diff --git a/src/pubkey.h b/src/pubkey.h
index 193b4667ab..c2aa851725 100644
--- a/src/pubkey.h
+++ b/src/pubkey.h
@@ -139,7 +139,7 @@ public:
     template <typename Stream>
     void Unserialize(Stream& s)
     {
-        unsigned int len = ::ReadCompactSize(s);
+        const unsigned int len(::ReadCompactSize(s));
         if (len <= SIZE) {
             s.read((char*)vch, len);
             if (len != size()) {
@@ -147,9 +147,7 @@ public:
             }
         } else {
             // invalid pubkey, skip available data
-            char dummy;
-            while (len--)
-                s.read(&dummy, 1);
+            s.ignore(len);
             Invalidate();
         }
     }
diff --git a/src/span.h b/src/span.h
index de88fa08c5..3d96269768 100644
--- a/src/span.h
+++ b/src/span.h
@@ -180,6 +180,7 @@ public:
         return m_data[m_size - 1];
     }
     constexpr std::size_t size() const noexcept { return m_size; }
+    constexpr std::size_t size_bytes() const noexcept { return sizeof(C) * m_size; }
     constexpr bool empty() const noexcept { return size() == 0; }
     CONSTEXPR_IF_NOT_DEBUG C& operator[](std::size_t pos) const noexcept
     {
@@ -236,11 +237,35 @@ T& SpanPopBack(Span<T>& span)
     return back;
 }
 
+// From C++20 as_bytes and as_writeable_bytes
+template <typename T>
+Span<const std::byte> AsBytes(Span<T> s) noexcept
+{
+    return {reinterpret_cast<const std::byte*>(s.data()), s.size_bytes()};
+}
+template <typename T>
+Span<std::byte> AsWritableBytes(Span<T> s) noexcept
+{
+    return {reinterpret_cast<std::byte*>(s.data()), s.size_bytes()};
+}
+
+template <typename V>
+Span<const std::byte> MakeByteSpan(V&& v) noexcept
+{
+    return AsBytes(MakeSpan(std::forward<V>(v)));
+}
+template <typename V>
+Span<std::byte> MakeWritableByteSpan(V&& v) noexcept
+{
+    return AsWritableBytes(MakeSpan(std::forward<V>(v)));
+}
+
 // Helper functions to safely cast to unsigned char pointers.
 inline unsigned char* UCharCast(char* c) { return (unsigned char*)c; }
 inline unsigned char* UCharCast(unsigned char* c) { return c; }
 inline const unsigned char* UCharCast(const char* c) { return (unsigned char*)c; }
 inline const unsigned char* UCharCast(const unsigned char* c) { return c; }
+inline const unsigned char* UCharCast(const std::byte* c) { return reinterpret_cast<const unsigned char*>(c); }
 
 // Helper function to safely convert a Span to a Span<[const] unsigned char>.
 template <typename T> constexpr auto UCharSpanCast(Span<T> s) -> Span<typename std::remove_pointer<decltype(UCharCast(s.data()))>::type> { return {UCharCast(s.data()), s.size()}; }
diff --git a/src/streams.h b/src/streams.h
index 4df194db2d..7ddf405049 100644
--- a/src/streams.h
+++ b/src/streams.h
@@ -230,7 +230,7 @@ public:
         : nType{nTypeIn},
           nVersion{nVersionIn} {}
 
