本文為英文版的機器翻譯版本，如內容有任何歧義或不一致之處，概以英文版為準。 # 教學課程：使用 AWS SDK 驗證資料 **重要** 終止支援通知：現有客戶將可以使用 Amazon QLDB，直到 07/31/2025 終止支援為止。如需詳細資訊，請參閱[將 Amazon QLDB Ledger 遷移至 Amazon Aurora PostgreSQL](https://aws.amazon.com/blogs/database/migrate-an-amazon-qldb-ledger-to-amazon-aurora-postgresql/)。在本教學課程中，您會透過 AWS SDK 使用 QLDB API 來驗證 Amazon QLDB 總帳中的文件修訂雜湊和日誌區塊雜湊。您也可以使用 QLDB 驅動程式來查詢文件修訂版。請考慮範例，其中您有一個文件修訂版本，其中包含車輛識別號碼 (VIN) 為之車輛的資料`KM8SRDHF6EU074761`。文件修訂位於名為的分類帳中的`VehicleRegistration`資料表中`vehicle-registration`。假設您想要驗證此車輛的文件修訂和包含修訂的日誌區塊的完整性。 **注意** 如需討論實際使用案例情況下密碼編譯驗證價值的詳細 AWS 部落格文章，請參閱[使用 Amazon QLDB 進行真實世界密碼編譯驗證](https://aws.amazon.com/blogs/database/real-world-cryptographic-verification-with-amazon-qldb/)。 **Topics** + [ ## 先決條件 ](#verification.tutorial.prereqs) + [ ## 步驟 1：請求摘要 ](#verification.tutorial.step-1) + [ ## 步驟 2：查詢文件修訂 ](#verification.tutorial.step-2) + [ ## 步驟 3：請求修訂的證明 ](#verification.tutorial.step-3) + [ ## 步驟 4：從修訂重新計算摘要 ](#verification.tutorial.step-4) + [ ## 步驟 5：請求日誌區塊的證明 ](#verification.tutorial.step-5) + [ ## 步驟 6：從區塊重新計算摘要 ](#verification.tutorial.step-6) + [ ## 執行完整程式碼範例 ](#verification.tutorial.full) ## 先決條件開始之前，請務必執行下列動作： 1. 完成下各自的先決條件，為您選擇的語言設定 QLDB 驅動程式[Amazon QLDB 驅動程式入門](getting-started-driver.md)。這包括註冊 AWS、授予開發的程式設計存取權，以及設定您的開發環境。 1. 依照中的步驟 1-2 [Amazon QLDB 主控台入門](getting-started.md) 建立名為的總帳，`vehicle-registration`並使用預先定義的範例資料載入它。接著，檢閱下列步驟以了解驗證的運作方式，然後從頭到尾執行完整的程式碼範例。 ## 步驟 1：請求摘要您必須先向總帳請求摘要`vehicle-registration`以供日後使用，才能驗證資料。 ------ #### [ Java ] ``` // Get a digest GetDigestRequest digestRequest = new GetDigestRequest().withName(ledgerName); GetDigestResult digestResult = client.getDigest(digestRequest); java.nio.ByteBuffer digest = digestResult.getDigest(); // expectedDigest is the buffer we will use later to compare against our calculated digest byte[] expectedDigest = new byte[digest.remaining()]; digest.get(expectedDigest); ``` ------ #### [ .NET ] ``` // Get a digest GetDigestRequest getDigestRequest = new GetDigestRequest { Name = ledgerName }; GetDigestResponse getDigestResponse = client.GetDigestAsync(getDigestRequest).Result; // expectedDigest is the buffer we will use later to compare against our calculated digest MemoryStream digest = getDigestResponse.Digest; byte[] expectedDigest = digest.ToArray(); ``` ------ #### [ Go ] ``` // Get a digest currentLedgerName := ledgerName input := qldb.GetDigestInput{Name: ¤tLedgerName} digestOutput, err := client.GetDigest(&input) if err != nil { panic(err) } // expectedDigest is the buffer we will later use to compare against our calculated digest expectedDigest := digestOutput.Digest ``` ------ #### [ Node.js ] ``` // Get a digest const getDigestRequest: GetDigestRequest = { Name: ledgerName }; const getDigestResponse: GetDigestResponse = await qldbClient.getDigest(getDigestRequest).promise(); // expectedDigest is the buffer we will later use to compare against our calculated digest const expectedDigest: Uint8Array = getDigestResponse.Digest; ``` ------ #### [ Python ] ``` # Get a digest get_digest_response = qldb_client.get_digest(Name=ledger_name) # expected_digest is the buffer we will later use to compare against our calculated digest expected_digest = get_digest_response.get('Digest') digest_tip_address = get_digest_response.get('DigestTipAddress') ``` ------ ## 步驟 2：查詢文件修訂使用 QLDB 驅動程式查詢與 VIN 相關聯的區塊地址、雜湊和文件 IDs`KM8SRDHF6EU074761`。 ------ #### [ Java ] ``` // Retrieve info for the given vin's document revisions Result result = driver.execute(txn -> { final String query = String.format("SELECT blockAddress, hash, metadata.id FROM _ql_committed_%s WHERE data.VIN = '%s'", tableName, vin); return txn.execute(query); }); ``` ------ #### [ .NET ] ``` // Retrieve info for the given vin's document revisions var result = driver.Execute(txn => { string query = $"SELECT blockAddress, hash, metadata.id FROM _ql_committed_{tableName} WHERE data.VIN = '{vin}'"; return txn.Execute(query); }); ``` ------ #### [ Go ] ``` // Retrieve info for the given vin's document revisions result, err := driver.Execute(context.Background(), func(txn qldbdriver.Transaction) (interface{}, error) { statement := fmt.Sprintf( "SELECT blockAddress, hash, metadata.id FROM _ql_committed_%s WHERE data.VIN = '%s'", tableName, vin) result, err := txn.Execute(statement) if err != nil { return nil, err } results := make([]map[string]interface{}, 0) // Convert the result set into a map for result.Next(txn) { var doc map[string]interface{} err := ion.Unmarshal(result.GetCurrentData(), &doc) if err != nil { return nil, err } results = append(results, doc) } return results, nil }) if err != nil { panic(err) } resultSlice := result.([]map[string]interface{}) ``` ------ #### [ Node.js ] ``` const result: dom.Value[] = await driver.executeLambda(async (txn: TransactionExecutor): Promise => { const query: string = `SELECT blockAddress, hash, metadata.id FROM _ql_committed_${tableName} WHERE data.VIN = '${vin}'`; const queryResult: Result = await txn.execute(query); return queryResult.getResultList(); }); ``` ------ #### [ Python ] ``` def query_doc_revision(txn): query = "SELECT blockAddress, hash, metadata.id FROM _ql_committed_{} WHERE data.VIN = '{}'".format(table_name, vin) return txn.execute_statement(query) # Retrieve info for the given vin's document revisions result = qldb_driver.execute_lambda(query_doc_revision) ``` ------ ## 步驟 3：請求修訂的證明逐一查看查詢結果，並使用每個區塊地址和文件 ID 以及分類帳名稱來提交`GetRevision`請求。*若要取得修訂的證明，您還必須提供先前儲存摘要的提示地址。*此 API 操作會傳回包含文件修訂和修訂證明的物件。如需修訂結構及其內容的詳細資訊，請參閱 [查詢文件中繼資料](working.metadata.md)。 ------ #### [ Java ] ``` for (IonValue ionValue : result) { IonStruct ionStruct = (IonStruct)ionValue; // Get the requested fields IonValue blockAddress = ionStruct.get("blockAddress"); IonBlob hash = (IonBlob)ionStruct.get("hash"); String metadataId = ((IonString)ionStruct.get("id")).stringValue(); System.out.printf("Verifying document revision for id '%s'%n", metadataId); String blockAddressText = blockAddress.toString(); // Submit a request for the revision GetRevisionRequest revisionRequest = new GetRevisionRequest() .withName(ledgerName) .withBlockAddress(new ValueHolder().withIonText(blockAddressText)) .withDocumentId(metadataId) .withDigestTipAddress(digestResult.getDigestTipAddress()); // Get a result back GetRevisionResult