diff --git a/include/libeosio/checksum.hpp b/include/libeosio/checksum.hpp
index 6bedac9..376ca25 100644
--- a/include/libeosio/checksum.hpp
+++ b/include/libeosio/checksum.hpp
@@ -26,7 +26,6 @@
 
 #include <cstdint>
 #include <cstring>
-#include <array>
 #include <libeosio/hash.hpp>
 
 namespace libeosio {
@@ -39,7 +38,7 @@ namespace libeosio {
 /**
  * Checksum datatype
  */
-typedef std::array<unsigned char, CHECKSUM_SIZE> checksum_t;
+typedef unsigned char checksum_t[CHECKSUM_SIZE];
 
 /**
  * Checksum template function.
@@ -48,19 +47,18 @@ typedef std::array<unsigned char, CHECKSUM_SIZE> checksum_t;
  *  - F: Hash calculation function, should have the signature `T* F(const unsigned char *, std::size_t, T*)`
  */
 template <typename T, T* (*F)(const unsigned char *, std::size_t, T*)>
-inline checksum_t checksum(const unsigned char* data, std::size_t len) {
-	checksum_t crc;
+inline void checksum(const unsigned char* data, std::size_t len, checksum_t crc) {
 	T hash;
 
 	F(data, len, &hash);
-	std::memcpy(crc.data(), &hash, crc.size());
-	return crc;
+	std::memcpy(crc, &hash, CHECKSUM_SIZE);
 }
 
-template <checksum_t (*F)(const unsigned char *, std::size_t)>
+template <void (*F)(const unsigned char *, std::size_t, checksum_t)>
 inline bool checksum_validate(const unsigned char* data, std::size_t len) {
-	checksum_t check = F(data, len - CHECKSUM_SIZE);
-	return !memcmp(check.data(), data + (len - CHECKSUM_SIZE), CHECKSUM_SIZE);
+	checksum_t crc;
+	F(data, len - CHECKSUM_SIZE, crc);
+	return !memcmp(crc, data + (len - CHECKSUM_SIZE), CHECKSUM_SIZE);
 }
 
 /**
diff --git a/src/wif/k1.cpp b/src/wif/k1.cpp
index cb32283..fcabac5 100644
--- a/src/wif/k1.cpp
+++ b/src/wif/k1.cpp
@@ -33,28 +33,32 @@ namespace libeosio { namespace internal {
 // So this function is a quick hack to calculate it.
 //
 // Should implement and use Init/Update/Finalize hash functions to do it inplace.
-checksum_t _checksum_suffix(const unsigned char *in, size_t size, const char *suffix) {
+void _checksum_suffix(const unsigned char *in, size_t size, const char *suffix, checksum_t check) {
 	std::vector<unsigned char> buf(size + 2);
 
 	memcpy(buf.data(), in, size);
 	memcpy(buf.data() + size, suffix, 2);
 
-	return checksum_ripemd160(buf.data(), buf.size());
+	return checksum_ripemd160(buf.data(), buf.size(), (unsigned char*) check);
 }
 
 void pub_encoder_k1(const ec_pubkey_t& key, unsigned char *buf) {
 
-	checksum_t check = _checksum_suffix(key.data(), EC_PUBKEY_SIZE, "K1");
+	checksum_t check;
+
+	_checksum_suffix(key.data(), EC_PUBKEY_SIZE, "K1", check);
 
 	memcpy(buf, key.data(), EC_PUBKEY_SIZE);
-	memcpy(buf + EC_PUBKEY_SIZE, check.data(), check.size());
+	memcpy(buf + EC_PUBKEY_SIZE, check, CHECKSUM_SIZE);
 }
 
 bool pub_decoder_k1(const std::vector<unsigned char>& buf, ec_pubkey_t& key) {
 
-	checksum_t check = _checksum_suffix(buf.data(), EC_PUBKEY_SIZE, "K1");
+	checksum_t check;
 
-	if (memcmp(buf.data() + EC_PUBKEY_SIZE, check.data(), CHECKSUM_SIZE)) {
+	_checksum_suffix(buf.data(), EC_PUBKEY_SIZE, "K1", check);
+
+	if (memcmp(buf.data() + EC_PUBKEY_SIZE, check, CHECKSUM_SIZE)) {
 		return false;
 	}
 
