diff --git a/include/libeosio/WIF.hpp b/include/libeosio/WIF.hpp
index 1667283..9632a90 100644
--- a/include/libeosio/WIF.hpp
+++ b/include/libeosio/WIF.hpp
@@ -32,12 +32,12 @@ namespace libeosio {
 /**
  * Encode an EC private key to WIF String.
  */
-std::string wif_priv_encode(ec_privkey_t priv);
+std::string wif_priv_encode(const ec_privkey_t& priv);
 
 /**
  * Encode an EC public key to WIF String.
  */
-std::string wif_pub_encode(ec_pubkey_t pub, const std::string& prefix = "EOS");
+std::string wif_pub_encode(const ec_pubkey_t& pub, const std::string& prefix = "EOS");
 
 /**
  * Prints an EC keypair in WIF format to standard out.
diff --git a/src/WIF.cpp b/src/WIF.cpp
index fbbf2a7..3f2f94d 100644
--- a/src/WIF.cpp
+++ b/src/WIF.cpp
@@ -31,7 +31,7 @@ namespace libeosio {
 
 #define PRIV_KEY_PREFIX 0x80 /* 0x80 for "Bitcoin mainnet". Always used by EOS. */
 
-std::string wif_priv_encode(ec_privkey_t priv) {
+std::string wif_priv_encode(const ec_privkey_t& priv) {
 
 	checksum_t check;
 	// 1 byte extra for prefix.
@@ -46,7 +46,7 @@ std::string wif_priv_encode(ec_privkey_t priv) {
 	return base58_encode(buf, buf + sizeof(buf));
 }
 
-std::string wif_pub_encode(ec_pubkey_t pub, const std::string& prefix) {
+std::string wif_pub_encode(const ec_pubkey_t& pub, const std::string& prefix) {
 
 	checksum_t check = checksum_ripemd160(pub.data(), pub.size());
 	unsigned char buf[EC_PUBKEY_SIZE + CHECKSUM_SIZE];