[帮助][115生活]什么是SHA1？
一、核心价值定位
在网盘中，SHA1的本质角色是「数据身份证」生成器，
通过数学变换将海量用户文件映射为全球唯一的紧凑标识符，解决以下两类核心痛点：
①存储效率优化（去重 & 压缩冗余）
②传输可靠性保障（断点续传 & 文件校验）
二、关键技术作用解析
1. 极速秒传原理（节省时间和宽带成本）
当你上传一个 10GB 的视频文件时：
后台流程：
先计算文件的sha1值 → A8F9B2...（40位十六进制字符串）
向服务器查询是否存在相同哈希值的文件记录，
若存在：直接关联现有存储副本，跳过实际上传（仅需元数据写入），实现所谓的"秒传"。
若不存在：才开始真正上传文件内容
2.智能存储去重（降低存储成本）
当100个用户上传同一个10G文件时：
传统存储 | SHA1优化存储 |
每个用户上传时独立存储， 实际存储100X10=1000G物理空间 | 相同内容文件共享唯一存储副本， 实际存储10G物理空间 + 100条元数据记录。 |
3.断点续传保障(提升传输鲁棒性)
当网络中断导致上传/下载失败时恢复机制：
①根据已上传/下载部分数据的 SHA-1 片段值
②定位到服务器端对应的存储位置
③仅续传缺失部分数据块
对比方案优势：
方案 | 传输进度 | 带宽消耗 |
传统传输 | 从头开始 | 全额带宽 |
基于SHA1分块校验 | 从断点继续 | 仅补传缺失块 |
4.验证文件传输完整性
①上传：
上传前计算SHA1值的过程相当于预校验，确保本地文件未损坏后再上传。
若上传后服务器返回的SHA1值与本地不一致，提示用户重新上传或检查文件状态，确保用户上传数据的完整。
②下载：
下载完成后，用户可通过对比本地文件计算出的SHA1值与网盘提供的官方SHA1值，确认文件是否完整且未被篡改，若两者不一致，表明文件可能在传输过程中损坏，便于用户即时发现和获取文件下载的完整性。
用户可使用115浏览器，在菜单-设置-上传下载-开启“文件完整性校验”功能实现。
下方为英文版教程
[Help][115 Life] What is SHA1?
I. Core Value Positioning
In cloud storage services, SHA1 fundamentally acts as a unique digital identifier generator. Through mathematical transformations, it maps massive user files into globally unique, compact identifiers, addressing two critical pain points:
① Storage Efficiency Optimization (Duplicate Removal & Redundancy Reduction)
② Transmission Reliability Assurance (Resume Capability & File Verification)
Key Technical Function Analysis
1. Instantaneous Upload Mechanism (Saves Time & Bandwidth Costs)
When uploading a 10GB video file:
Backend Process:
Calculate the file’s SHA1 value → A8F9B2... (40-character hexadecimal string)
Query the server for existing records with identical hash values.
✅If found: Directly link to the existing stored copy, skipping actual upload (only metadata written) – achieving "secondary transmission."
❌If not found: Initiate full file upload.
2. Intelligent Storage Deduplication (Reduces Storage Costs)
When 100 users upload the same 10GB file:
Approach | Traditional Storage | SHA1-Optimized Storage |
Per-user Handling | Independent storage per user | Single shared copy |
Physical Space | 100 × 10GB = 1,000GB | 10GB + 100 metadata entries |
3. Resume Interrupted Transfers (Enhances Transmission Robustness)
Network interruption recovery mechanism:
① Use SHA-1 fragment values of partially uploaded/downloaded data.
② Locate corresponding server-side storage positions.
③ Resume transmitting only missing data blocks.
Advantages Over Traditional Methods:
Method | Progress Status | Bandwidth Consumption |
Conventional | Start from beginning | Full bandwidth usage |
SHA-1 Block Verification | Continue from breakpoint | Only missing blocks resent |
4. File Transmission Integrity Verification
① Upload Phase:
Pre-upload SHA1 calculation serves as preliminary validation, ensuring local files are undamaged before upload. If post-upload server SHA1 mismatches local values, users are prompted to reupload or check
file status, guaranteeing data completeness.
② Download Phase:After download completion, users can compare locally computed SHA1 values against official ones provided by the cloud service. Discrepancies indicate potential transmission corruption,
ensuring downloaded files remain intact.
Implementation Tip: Enable "File Integrity Verification" in 115 Browser