diff --git a/context.go b/context.go
index 5174033eb3..8757a32ad8 100644
--- a/context.go
+++ b/context.go
@@ -132,9 +132,10 @@ func (c *Context) Copy() *Context {
 	cp.handlers = nil
 	cp.fullPath = c.fullPath
 
-	cKeys := c.Keys
 	c.mu.RLock()
-	cp.Keys = maps.Clone(cKeys)
+	if c.Keys != nil {
+		cp.Keys = maps.Clone(c.Keys)
+	}
 	c.mu.RUnlock()
 
 	cParams := c.Params
diff --git a/recovery.go b/recovery.go
index bbf1d565bf..128654ace4 100644
--- a/recovery.go
+++ b/recovery.go
@@ -91,16 +91,25 @@ func CustomRecoveryWithWriter(out io.Writer, handle RecoveryFunc) HandlerFunc {
 	}
 }
 
-// secureRequestDump returns a sanitized HTTP request dump where the Authorization header,
-// if present, is replaced with a masked value ("Authorization: *") to avoid leaking sensitive credentials.
+// secureRequestDump returns a sanitized HTTP request dump where the Authorization
+// and Proxy-Authorization headers, if present, are replaced with a masked value
+// (e.g. "Authorization: *") to avoid leaking sensitive credentials.
 //
-// Currently, only the Authorization header is sanitized. All other headers and request data remain unchanged.
+// Header name matching is case-insensitive since HTTP headers are case-insensitive
+// per RFC 9110. All other headers and request data remain unchanged.
 func secureRequestDump(r *http.Request) string {
 	httpRequest, _ := httputil.DumpRequest(r, false)
 	lines := strings.Split(bytesconv.BytesToString(httpRequest), "\r\n")
+	const (
+		authPrefix  = "Authorization:"
+		proxyPrefix = "Proxy-Authorization:"
+	)
 	for i, line := range lines {
-		if strings.HasPrefix(line, "Authorization:") {
+		switch {
+		case len(line) >= len(authPrefix) && strings.EqualFold(line[:len(authPrefix)], authPrefix):
 			lines[i] = "Authorization: *"
+		case len(line) >= len(proxyPrefix) && strings.EqualFold(line[:len(proxyPrefix)], proxyPrefix):
+			lines[i] = "Proxy-Authorization: *"
 		}
 	}
 	return strings.Join(lines, "\r\n")
diff --git a/recovery_test.go b/recovery_test.go
index 028c4ad6d6..151f2ccc8f 100644
--- a/recovery_test.go
+++ b/recovery_test.go
@@ -274,25 +274,67 @@ func TestSecureRequestDump(t *testing.T) {
 			wantNotContain: "Bearer secret-token",
 		},
 		{
+			// Bypass http.Header.Set canonicalization to put a lowercase
+			// header name on the wire and verify case-insensitive matching.
 			name: "authorization header lowercase",
 			req: func() *http.Request {
 				r, _ := http.NewRequest(http.MethodGet, "http://example.com", nil)
-				r.Header.Set("authorization", "some-secret")
+				r.Header["authorization"] = []string{"some-secret"}
 				return r
 			}(),
 			wantContains:   "Authorization: *",
 			wantNotContain: "some-secret",
 		},
+		{
+			name: "AUTHORIZATION header uppercase",
+			req: func() *http.Request {
+				r, _ := http.NewRequest(http.MethodGet, "http://example.com", nil)
+				r.Header["AUTHORIZATION"] = []string{"UPPER-SECRET"}
+				return r
+			}(),
+			wantContains:   "Authorization: *",
+			wantNotContain: "UPPER-SECRET",
+		},
 		{
 			name: "Authorization header mixed case",
 			req: func() *http.Request {
 				r, _ := http.NewRequest(http.MethodGet, "http://example.com", nil)
-				r.Header.Set("AuThOrIzAtIoN", "token123")
+				r.Header["AuThOrIzAtIoN"] = []string{"token123"}
 				return r
 			}(),
 			wantContains:   "Authorization: *",
 			wantNotContain: "token123",
 		},
+		{
+			name: "Proxy-Authorization header",
+			req: func() *http.Request {
+				r, _ := http.NewRequest(http.MethodGet, "http://example.com", nil)
+				r.Header.Set("Proxy-Authorization", "Basic cHJveHk6c2VjcmV0")
+				return r
+			}(),
+			wantContains:   "Proxy-Authorization: *",
+			wantNotContain: "Basic cHJveHk6c2VjcmV0",
+		},
+		{
+			name: "proxy-authorization header lowercase",
+			req: func() *http.Request {
+				r, _ := http.NewRequest(http.MethodGet, "http://example.com", nil)
+				r.Header["proxy-authorization"] = []string{"Basic bG93ZXI="}
+				return r
+			}(),
+			wantContains:   "Proxy-Authorization: *",
+			wantNotContain: "Basic bG93ZXI=",
+		},
+		{
+			name: "PROXY-AUTHORIZATION header uppercase",
+			req: func() *http.Request {
+				r, _ := http.NewRequest(http.MethodGet, "http://example.com", nil)
+				r.Header["PROXY-AUTHORIZATION"] = []string{"Basic VVBQRVI="}
+				return r
+			}(),
+			wantContains:   "Proxy-Authorization: *",
+			wantNotContain: "Basic VVBQRVI=",
+		},
 		{
 			name: "No Authorization header",
 			req: func() *http.Request {
diff --git a/render/json.go b/render/json.go
index 2f98676cff..f2ccaf8c64 100644
--- a/render/json.go
+++ b/render/json.go
@@ -160,11 +160,19 @@ func (r AsciiJSON) Render(w http.ResponseWriter) error {
 	}
 
