diff --git a/ofdgo_editor_attachment.go b/ofdgo_editor_attachment.go
index a73cd82..0273c96 100644
--- a/ofdgo_editor_attachment.go
+++ b/ofdgo_editor_attachment.go
@@ -52,7 +52,15 @@ func (e *Editor) AddAttachment(name string, data []byte) (string, error) {
 			return "", err
 		}
 	}
-	id := strconv.Itoa(maximum + 1)
+	attachments, err := base.reader.Attachments()
+	if err != nil {
+		return "", err
+	}
+	used := make(map[string]bool, len(attachments))
+	for _, attachment := range attachments {
+		used[attachment.ID] = true
+	}
+	id, maximum := nextAttachmentID(used, maximum)
 	file := e.packageName("Attachments/Attachment_" + id)
 	attrs := ofdAttrs{}
 	attrs.add("ID", id)
@@ -121,10 +129,24 @@ func (e *Editor) AddAttachment(name string, data []byte) (string, error) {
 	if err := e.commitAnnotationParts(base, parts); err != nil {
 		return "", err
 	}
-	e.maxID, e.source.idsReady = maximum+1, true
+	e.maxID, e.source.idsReady = maximum, true
 	return id, nil
 }
 
+// nextAttachmentID 分配以字母开头且不与已有附件重复的标识
+// 入参: used 已用附件标识, maximum 当前编号上限
+// 返回: string 附件标识, int 更新后的编号上限
+func nextAttachmentID(used map[string]bool, maximum int) (string, int) {
+	for {
+		maximum++
+		id := "a" + strconv.Itoa(maximum)
+		if !used[id] {
+			used[id] = true
+			return id, maximum
+		}
+	}
+}
+
 // RenameAttachment 修改附件显示名称，保留格式、内容及扩展字段，相同名称不产生撤销记录
 // 入参: id 附件标识, name 显示名称
 // 返回: error 名称或附件结构错误
diff --git a/ofdgo_editor_import.go b/ofdgo_editor_import.go
index 0a96273..37a591e 100644
--- a/ofdgo_editor_import.go
+++ b/ofdgo_editor_import.go
@@ -55,6 +55,7 @@ type editorPageImport struct {
 	templateParts map[string][]byte
 	defaultCS     string
 	attachments   map[string][]byte
+	attachmentIDs map[string]bool
 	copyPage      bool
 	strictLinks   bool
 	progress      editorProgress
@@ -957,10 +958,14 @@ func (m *editorPageImport) encode(entry editorImportEntry, node *editorXML) ([]b
 		var err error
 		switch key {
 		case "ID":
-			if name == "Signature" || name == "StampAnnot" {
+			if name == "Attachment" {
+				value, err = m.attachmentID(value)
+			} else if name == "Signature" || name == "StampAnnot" {
 				value = name + ":" + value
+				value = m.id(value)
+			} else {
+				value = m.id(value)
 			}
-			value = m.id(value)
 		case "PageID":
 			if !m.copyPage || m.pages[editorImportKey(value)] {
 				value, err = m.reference(value)
@@ -1173,25 +1178,11 @@ func (m *editorPageImport) annotations() ([]byte, error) {
 // 入参: id 来源附件标识
 // 返回: string 新标识, error 错误信息
 func (m *editorPageImport) attachment(id string) (string, error) {
-	key := editorImportKey(id)
 	if m.copyPage {
-		if mapped := m.ids[key]; mapped != "" {
-			return mapped, nil
-		}
-		attachments, err := m.reader.Attachments()
-		if err != nil {
-			return "", err
-		}
-		for _, attachment := range attachments {
-			if editorImportKey(attachment.ID) == key {
-				m.ids[key] = attachment.ID
-				return attachment.ID, nil
-			}
-		}
 		return id, nil
 	}
-	if _, exists := m.attachments[key]; exists {
-		return m.id(id), nil
+	if _, exists := m.attachments[id]; exists {
+		return m.attachmentID(id)
 	}
 	name := m.reader.ResPath(m.reader.OFD.DocBody[m.reader.documentIndex].DocRoot)
 	if m.doc.Attachments.Path != "" {
@@ -1210,15 +1201,41 @@ func (m *editorPageImport) attachment(id string) (string, error) {