-    explicit CDataStream(Span<const uint8_t> sp, int nTypeIn, int nVersionIn)
+    explicit CDataStream(Span<const value_type> sp, int nTypeIn, int nVersionIn)
         : vch(sp.data(), sp.data() + sp.size()),
           nType{nTypeIn},
           nVersion{nVersionIn} {}
@@ -258,17 +258,17 @@ public:
     iterator end()                                   { return vch.end(); }
     size_type size() const                           { return vch.size() - nReadPos; }
     bool empty() const                               { return vch.size() == nReadPos; }
-    void resize(size_type n, value_type c=0)         { vch.resize(n + nReadPos, c); }
+    void resize(size_type n, value_type c = value_type{}) { vch.resize(n + nReadPos, c); }
     void reserve(size_type n)                        { vch.reserve(n + nReadPos); }
     const_reference operator[](size_type pos) const  { return vch[pos + nReadPos]; }
     reference operator[](size_type pos)              { return vch[pos + nReadPos]; }
     void clear()                                     { vch.clear(); nReadPos = 0; }
-    iterator insert(iterator it, const uint8_t x) { return vch.insert(it, x); }
-    void insert(iterator it, size_type n, const uint8_t x) { vch.insert(it, n, x); }
+    iterator insert(iterator it, const value_type x) { return vch.insert(it, x); }
+    void insert(iterator it, size_type n, const value_type x) { vch.insert(it, n, x); }
     value_type* data()                               { return vch.data() + nReadPos; }
     const value_type* data() const                   { return vch.data() + nReadPos; }
 
-    void insert(iterator it, std::vector<uint8_t>::const_iterator first, std::vector<uint8_t>::const_iterator last)
+    void insert(iterator it, std::vector<value_type>::const_iterator first, std::vector<value_type>::const_iterator last)
     {
         if (last == first) return;
         assert(last - first > 0);
@@ -282,7 +282,7 @@ public:
             vch.insert(it, first, last);
     }
 
-    void insert(iterator it, const char* first, const char* last)
+    void insert(iterator it, const value_type* first, const value_type* last)
     {
         if (last == first) return;
         assert(last - first > 0);
diff --git a/src/test/base64_tests.cpp b/src/test/base64_tests.cpp
index 714fccffaa..99f3ebdfa1 100644
--- a/src/test/base64_tests.cpp
+++ b/src/test/base64_tests.cpp
@@ -24,6 +24,16 @@ BOOST_AUTO_TEST_CASE(base64_testvectors)
         BOOST_CHECK_EQUAL(strDec, vstrIn[i]);
     }
 
+    {
+        const std::vector<uint8_t> in_u{0xff, 0x01, 0xff};
+        const std::vector<std::byte> in_b{std::byte{0xff}, std::byte{0x01}, std::byte{0xff}};
+        const std::string in_s{"\xff\x01\xff"};
+        const std::string out_exp{"/wH/"};
+        BOOST_CHECK_EQUAL(EncodeBase64(in_u), out_exp);
+        BOOST_CHECK_EQUAL(EncodeBase64(in_b), out_exp);
+        BOOST_CHECK_EQUAL(EncodeBase64(in_s), out_exp);
+    }
+
     // Decoding strings with embedded NUL characters should fail
     bool failure;
     (void)DecodeBase64("invalid\0"s, &failure);
diff --git a/src/test/streams_tests.cpp b/src/test/streams_tests.cpp
index ba2d879bb7..7aa4d9b3c3 100644
--- a/src/test/streams_tests.cpp
+++ b/src/test/streams_tests.cpp
@@ -172,7 +172,7 @@ BOOST_AUTO_TEST_CASE(streams_serializedata_xor)
     ds.Xor(key);
     BOOST_CHECK_EQUAL(
             std::string(expected_xor.begin(), expected_xor.end()),
-            std::string(ds.begin(), ds.end()));
+            ds.str());
 
     in.push_back('\x0f');
     in.push_back('\xf0');
@@ -189,7 +189,7 @@ BOOST_AUTO_TEST_CASE(streams_serializedata_xor)
     ds.Xor(key);
     BOOST_CHECK_EQUAL(
             std::string(expected_xor.begin(), expected_xor.end()),
-            std::string(ds.begin(), ds.end()));
+            ds.str());
 
     // Multi character key
 
@@ -210,7 +210,7 @@ BOOST_AUTO_TEST_CASE(streams_serializedata_xor)
     ds.Xor(key);
     BOOST_CHECK_EQUAL(
             std::string(expected_xor.begin(), expected_xor.end()),
-            std::string(ds.begin(), ds.end()));
+            ds.str());
 }
 
