├── Evidence.sol
└── README.md


/Evidence.sol:
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 1 | contract Evidence{
 2 |     uint CODE_SUCCESS = 0;
 3 |     uint FILE_NOT_EXIST = 3002;
 4 |     uint FILE_ALREADY_EXIST  = 3003;
 5 |     uint USER_NOT_EXIST = 3004;
 6 | 
 7 |     struct FileEvidence{
 8 |     bytes fileHash;
 9 |     uint fileUploadTime;
10 |     address owner;
11 |     }
12 |     struct User{
13 |         address addr;
14 |         uint count;
15 |         mapping(bytes => FileEvidence) filemap;
16 |     }
17 |     
18 |     // 文件hash对应的文件存证实体
19 |     mapping(bytes => FileEvidence) fileEvidenceMap;
20 | 
21 |     // 交易hash对应的文件存证实体
22 |     mapping(bytes => FileEvidence) tx2FileEvidenceMap;
23 | 
24 |     mapping(address => User) userMap;
25 | 
26 |     address[] userList;
27 |     function saveEvidence(bytes fileHash,uint fileUploadTime) returns(uint code){
28 |         //get filemap under sender
29 |         User storage user = userMap[msg.sender];
30 |         
31 |         if (user.addr == 0x0) {
32 |             user.addr = msg.sender;
33 |             userList.push(msg.sender);
34 |         } 
35 |         FileEvidence storage fileEvidence = user.filemap[fileHash];
36 |         if(fileEvidence.fileHash.length != 0){
37 |             return FILE_ALREADY_EXIST;
38 |         }
39 |         user.count += 1;
40 |         fileEvidence.fileHash = fileHash;
41 |         fileEvidence.fileUploadTime = fileUploadTime;
42 |         fileEvidence.owner = msg.sender;
43 |         user.filemap[fileHash] = fileEvidence;
44 |         return CODE_SUCCESS;
45 |     }
46 | 
47 |     function getEvidence(bytes fileHash) returns(uint code,bytes fHash,uint fUpLoadTime,address saverAddress) {
48 |         //get filemap under sender
49 |         User storage user = userMap[msg.sender];
50 |         if (user.addr == 0x0) {
51 |             return (USER_NOT_EXIST,"",0,msg.sender);
52 |         } 
53 |         FileEvidence memory fileEvidence = user.filemap[fileHash];
54 |         if(fileEvidence.fileHash.length == 0){
55 |             return (FILE_NOT_EXIST,"",0,msg.sender);
56 |         }
57 |         
58 |         return(CODE_SUCCESS,fileEvidence.fileHash,fileEvidence.fileUploadTime,msg.sender);
59 |     }
60 |     
61 |     function getUsers() returns(address[] users){
62 |         return userList;
63 |     }
64 | }
65 | 


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/README.md:
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 1 | # Evidence
 2 | 
 3 | 基于Solidity语言的，适用于存证场景的智能合约示例
 4 | 
 5 | # 场景描述
 6 | 
 7 | “存证”即“保全”，保全即证据固定与保管，是指用一定的形式将证据固定下来，加以妥善保管，以供司法人员或律师、认定案件事实时使用。
 8 | 文件hash一旦通过该合约存入区块链便不可删除和修改，可用于证明电子合同等法律文书的有效性。
 9 | 
10 | 方法清单：
11 | 
12 | - `function saveEvidence(bytes fileHash,uint fileUploadTime) returns(uint code)`:保存文件hash，文件hash会被保存到调用者的存证空间下；
13 | - `function getEvidence(bytes fileHash) returns(uint code,bytes fHash,uint fUpLoadTime,address saverAddress)`:从调用者的存证空间中搜索该hash，若搜索到便返回响应的存证详情，否则返回搜索失败的相应提示；
14 | - `function getUsers() returns(address[] users)`:查询用户列表，新的区块链账户若发起过saveEvidence请求，该账户便会被计入该列表。
15 | 


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