diff --git a/rtc_base/string_encode.cc b/rtc_base/string_encode.cc
index 85c7a3f..7b2eda7 100644
--- a/rtc_base/string_encode.cc
+++ b/rtc_base/string_encode.cc
@@ -22,13 +22,16 @@
 // String Encoding Utilities
 /////////////////////////////////////////////////////////////////////////////
 
-static const char HEX[] = "0123456789abcdef";
+namespace {
+const char HEX[] = "0123456789abcdef";
 
+// Convert an unsigned value from 0 to 15 to the hex character equivalent...
 char hex_encode(unsigned char val) {
   RTC_DCHECK_LT(val, 16);
   return (val < 16) ? HEX[val] : '!';
 }
 
+// ...and vice-versa.
 bool hex_decode(char ch, unsigned char* val) {
   if ((ch >= '0') && (ch <= '9')) {
     *val = ch - '0';
@@ -42,13 +45,9 @@
   return true;
 }
 
-size_t hex_encode(char* buffer,
-                  size_t buflen,
-                  const char* csource,
-                  size_t srclen) {
-  return hex_encode_with_delimiter(buffer, buflen, csource, srclen, 0);
-}
-
+// hex_encode, but separate each byte representation with a delimiter.
+// |delimiter| == 0 means no delimiter
+// If the buffer is too short, we return 0
 size_t hex_encode_with_delimiter(char* buffer,
                                  size_t buflen,
                                  const char* csource,
@@ -84,6 +83,8 @@
   return bufpos;
 }
 
+}  // namespace
+
 std::string hex_encode(const std::string& str) {
   return hex_encode(str.c_str(), str.size());
 }
diff --git a/rtc_base/string_encode.h b/rtc_base/string_encode.h
index d0f323d..2ea09e2 100644
--- a/rtc_base/string_encode.h
+++ b/rtc_base/string_encode.h
@@ -26,27 +26,6 @@
 // String Encoding Utilities
 //////////////////////////////////////////////////////////////////////
 
-// Convert an unsigned value from 0 to 15 to the hex character equivalent...
-char hex_encode(unsigned char val);
-// ...and vice-versa.
-bool hex_decode(char ch, unsigned char* val);
-
-// hex_encode shows the hex representation of binary data in ascii.
-size_t hex_encode(char* buffer,
-                  size_t buflen,
-                  const char* source,
-                  size_t srclen);
-
-// hex_encode, but separate each byte representation with a delimiter.
-// |delimiter| == 0 means no delimiter
-// If the buffer is too short, we return 0
-size_t hex_encode_with_delimiter(char* buffer,
-                                 size_t buflen,
-                                 const char* source,
-                                 size_t srclen,
-                                 char delimiter);
-
-// Helper functions for hex_encode.
 std::string hex_encode(const std::string& str);
 std::string hex_encode(const char* source, size_t srclen);
 std::string hex_encode_with_delimiter(const char* source,
diff --git a/rtc_base/string_encode_unittest.cc b/rtc_base/string_encode_unittest.cc
index d4fe2c5..4854299 100644
--- a/rtc_base/string_encode_unittest.cc
+++ b/rtc_base/string_encode_unittest.cc
@@ -19,7 +19,7 @@
 
 class HexEncodeTest : public ::testing::Test {
  public:
-  HexEncodeTest() : enc_res_(0), dec_res_(0) {
+  HexEncodeTest() : dec_res_(0) {
     for (size_t i = 0; i < sizeof(data_); ++i) {
       data_[i] = (i + 128) & 0xff;
     }
@@ -27,111 +27,74 @@
   }
 
   char data_[10];
-  char encoded_[31];
   char decoded_[11];
-  size_t enc_res_;
   size_t dec_res_;
 };
 
