diff --git a/src/rpc/rawtransaction.cpp b/src/rpc/rawtransaction.cpp
index abc8168c5..d6988ee3a 100644
--- a/src/rpc/rawtransaction.cpp
+++ b/src/rpc/rawtransaction.cpp
@@ -1300,7 +1300,7 @@ UniValue combinepsbt(const JSONRPCRequest& request)
 
     CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
     ssTx << merged_psbt;
-    return EncodeBase64((unsigned char*)ssTx.data(), ssTx.size());
+    return EncodeBase64(MakeUCharSpan(ssTx));
 }
 
 UniValue finalizepsbt(const JSONRPCRequest& request)
@@ -1435,7 +1435,7 @@ UniValue createpsbt(const JSONRPCRequest& request)
     CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
     ssTx << psbtx;
 
-    return EncodeBase64((unsigned char*)ssTx.data(), ssTx.size());
+    return EncodeBase64(MakeUCharSpan(ssTx));
 }
 
 UniValue converttopsbt(const JSONRPCRequest& request)
@@ -1502,7 +1502,7 @@ UniValue converttopsbt(const JSONRPCRequest& request)
     CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
     ssTx << psbtx;
 
-    return EncodeBase64((unsigned char*)ssTx.data(), ssTx.size());
+    return EncodeBase64(MakeUCharSpan(ssTx));
 }
 
 UniValue utxoupdatepsbt(const JSONRPCRequest& request)
@@ -1590,7 +1590,7 @@ UniValue utxoupdatepsbt(const JSONRPCRequest& request)
 
     CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
     ssTx << psbtx;
-    return EncodeBase64((unsigned char*)ssTx.data(), ssTx.size());
+    return EncodeBase64(MakeUCharSpan(ssTx));
 }
 
 UniValue joinpsbts(const JSONRPCRequest& request)
@@ -1683,7 +1683,7 @@ UniValue joinpsbts(const JSONRPCRequest& request)
 
     CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
     ssTx << shuffled_psbt;
-    return EncodeBase64((unsigned char*)ssTx.data(), ssTx.size());
+    return EncodeBase64(MakeUCharSpan(ssTx));
 }
 
 UniValue analyzepsbt(const JSONRPCRequest& request)
diff --git a/src/util/message.cpp b/src/util/message.cpp
index 1e7128d22..e1d5cff48 100644
--- a/src/util/message.cpp
+++ b/src/util/message.cpp
@@ -64,7 +64,7 @@ bool MessageSign(
         return false;
     }
 
-    signature = EncodeBase64(signature_bytes.data(), signature_bytes.size());
+    signature = EncodeBase64(signature_bytes);
 
     return true;
 }
diff --git a/src/util/strencodings.cpp b/src/util/strencodings.cpp
index ec29efc58..079a4529a 100644
--- a/src/util/strencodings.cpp
+++ b/src/util/strencodings.cpp
@@ -126,20 +126,20 @@ void SplitHostPort(std::string in, int &portOut, std::string &hostOut) {
         hostOut = in;
 }
 
-std::string EncodeBase64(const unsigned char* pch, size_t len)
+std::string EncodeBase64(Span<const unsigned char> 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 += '=';
     return str;
 }
 
 std::string EncodeBase64(const std::string& str)
 {
-    return EncodeBase64((const unsigned char*)str.data(), str.size());
+    return EncodeBase64(MakeUCharSpan(str));
 }
 
 std::vector<unsigned char> DecodeBase64(const char* p, bool* pf_invalid)
diff --git a/src/util/strencodings.h b/src/util/strencodings.h
index 1d0695a78..151921414 100644
--- a/src/util/strencodings.h
+++ b/src/util/strencodings.h
@@ -48,7 +48,7 @@ bool IsHex(const std::string& str);
 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(const unsigned char* pch, size_t len);
+std::string EncodeBase64(Span<const unsigned char> input);
 std::string EncodeBase64(const std::string& str);
 std::vector<unsigned char> DecodeBase32(const char* p, bool* pf_invalid = nullptr);
 std::string DecodeBase32(const std::string& str, bool* pf_invalid = nullptr);