diff --git a/include/chat/crypto.h b/include/chat/crypto.h
index 8f62225..bbbb8d1 100644
--- a/include/chat/crypto.h
+++ b/include/chat/crypto.h
@@ -46,7 +46,7 @@ why2_bool why2_chat_ecc_verify_signature(char *message, char *signature, EVP_PKE
 char *why2_chat_ecc_serialize_public_key(); //GET PUBLIC ECC KEY IN BASE64
 EVP_PKEY* why2_chat_ecc_deserialize_public_key(char *pubkey); //GET EVP_PKEY FROM BASE64 PUBLIC ECC KEY
 
-char *why2_sha256(char *input); //HASH input USING SHA256 AND RETURN IN STRING
+char *why2_sha256(char *input, size_t length); //HASH input USING SHA256 AND RETURN IN STRING
 
 #ifdef __cplusplus
 }
diff --git a/src/chat/crypto.c b/src/chat/crypto.c
index 76a8734..dc85750 100644
--- a/src/chat/crypto.c
+++ b/src/chat/crypto.c
@@ -247,12 +247,12 @@ void why2_chat_deallocate_keys(void)
     EVP_PKEY_free(keypair);
 }
 
-char *why2_sha256(char *input)
+char *why2_sha256(char *input, size_t length)
 {
     unsigned char *output = why2_malloc(SHA256_DIGEST_LENGTH + 1);
     char *formatted_output = why2_malloc(SHA256_DIGEST_LENGTH * 2 + 2);
 
-    SHA256((unsigned char*) input, strlen(input), output);
+    SHA256((unsigned char*) input, length, output);
 
     //SAVE AS STRING IN HEX
     for (int i = 0; i < SHA256_DIGEST_LENGTH; i++)