 // Test that we can convert to/from hex with no delimiter.
 TEST_F(HexEncodeTest, TestWithNoDelimiter) {
-  enc_res_ = hex_encode(encoded_, sizeof(encoded_), data_, sizeof(data_));
-  ASSERT_EQ(sizeof(data_) * 2, enc_res_);
-  ASSERT_STREQ("80818283848586878889", encoded_);
-  dec_res_ = hex_decode(decoded_, sizeof(decoded_), encoded_, enc_res_);
+  std::string encoded = hex_encode(data_, sizeof(data_));
+  EXPECT_EQ("80818283848586878889", encoded);
+  dec_res_ =
+      hex_decode(decoded_, sizeof(decoded_), encoded.data(), encoded.size());
   ASSERT_EQ(sizeof(data_), dec_res_);
   ASSERT_EQ(0, memcmp(data_, decoded_, dec_res_));
 }
 
 // Test that we can convert to/from hex with a colon delimiter.
 TEST_F(HexEncodeTest, TestWithDelimiter) {
-  enc_res_ = hex_encode_with_delimiter(encoded_, sizeof(encoded_), data_,
-                                       sizeof(data_), ':');
-  ASSERT_EQ(sizeof(data_) * 3 - 1, enc_res_);
-  ASSERT_STREQ("80:81:82:83:84:85:86:87:88:89", encoded_);
-  dec_res_ = hex_decode_with_delimiter(decoded_, sizeof(decoded_), encoded_,
-                                       enc_res_, ':');
+  std::string encoded = hex_encode_with_delimiter(data_, sizeof(data_), ':');
+  EXPECT_EQ("80:81:82:83:84:85:86:87:88:89", encoded);
+  dec_res_ = hex_decode_with_delimiter(decoded_, sizeof(decoded_),
+                                       encoded.data(), encoded.size(), ':');
   ASSERT_EQ(sizeof(data_), dec_res_);
   ASSERT_EQ(0, memcmp(data_, decoded_, dec_res_));
 }
 
 // Test that encoding with one delimiter and decoding with another fails.
 TEST_F(HexEncodeTest, TestWithWrongDelimiter) {
-  enc_res_ = hex_encode_with_delimiter(encoded_, sizeof(encoded_), data_,
-                                       sizeof(data_), ':');
-  ASSERT_EQ(sizeof(data_) * 3 - 1, enc_res_);
-  dec_res_ = hex_decode_with_delimiter(decoded_, sizeof(decoded_), encoded_,
-                                       enc_res_, '/');
+  std::string encoded = hex_encode_with_delimiter(data_, sizeof(data_), ':');
+  dec_res_ = hex_decode_with_delimiter(decoded_, sizeof(decoded_),
+                                       encoded.data(), encoded.size(), '/');
   ASSERT_EQ(0U, dec_res_);
 }
 
 // Test that encoding without a delimiter and decoding with one fails.
 TEST_F(HexEncodeTest, TestExpectedDelimiter) {
-  enc_res_ = hex_encode(encoded_, sizeof(encoded_), data_, sizeof(data_));
-  ASSERT_EQ(sizeof(data_) * 2, enc_res_);
-  dec_res_ = hex_decode_with_delimiter(decoded_, sizeof(decoded_), encoded_,
-                                       enc_res_, ':');
+  std::string encoded = hex_encode(data_, sizeof(data_));
+  EXPECT_EQ(sizeof(data_) * 2, encoded.size());
+  dec_res_ = hex_decode_with_delimiter(decoded_, sizeof(decoded_),
+                                       encoded.data(), encoded.size(), ':');
   ASSERT_EQ(0U, dec_res_);
 }
 
 // Test that encoding with a delimiter and decoding without one fails.
 TEST_F(HexEncodeTest, TestExpectedNoDelimiter) {
-  enc_res_ = hex_encode_with_delimiter(encoded_, sizeof(encoded_), data_,
-                                       sizeof(data_), ':');
-  ASSERT_EQ(sizeof(data_) * 3 - 1, enc_res_);
-  dec_res_ = hex_decode(decoded_, sizeof(decoded_), encoded_, enc_res_);
+  std::string encoded = hex_encode_with_delimiter(data_, sizeof(data_), ':');
+  EXPECT_EQ(sizeof(data_) * 3 - 1, encoded.size());
+  dec_res_ =
+      hex_decode(decoded_, sizeof(decoded_), encoded.data(), encoded.size());
   ASSERT_EQ(0U, dec_res_);
 }
 