@@ -63,10 +67,12 @@ bool pub_decoder_k1(const std::vector<unsigned char>& buf, ec_pubkey_t& key) {
 }
 
 size_t priv_encoder_k1(const ec_privkey_t& priv, unsigned char *buf) {
-	checksum_t check = _checksum_suffix(priv.data(), EC_PRIVKEY_SIZE, "K1");
+	checksum_t check;
+
+	_checksum_suffix(priv.data(), EC_PRIVKEY_SIZE, "K1", check);
 
 	memcpy(buf, priv.data(), priv.size());
-	memcpy(buf + EC_PRIVKEY_SIZE, check.data(), check.size());
+	memcpy(buf + EC_PRIVKEY_SIZE, check, CHECKSUM_SIZE);
 
 	return EC_PRIVKEY_SIZE + CHECKSUM_SIZE;
 }
@@ -77,8 +83,9 @@ bool priv_decoder_k1(const std::vector<unsigned char>& buf, ec_privkey_t& priv)
 		return false;
 	}
 
-	checksum_t check = _checksum_suffix(buf.data(), EC_PRIVKEY_SIZE, "K1");
-	if (memcmp(buf.data() + EC_PRIVKEY_SIZE, check.data(), CHECKSUM_SIZE)) {
+	checksum_t check;
+	_checksum_suffix(buf.data(), EC_PRIVKEY_SIZE, "K1", check);
+	if (memcmp(buf.data() + EC_PRIVKEY_SIZE, check, CHECKSUM_SIZE)) {
 		return false;
 	}
 
@@ -88,10 +95,12 @@ bool priv_decoder_k1(const std::vector<unsigned char>& buf, ec_privkey_t& priv)
 
 void sig_encoder_k1(const ec_signature_t& sig, unsigned char *buf) {
 
-	checksum_t check = _checksum_suffix(sig.data(), EC_SIGNATURE_SIZE, "K1");
+	checksum_t check;
+
+	_checksum_suffix(sig.data(), EC_SIGNATURE_SIZE, "K1", check);
 
 	memcpy(buf, sig.data(), sig.size());
-	memcpy(buf + EC_SIGNATURE_SIZE, check.data(), check.size());
+	memcpy(buf + EC_SIGNATURE_SIZE, check, CHECKSUM_SIZE);
 }
 
 bool sig_decoder_k1(const std::vector<unsigned char>& buf, ec_signature_t& sig) {
@@ -103,10 +112,10 @@ bool sig_decoder_k1(const std::vector<unsigned char>& buf, ec_signature_t& sig)
 	}
 
 	// Calculate checksum
-	check = _checksum_suffix(buf.data(), EC_SIGNATURE_SIZE, "K1");
+	_checksum_suffix(buf.data(), EC_SIGNATURE_SIZE, "K1", check);
 
 	// And validate
-	if (memcmp(buf.data() + EC_SIGNATURE_SIZE, check.data(), CHECKSUM_SIZE)) {
+	if (memcmp(buf.data() + EC_SIGNATURE_SIZE, check, CHECKSUM_SIZE)) {
 		return false;
 	}
 
diff --git a/src/wif/legacy.cpp b/src/wif/legacy.cpp
index 96578e6..aca47a7 100644
--- a/src/wif/legacy.cpp
+++ b/src/wif/legacy.cpp
@@ -31,10 +31,12 @@ namespace libeosio { namespace internal {
 
 void pub_encoder_legacy(const ec_pubkey_t& key, unsigned char *buf) {
 
-	checksum_t check = checksum_ripemd160(key.data(), EC_PUBKEY_SIZE);
+	checksum_t check;
+
+	checksum_ripemd160(key.data(), EC_PUBKEY_SIZE, check);
 
 	memcpy(buf, key.data(), EC_PUBKEY_SIZE);
-	memcpy(buf + EC_PUBKEY_SIZE, check.data(), check.size());
+	memcpy(buf + EC_PUBKEY_SIZE, check, CHECKSUM_SIZE);
 }
 
 bool pub_decoder_legacy(const std::vector<unsigned char>& buf, ec_pubkey_t& key) {
@@ -52,8 +54,8 @@ size_t priv_encoder_legacy(const ec_privkey_t& priv, unsigned char *buf) {
 
 	buf[0] = PRIV_KEY_PREFIX;
 	memcpy(buf + 1, priv.data(), EC_PRIVKEY_SIZE);
-	check = checksum_sha256d(buf, 1 + EC_PRIVKEY_SIZE);
-	memcpy(buf + 1 + EC_PRIVKEY_SIZE, check.data(), check.size());
+	checksum_sha256d(buf, 1 + EC_PRIVKEY_SIZE, check);
+	memcpy(buf + 1 + EC_PRIVKEY_SIZE, check, CHECKSUM_SIZE);
 
 	return 1 + EC_PRIVKEY_SIZE + CHECKSUM_SIZE;
 }