 	}
 	if root != nil {
 		for _, node := range root.children {
-			if node.name.Local == "Attachment" && editorImportKey(node.attr("ID")) == key {
-				m.attachments[key], err = m.encode(editorImportEntry{name: name, data: data}, node)
-				return m.id(id), err
+			if node.name.Local == "Attachment" && node.attr("ID") == id {
+				m.attachments[id], err = m.encode(editorImportEntry{name: name, data: data}, node)
+				if err != nil {
+					return "", err
+				}
+				return m.attachmentID(id)
 			}
 		}
 	}
 	return "", fmt.Errorf("attachment %q not found", id)
 }
 
+// attachmentID 为来源附件分配独立的文本标识，避免与数值型资源标识混淆
+// 入参: id 来源附件标识
+// 返回: string 目标附件标识, error 附件索引错误
+func (m *editorPageImport) attachmentID(id string) (string, error) {
+	key := "Attachment:" + id
+	if mapped := m.ids[key]; mapped != "" {
+		return mapped, nil
+	}
+	if m.attachmentIDs == nil {
+		attachments, err := m.target.Attachments()
+		if err != nil {
+			return "", err
+		}
+		m.attachmentIDs = make(map[string]bool, len(attachments))
+		for _, attachment := range attachments {
+			m.attachmentIDs[attachment.ID] = true
+		}
+	}
+	mapped, maximum := nextAttachmentID(m.attachmentIDs, m.maximum)
+	m.maximum, m.ids[key] = maximum, mapped
+	return mapped, nil
+}
+
 // signatures 复制所选页面的签章及原始验证凭据，过滤其他页面的签章位置
 // 返回: []byte 签名索引条目, error 错误信息
 func (m *editorPageImport) signatures() ([]byte, error) {
diff --git a/ofdgo_sign.go b/ofdgo_sign.go
index 77ce315..a61565d 100644
--- a/ofdgo_sign.go
+++ b/ofdgo_sign.go
@@ -126,7 +126,7 @@ func (r *Reader) SignatureStampPositions(stamps []SignatureStamp) ([]SignatureSt
 	pages := signaturePageNumbers(doc)
 	positions := make([]SignatureStampPosition, 0, len(stamps))
 	for _, stamp := range stamps {
-		page, ok := pages[stamp.PageRef]
+		page, ok := resourceValue(pages, stamp.PageRef)
 		if !ok {
 			return nil, fmt.Errorf("signature stamp page not found: %s", stamp.PageRef)
 		}
@@ -183,6 +183,7 @@ func (r *Reader) parseSignatures(doc *Document) error {
 	if err := xml.NewDecoder(f).Decode(&signatures); err != nil {
 		return err
 	}
+	pages := signaturePageNumbers(doc)
 	for _, sigRef := range signatures.List {
 		func(sigRef Signature) {
 			sigPath := resolveResourcePath(sigListPath, "", sigRef.BaseLoc)
@@ -217,7 +218,11 @@ func (r *Reader) parseSignatures(doc *Document) error {
 				return
 			}
 			for _, annot := range sigFile.SignedInfo.StampAnnot {
-				pageID := annot.PageRef
+				page, ok := resourceValue(pages, annot.PageRef)
+				if !ok {
+					continue
+				}
+				pageID := doc.Pages.Page[page-1].ID
 				bbox, err := parseSignatureStampBox(annot.Boundary)
 				if err != nil {
 					continue
diff --git a/ofdgo_sign_write_stamp.go b/ofdgo_sign_write_stamp.go
index bc99579..e551f6f 100644
--- a/ofdgo_sign_write_stamp.go
+++ b/ofdgo_sign_write_stamp.go
@@ -98,10 +98,11 @@ func signatureWriteStamps(r *Reader, stamps []SignatureStamp, seal bool) ([]Sign
 	if len(result) != 0 {
 		pages := make(map[string]bool)
 		for _, page := range doc.Pages.Page {
-			if page.ID == "" || pages[page.ID] {
+			id := editorResourceID(page.ID)
+			if id == "" || pages[id] {
 				return nil, fmt.Errorf("ambiguous stamp page ID: %s", page.ID)
 			}
-			pages[page.ID] = true
+			pages[id] = true
 		}
 	}
 	ids := make(map[string]bool)