diff --git a/src/netaddress.cpp b/src/netaddress.cpp
--- a/src/netaddress.cpp
+++ b/src/netaddress.cpp
@@ -342,10 +342,10 @@
 
 std::string CNetAddr::ToStringIP() const {
     if (IsTor()) {
-        return EncodeBase32(m_addr.data(), m_addr.size()) + ".onion";
+        return EncodeBase32(m_addr) + ".onion";
     }
     if (IsInternal()) {
-        return EncodeBase32(m_addr.data(), m_addr.size()) + ".internal";
+        return EncodeBase32(m_addr) + ".internal";
     }
     CService serv(*this, 0);
     struct sockaddr_storage sockaddr;
diff --git a/src/rpc/rawtransaction.cpp b/src/rpc/rawtransaction.cpp
--- a/src/rpc/rawtransaction.cpp
+++ b/src/rpc/rawtransaction.cpp
@@ -1550,7 +1550,7 @@
 
     CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
     ssTx << merged_psbt;
-    return EncodeBase64((uint8_t *)ssTx.data(), ssTx.size());
+    return EncodeBase64(MakeUCharSpan(ssTx));
 }
 
 static UniValue finalizepsbt(const Config &config,
@@ -1730,7 +1730,7 @@
     CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
     ssTx << psbtx;
 
-    return EncodeBase64((uint8_t *)ssTx.data(), ssTx.size());
+    return EncodeBase64(MakeUCharSpan(ssTx));
 }
 
 static UniValue converttopsbt(const Config &config,
@@ -1796,7 +1796,7 @@
     CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
     ssTx << psbtx;
 
-    return EncodeBase64((uint8_t *)ssTx.data(), ssTx.size());
+    return EncodeBase64(MakeUCharSpan(ssTx));
 }
 
 UniValue utxoupdatepsbt(const Config &config, const JSONRPCRequest &request) {
@@ -1898,7 +1898,7 @@
 
     CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
     ssTx << psbtx;
-    return EncodeBase64((uint8_t *)ssTx.data(), ssTx.size());
+    return EncodeBase64(MakeUCharSpan(ssTx));
 }
 
 UniValue joinpsbts(const Config &config, const JSONRPCRequest &request) {
@@ -2000,7 +2000,7 @@
 
     CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
     ssTx << shuffled_psbt;
-    return EncodeBase64((uint8_t *)ssTx.data(), ssTx.size());
+    return EncodeBase64(MakeUCharSpan(ssTx));
 }
 
 UniValue analyzepsbt(const Config &config, const JSONRPCRequest &request) {
diff --git a/src/util/message.cpp b/src/util/message.cpp
--- a/src/util/message.cpp
+++ b/src/util/message.cpp
@@ -61,7 +61,7 @@
         return false;
     }
 
-    signature = EncodeBase64(signature_bytes.data(), signature_bytes.size());
+    signature = EncodeBase64(signature_bytes);
 
     return true;
 }
diff --git a/src/util/strencodings.h b/src/util/strencodings.h
--- a/src/util/strencodings.h
+++ b/src/util/strencodings.h
@@ -55,11 +55,11 @@
 bool IsHexNumber(const std::string &str);
 std::vector<uint8_t> DecodeBase64(const char *p, bool *pf_invalid = nullptr);
 std::string DecodeBase64(const std::string &str, bool *pf_invalid = nullptr);
-std::string EncodeBase64(const uint8_t *pch, size_t len);
+std::string EncodeBase64(Span<const uint8_t> input);
 std::string EncodeBase64(const std::string &str);
 std::vector<uint8_t> DecodeBase32(const char *p, bool *pf_invalid = nullptr);
 std::string DecodeBase32(const std::string &str, bool *pf_invalid = nullptr);
-std::string EncodeBase32(const uint8_t *pch, size_t len);
+std::string EncodeBase32(Span<const uint8_t> input);
 std::string EncodeBase32(const std::string &str);
 
 void SplitHostPort(std::string in, int &portOut, std::string &hostOut);
diff --git a/src/util/strencodings.cpp b/src/util/strencodings.cpp
--- a/src/util/strencodings.cpp
+++ b/src/util/strencodings.cpp
@@ -134,13 +134,14 @@
     }
 }
 
-std::string EncodeBase64(const uint8_t *pch, size_t len) {
+std::string EncodeBase64(Span<const uint8_t> input) {
     static const char *pbase64 =
         "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
 
     std::string str;
-    str.reserve(((len + 2) / 3) * 4);
-    ConvertBits<8, 6, true>([&](int v) { str += pbase64[v]; }, pch, pch + len);
+    str.reserve(((input.size() + 2) / 3) * 4);
+    ConvertBits<8, 6, true>([&](int v) { str += pbase64[v]; }, input.begin(),
+                            input.end());
     while (str.size() % 4) {
         str += '=';
     }
@@ -148,7 +149,7 @@
 }
 
 std::string EncodeBase64(const std::string &str) {
-    return EncodeBase64((const uint8_t *)str.data(), str.size());
+    return EncodeBase64(MakeUCharSpan(str));
 }
 
 std::vector<uint8_t> DecodeBase64(const char *p, bool *pf_invalid) {
@@ -213,12 +214,13 @@
     return std::string((const char *)vchRet.data(), vchRet.size());
 }
 
-std::string EncodeBase32(const uint8_t *pch, size_t len) {
+std::string EncodeBase32(Span<const uint8_t> input) {
     static const char *pbase32 = "abcdefghijklmnopqrstuvwxyz234567";
 
     std::string str;
-    str.reserve(((len + 4) / 5) * 8);
-    ConvertBits<8, 5, true>([&](int v) { str += pbase32[v]; }, pch, pch + len);
+    str.reserve(((input.size() + 4) / 5) * 8);
+    ConvertBits<8, 5, true>([&](int v) { str += pbase32[v]; }, input.begin(),
+                            input.end());
     while (str.size() % 8) {
         str += '=';
     }
@@ -226,7 +228,7 @@
 }
 
 std::string EncodeBase32(const std::string &str) {
-    return EncodeBase32((const uint8_t *)str.data(), str.size());
+    return EncodeBase32(MakeUCharSpan(str));
 }
 
 std::vector<uint8_t> DecodeBase32(const char *p, bool *pf_invalid) {