* info = INFO, int info_len = INFO_LEN);
 
+/**
+ * HMAC SHA 256 keyed hash function
+ * @param key the key for the function
+ * @param key_len the length of the key
+ * @param data the array to hmac
+ * @param data_length the length of the array
+ * @param result result. Enough memory (32 Bytes) must be allocated beforehand
+ * @return 0 if successful, -1 if failed
+ */
 int
 ndn_compute_hmac_sha256(const uint8_t* data, const unsigned data_length,
                         const uint8_t* key, const unsigned key_length,
-                        uint8_t* prk);
+                        uint8_t* result);
 
 /**
  * Authentication GCM 128 Encryption