diff --git a/crypto/crypto.go b/crypto/crypto.go
index 858b7a72a2..be1533b16d 100644
--- a/crypto/crypto.go
+++ b/crypto/crypto.go
@@ -350,13 +350,12 @@ func zeroBytes(bytes []byte) {
 	}
 }
 
-
-// for input read: https://github.com/ethereum/EIPs/issues/55
-// modelled after the JavaScript function toChecksumAddress()
-// Convert address into checksummed address
+// ChecksumAddress converts an address into a checksummed address.
+// It returns a 42-letter string starting with "0x".
+// The checksum algorithm is discussed in https://github.com/ethereum/EIPs/issues/55
 func ChecksumAddress(a common.Address) string {
-	address := strings.Replace(strings.ToLower(hex.EncodeToString(a.Bytes())), "0x", "", 1)
-	addressHash := hex.EncodeToString(Sha3([]byte(common.Bytes2Hex(a.Bytes()))))
+	address := hex.EncodeToString(a[:]) // hex.EncodeToString is always lower case without 0x prefix
+	addressHash := hex.EncodeToString(Sha3([]byte(common.Bytes2Hex(a[:]))))
 	checksumAddress := "0x"
 	for i := 0; i < len(address); i++ {
 		// If ith character is 8 to f then make it uppercase
@@ -370,8 +369,9 @@ func ChecksumAddress(a common.Address) string {
 	return checksumAddress
 }
 
-// Convert address in Hex format, with or without prefixed 0x into checksummed address
+// ChecksumAddressHex converts an address into a checksummed address.
+// The input s may or may not be prefixed with "0x".
+// The returned string is 42 long and always includes the prefix "0x".
 func ChecksumAddressHex(s string) string {
-	return ChecksumAddress(common.HexToAddress(strings.Replace(strings.ToLower(s), "0x", "", 1)))
+	return ChecksumAddress(common.HexToAddress(s))
 }
-
diff --git a/crypto/crypto_test.go b/crypto/crypto_test.go
index 86aedbec0b..24f6f9b958 100644
--- a/crypto/crypto_test.go
+++ b/crypto/crypto_test.go
@@ -26,7 +26,6 @@ import (
 	"os"
 	"testing"
 	"time"
-	"strings"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/crypto/secp256k1"
@@ -249,13 +248,10 @@ func TestPythonIntegration(t *testing.T) {
 	fmt.Printf("msg: %x, privkey: %x sig: %x\n", msg1, k1, sig1)
 }
 
-
+// TestChecksumAddress performs 4 groups of tests: a) all caps,
+// b) all lower, c) mixed lower and upper case, and
+// d) examples taken from myetherwallet.com
 func TestChecksumAddress(t *testing.T) {
-	// 4 groups of tests:
-	// All caps
-	// All lower
-	// Normal = mixed
-	// Taken from myetherwallet.com
 	testcases := []string{
 		"0x52908400098527886E0F7030069857D2E4169EE7",
 		"0x8617E340B3D01FA5F11F306F4090FD50E238070D",
@@ -289,8 +285,7 @@ func TestChecksumAddress(t *testing.T) {
 
 	failed, passed := 0, 0
 	for i := 0; i < len(testcases); i++ {
-		ba, _ := hex.DecodeString(strings.Replace(testcases[i], "0x", "", 1))
-		ca := ChecksumAddress(common.BytesToAddress(ba))
+		ca := ChecksumAddress(common.HexToAddress(testcases[i]))
 		if testcases[i] == ca {
 			passed++
 		} else {
@@ -386,4 +381,3 @@ func TestChecksumAddressHex(t *testing.T) {
 	}
 	fmt.Printf("Passed %d tests and failed %d tests out of %d.\n", passed, failed, passed+failed)
 }
-