diff --git a/apps/aether-gateway/src/handlers/admin/provider/delete_task.rs b/apps/aether-gateway/src/handlers/admin/provider/delete_task.rs
index f8969540e..83967be34 100644
--- a/apps/aether-gateway/src/handlers/admin/provider/delete_task.rs
+++ b/apps/aether-gateway/src/handlers/admin/provider/delete_task.rs
@@ -3,7 +3,10 @@ use crate::handlers::admin::provider::shared::support::{
     ADMIN_PROVIDER_MAPPING_PREVIEW_MAX_KEYS, ADMIN_PROVIDER_MAPPING_PREVIEW_MAX_MODELS,
 };
 use crate::handlers::admin::request::AdminAppState;
-use crate::handlers::admin::shared::{decrypt_catalog_secret_with_fallbacks, json_string_list};
+use crate::handlers::admin::shared::{
+    decrypt_catalog_secret_with_fallbacks, json_string_list, take_secret_prefix,
+    take_secret_suffix,
+};
 use crate::handlers::public::matches_model_mapping_for_models;
 use crate::{GatewayError, LocalProviderDeleteTaskState};
 use aether_data_contracts::repository::global_models::{
@@ -175,14 +178,15 @@ pub(crate) fn mapping_preview_masked_catalog_api_key(
 
     decrypt_catalog_secret_with_fallbacks(state.encryption_key(), ciphertext)
         .map(|value| {
-            if value.len() > 8 {
+            let char_count = value.chars().count();
+            if char_count > 8 {
                 format!(
                     "{}***{}",
-                    &value[..4],
-                    &value[value.len().saturating_sub(4)..]
+                    take_secret_prefix(&value, 4),
+                    take_secret_suffix(&value, 4)
                 )
-            } else if value.len() >= 2 {
-                format!("{}***", &value[..2])
+            } else if char_count >= 2 {
+                format!("{}***", take_secret_prefix(&value, 2))
             } else {
                 "***".to_string()
             }
diff --git a/apps/aether-gateway/src/handlers/admin/shared/mod.rs b/apps/aether-gateway/src/handlers/admin/shared/mod.rs
index c64bfdbe0..ad2b19ea0 100644
--- a/apps/aether-gateway/src/handlers/admin/shared/mod.rs
+++ b/apps/aether-gateway/src/handlers/admin/shared/mod.rs
@@ -12,6 +12,6 @@ pub(crate) use crate::handlers::shared::{
     masked_catalog_api_key, normalize_json_array, normalize_json_object, normalize_string_list,
     parse_catalog_auth_config_json, provider_catalog_key_supports_format,
     provider_key_health_summary, provider_key_status_snapshot_payload, query_param_bool,
-    query_param_optional_bool, query_param_value, unix_secs_to_rfc3339,
-    OFFICIAL_EXTERNAL_MODEL_PROVIDERS,
+    query_param_optional_bool, query_param_value, take_secret_prefix, take_secret_suffix,
+    unix_secs_to_rfc3339, OFFICIAL_EXTERNAL_MODEL_PROVIDERS,
 };
diff --git a/apps/aether-gateway/src/handlers/shared/catalog.rs b/apps/aether-gateway/src/handlers/shared/catalog.rs
index ff6cd741a..ca5b6cd5f 100644
--- a/apps/aether-gateway/src/handlers/shared/catalog.rs
+++ b/apps/aether-gateway/src/handlers/shared/catalog.rs
@@ -102,6 +102,29 @@ pub(crate) fn encrypt_catalog_secret_with_fallbacks(
     encrypt_python_fernet_plaintext(encryption_key.as_ref(), plaintext).ok()
 }
 
+pub(crate) fn take_secret_prefix(value: &str, prefix_chars: usize) -> &str {
+    let end = value
+        .char_indices()
+        .nth(prefix_chars)
+        .map(|(index, _)| index)
+        .unwrap_or(value.len());
+    &value[..end]
+}
+
+pub(crate) fn take_secret_suffix(value: &str, suffix_chars: usize) -> &str {
+    if suffix_chars == 0 {
+        return &value[value.len()..];
+    }
+
+    let start = value
+        .char_indices()
+        .rev()
+        .nth(suffix_chars - 1)
+        .map(|(index, _)| index)
+        .unwrap_or(0);
+    &value[start..]
+}
+
 pub(crate) fn masked_catalog_api_key(state: &AppState, key: &StoredProviderCatalogKey) -> String {
     match key.auth_type.trim() {
         "service_account" | "vertex_ai" => "[Service Account]".to_string(),
@@ -117,13 +140,13 @@ pub(crate) fn masked_catalog_api_key(state: &AppState, key: &StoredProviderCatal
             };
             decrypt_catalog_secret_with_fallbacks(state.encryption_key(), ciphertext)
                 .map(|value| {
-                    if value.len() <= 12 {
+                    if value.chars().count() <= 12 {
                         format!("{value}***")
                     } else {
                         format!(
                             "{}***{}",
-                            &value[..8],
-                            &value[value.len().saturating_sub(4)..]
+                            take_secret_prefix(&value, 8),
+                            take_secret_suffix(&value, 4)
                         )
                     }
                 })
@@ -1621,6 +1644,41 @@ mod tests {
         .expect("key transport should build")
     }
 
+    #[test]
+    fn masked_catalog_api_key_handles_unicode_plaintext_without_panicking() {
+        let state = AppState::new().expect("gateway should build");
+        let encrypted_api_key = encrypt_python_fernet_plaintext(
+            DEVELOPMENT_ENCRYPTION_KEY,
+            "测试-密钥-1234567890",
+        )
+        .expect("api key ciphertext should build");
+        let key = StoredProviderCatalogKey::new(
+            "key-unicode".to_string(),
+            "provider-test".to_string(),
+            "default".to_string(),
+            "api_key".to_string(),
+            None,
+            true,
+        )
+        .expect("key should build")
+        .with_transport_fields(
+            Some(json!(["openai:chat"])),
+            encrypted_api_key,
+            None,
+            None,
+            None,
+            None,
+            None,
+            None,
+            None,
+        )
+        .expect("key transport should build");
+
+        let masked = masked_catalog_api_key(&state, &key);
+        assert!(masked.contains("***"));
+        assert_ne!(masked, "***ERROR***");
+    }
+
     #[test]
     fn provider_key_status_snapshot_payload_backfills_missing_quota_from_upstream_metadata() {
         let mut key = sample_catalog_key();
diff --git a/apps/aether-gateway/src/handlers/shared/mod.rs b/apps/aether-gateway/src/handlers/shared/mod.rs
index 3bf090e4d..5c072ecc2 100644
--- a/apps/aether-gateway/src/handlers/shared/mod.rs
+++ b/apps/aether-gateway/src/handlers/shared/mod.rs
@@ -25,7 +25,7 @@ pub(crate) use self::catalog::{
     encrypt_catalog_secret_with_fallbacks, masked_catalog_api_key, parse_catalog_auth_config_json,
     provider_catalog_key_supports_format, provider_key_health_summary,
     provider_key_status_snapshot_payload, sync_provider_key_oauth_status_snapshot,
-    sync_provider_key_quota_status_snapshot,
+    sync_provider_key_quota_status_snapshot, take_secret_prefix, take_secret_suffix,
 };
 pub(crate) use self::email_templates::{
     admin_email_template_definition, admin_email_template_html_key,