 // Test that we handle a zero-length buffer with no delimiter.
 TEST_F(HexEncodeTest, TestZeroLengthNoDelimiter) {
-  enc_res_ = hex_encode(encoded_, sizeof(encoded_), "", 0);
-  ASSERT_EQ(0U, enc_res_);
-  dec_res_ = hex_decode(decoded_, sizeof(decoded_), encoded_, enc_res_);
+  std::string encoded = hex_encode("", 0);
+  EXPECT_TRUE(encoded.empty());
+  dec_res_ =
+      hex_decode(decoded_, sizeof(decoded_), encoded.data(), encoded.size());
   ASSERT_EQ(0U, dec_res_);
 }
 
 // Test that we handle a zero-length buffer with a delimiter.
 TEST_F(HexEncodeTest, TestZeroLengthWithDelimiter) {
-  enc_res_ = hex_encode_with_delimiter(encoded_, sizeof(encoded_), "", 0, ':');
-  ASSERT_EQ(0U, enc_res_);
-  dec_res_ = hex_decode_with_delimiter(decoded_, sizeof(decoded_), encoded_,
-                                       enc_res_, ':');
+  std::string encoded = hex_encode_with_delimiter("", 0, ':');
+  EXPECT_TRUE(encoded.empty());
+  dec_res_ = hex_decode_with_delimiter(decoded_, sizeof(decoded_),
+                                       encoded.data(), encoded.size(), ':');
   ASSERT_EQ(0U, dec_res_);
 }
 
-// Test the std::string variants that take no delimiter.
-TEST_F(HexEncodeTest, TestHelpersNoDelimiter) {
-  std::string result = hex_encode(data_, sizeof(data_));
-  ASSERT_EQ("80818283848586878889", result);
-  dec_res_ = hex_decode(decoded_, sizeof(decoded_), result);
-  ASSERT_EQ(sizeof(data_), dec_res_);
-  ASSERT_EQ(0, memcmp(data_, decoded_, dec_res_));
-}
-
-// Test the std::string variants that use a delimiter.
-TEST_F(HexEncodeTest, TestHelpersWithDelimiter) {
-  std::string result = hex_encode_with_delimiter(data_, sizeof(data_), ':');
-  ASSERT_EQ("80:81:82:83:84:85:86:87:88:89", result);
-  dec_res_ = hex_decode_with_delimiter(decoded_, sizeof(decoded_), result, ':');
-  ASSERT_EQ(sizeof(data_), dec_res_);
-  ASSERT_EQ(0, memcmp(data_, decoded_, dec_res_));
-}
-
-// Test that encoding into a too-small output buffer (without delimiter) fails.
-TEST_F(HexEncodeTest, TestEncodeTooShort) {
-  enc_res_ = hex_encode_with_delimiter(encoded_, sizeof(data_) * 2, data_,
-                                       sizeof(data_), 0);
-  ASSERT_EQ(0U, enc_res_);
-}
-
-// Test that encoding into a too-small output buffer (with delimiter) fails.
-TEST_F(HexEncodeTest, TestEncodeWithDelimiterTooShort) {
-  enc_res_ = hex_encode_with_delimiter(encoded_, sizeof(data_) * 3 - 1, data_,
-                                       sizeof(data_), ':');
-  ASSERT_EQ(0U, enc_res_);
-}
-
 // Test that decoding into a too-small output buffer fails.
 TEST_F(HexEncodeTest, TestDecodeTooShort) {
   dec_res_ = hex_decode_with_delimiter(decoded_, 4, "0123456789", 10, 0);