重要提示：强制与可选的区别
电子账簿保存法包含「强制」部分和「可选」部分。这两者容易混淆，首先要理解其中的区别。
强制与可选的区分
强制（2024年1月起）
电子交易数据的电子保存
- Invoices/receipts received by email
- E-commerce order confirmations/receipts
- Cloud service statements
这些必须以电子数据形式保存
可选（自行选择）
纸质收据的扫描保存
- Paper receipts from stores
- Invoices received by mail
- Handwritten receipts
满足要求即可电子化（也可保留纸质原件）
扫描保存要求
如果要扫描纸质收据进行电子保存并销毁原件，需要满足以下要求：
1. Timestamp Attachment
A timestamp must be attached within approximately 7 business days of scanning. Alternatively, use a system that tracks modification/deletion history.
2. Resolution & Color Requirements
Resolution of 200dpi or higher, saved in color (RGB 256+ gradation each). Most smartphone cameras meet these requirements.
3. Size Information Preservation
For A4 or smaller documents, size information storage may not be required. For smartphone photos, the image should be viewable at original size or larger.
4. Search Functionality
Must be searchable by date, amount, and vendor. Range searches and combined conditions are also required.
5. Modification/Deletion History
When data is modified or deleted, the fact and content must be verifiable. Alternatively, use a system that prevents modifications/deletions.
注意：仅用手机拍照是不够的
仅仅用智能手机拍照无法满足上述要求（特别是时间戳·搜索功能）。需要使用符合电子账簿保存法的系统或应用。
电子交易数据保存（强制）
从2024年1月起，通过电子交易收到的数据必须以电子形式保存。不再允许打印成纸质保存。
适用的电子交易示例
- PDF invoices/receipts sent by email
- Order confirmations from Amazon, Rakuten, etc.
- Credit card online statements
- SaaS service statements (Slack, Notion, etc.)
- EDI system transaction data
保存要求
电子交易数据保存也需要确保「真实性」和「可视性」。简便方法是满足以下任一条件即可：
对应方法（任选一种）
- Receive data with timestamp already attached
- Attach timestamp promptly after receipt
- Use a system that prevents or logs modifications/deletions
- Establish and follow procedures for fraud prevention
Denpyo的对应方案
Denpyo符合电子账簿保存法的要求，只需用手机拍照即可以合规形式保存。
时间戳附加
拍摄时自动附加时间戳
搜索功能
可按日期·金额·交易对象搜索
防篡改
自动记录删除·修改历史
7年保存
云端安全长期保存