 BOOST_AUTO_TEST_CASE(streams_buffered_file)
diff --git a/src/test/util_tests.cpp b/src/test/util_tests.cpp
index 4095e2a739..c1fe68c870 100644
--- a/src/test/util_tests.cpp
+++ b/src/test/util_tests.cpp
@@ -186,12 +186,25 @@ BOOST_AUTO_TEST_CASE(util_HexStr)
         HexStr(Span<const unsigned char>(ParseHex_expected, ParseHex_expected)),
         "");
 
-    std::vector<unsigned char> ParseHex_vec(ParseHex_expected, ParseHex_expected + 5);
+    {
+        const std::vector<char> in_s{ParseHex_expected, ParseHex_expected + 5};
+        const Span<const uint8_t> in_u{MakeUCharSpan(in_s)};
+        const Span<const std::byte> in_b{MakeByteSpan(in_s)};
+        const std::string out_exp{"04678afdb0"};
 
-    BOOST_CHECK_EQUAL(
-        HexStr(ParseHex_vec),
-        "04678afdb0"
-    );
+        BOOST_CHECK_EQUAL(HexStr(in_u), out_exp);
+        BOOST_CHECK_EQUAL(HexStr(in_s), out_exp);
+        BOOST_CHECK_EQUAL(HexStr(in_b), out_exp);
+    }
+}
+
+BOOST_AUTO_TEST_CASE(span_write_bytes)
+{
+    std::array mut_arr{uint8_t{0xaa}, uint8_t{0xbb}};
+    const auto mut_bytes{MakeWritableByteSpan(mut_arr)};
+    mut_bytes[1] = std::byte{0x11};
+    BOOST_CHECK_EQUAL(mut_arr.at(0), 0xaa);
+    BOOST_CHECK_EQUAL(mut_arr.at(1), 0x11);
 }
 
 BOOST_AUTO_TEST_CASE(util_Join)
diff --git a/src/util/strencodings.cpp b/src/util/strencodings.cpp
index 84d806d65a..ed4624c3c5 100644
--- a/src/util/strencodings.cpp
+++ b/src/util/strencodings.cpp
@@ -138,11 +138,6 @@ std::string EncodeBase64(Span<const unsigned char> input)
     return str;
 }
 
-std::string EncodeBase64(const std::string& str)
-{
-    return EncodeBase64(MakeUCharSpan(str));
-}
-
 std::vector<unsigned char> DecodeBase64(const char* p, bool* pf_invalid)
 {
     static const int8_t decode64_table[256]{
diff --git a/src/util/strencodings.h b/src/util/strencodings.h
index 427f3e2651..ab5cf47adf 100644
--- a/src/util/strencodings.h
+++ b/src/util/strencodings.h
@@ -49,8 +49,8 @@ bool IsHexNumber(const std::string& str);
 std::vector<unsigned char> DecodeBase64(const char* p, bool* pf_invalid = nullptr);
 std::string DecodeBase64(const std::string& str, bool* pf_invalid = nullptr);
 std::string EncodeBase64(Span<const unsigned char> input);
-std::string EncodeBase64(const std::string& str);
-
+inline std::string EncodeBase64(Span<const std::byte> input) { return EncodeBase64(MakeUCharSpan(input)); }
+inline std::string EncodeBase64(const std::string& str) { return EncodeBase64(MakeUCharSpan(str)); }
 std::vector<unsigned char> DecodeBase32(const char* p, bool* pf_invalid = nullptr);
 std::string DecodeBase32(const std::string& str, bool* pf_invalid = nullptr);
 
@@ -194,6 +194,7 @@ std::optional<T> ToIntegral(const std::string& str)
  */
 std::string HexStr(const Span<const uint8_t> s);
 inline std::string HexStr(const Span<const char> s) { return HexStr(MakeUCharSpan(s)); }
+inline std::string HexStr(const Span<const std::byte> s) { return HexStr(MakeUCharSpan(s)); }
 
 /**
  * Format a paragraph of text to a fixed width, adding spaces for