 	var buffer bytes.Buffer
-	escapeBuf := make([]byte, 0, 6) // Preallocate 6 bytes for Unicode escape sequences
+	escapeBuf := make([]byte, 0, 12) // Preallocate for surrogate pair escape sequences
 
 	for _, r := range bytesconv.BytesToString(ret) {
 		if r > unicode.MaxASCII {
-			escapeBuf = fmt.Appendf(escapeBuf[:0], "\\u%04x", r) // Reuse escapeBuf
+			if r > 0xFFFF {
+				// Supplementary plane: encode as UTF-16 surrogate pair per RFC 8259
+				r -= 0x10000
+				high := 0xD800 + (r>>10)&0x3FF
+				low := 0xDC00 + r&0x3FF
+				escapeBuf = fmt.Appendf(escapeBuf[:0], "\\u%04x\\u%04x", high, low)
+			} else {
+				escapeBuf = fmt.Appendf(escapeBuf[:0], "\\u%04x", r)
+			}
 			buffer.Write(escapeBuf)
 		} else {
 			buffer.WriteByte(byte(r))
diff --git a/render/render_test.go b/render/render_test.go
index f63878b966..c234d18958 100644
--- a/render/render_test.go
+++ b/render/render_test.go
@@ -261,6 +261,17 @@ func TestRenderAsciiJSON(t *testing.T) {
 	assert.Equal(t, "3.1415926", w2.Body.String())
 }
 
+func TestRenderAsciiJSONSupplementaryUnicode(t *testing.T) {
+	w := httptest.NewRecorder()
+	data := map[string]string{"emoji": "😀"}
+
+	err := (AsciiJSON{data}).Render(w)
+	require.NoError(t, err)
+	// U+1F600 must be encoded as UTF-16 surrogate pair per RFC 8259.
+	// Use Contains to verify the surrogate pair encoding in the raw output.
+	assert.Contains(t, w.Body.String(), `\ud83d\ude00`)
+}
+
 func TestRenderAsciiJSONFail(t *testing.T) {
 	w := httptest.NewRecorder()
 	data := make(chan int)