revisionResult = client.getRevision(revisionRequest); ... } ``` ------ #### [ .NET ] ``` foreach (IIonValue ionValue in result) { IIonStruct ionStruct = ionValue; // Get the requested fields IIonValue blockAddress = ionStruct.GetField("blockAddress"); IIonBlob hash = ionStruct.GetField("hash"); String metadataId = ionStruct.GetField("id").StringValue; Console.WriteLine($"Verifying document revision for id '{metadataId}'"); // Use an Ion Reader to convert block address to text IIonReader reader = IonReaderBuilder.Build(blockAddress); StringWriter sw = new StringWriter(); IIonWriter textWriter = IonTextWriterBuilder.Build(sw); textWriter.WriteValues(reader); string blockAddressText = sw.ToString(); // Submit a request for the revision GetRevisionRequest revisionRequest = new GetRevisionRequest { Name = ledgerName, BlockAddress = new ValueHolder { IonText = blockAddressText }, DocumentId = metadataId, DigestTipAddress = getDigestResponse.DigestTipAddress }; // Get a response back GetRevisionResponse revisionResponse = client.GetRevisionAsync(revisionRequest).Result; ... } ``` ------ #### [ Go ] ``` for _, value := range resultSlice { // Get the requested fields ionBlockAddress, err := ion.MarshalText(value["blockAddress"]) if err != nil { panic(err) } blockAddress := string(ionBlockAddress) metadataId := value["id"].(string) documentHash := value["hash"].([]byte) fmt.Printf("Verifying document revision for id '%s'\n", metadataId) // Submit a request for the revision revisionInput := qldb.GetRevisionInput{ BlockAddress: &qldb.ValueHolder{IonText: &blockAddress}, DigestTipAddress: digestOutput.DigestTipAddress, DocumentId: &metadataId, Name: ¤tLedgerName, } // Get a result back revisionOutput, err := client.GetRevision(&revisionInput) if err != nil { panic(err) } ... } ``` ------ #### [ Node.js ] ``` for (let value of result) { // Get the requested fields const blockAddress: dom.Value = value.get("blockAddress"); const hash: dom.Value = value.get("hash"); const metadataId: string = value.get("id").stringValue(); console.log(`Verifying document revision for id '${metadataId}'`); // Submit a request for the revision const revisionRequest: GetRevisionRequest = { Name: ledgerName, BlockAddress: { IonText: dumpText(blockAddress) }, DocumentId: metadataId, DigestTipAddress: getDigestResponse.DigestTipAddress }; // Get a response back const revisionResponse: GetRevisionResponse = await qldbClient.getRevision(revisionRequest).promise(); ... } ``` ------ #### [ Python ] ``` for value in result: # Get the requested fields block_address = value['blockAddress'] document_hash = value['hash'] metadata_id = value['id'] print("Verifying document revision for id '{}'".format(metadata_id)) # Submit a request for the revision and get a result back proof_response = qldb_client.get_revision(Name=ledger_name, BlockAddress=block_address_to_dictionary(block_address), DocumentId=metadata_id, DigestTipAddress=digest_tip_address) ``` ------ 然後，擷取所請求修訂的證明。 QLDB API 會將證據傳回為節點雜湊的排序清單的字串表示法。若要將此字串轉換為節點雜湊的二進位表示式清單，您可以使用 Amazon Ion 程式庫中的 Ion 讀取器。如需使用 Ion 程式庫的詳細資訊，請參閱 [Amazon Ion 技術指南](http://amzn.github.io/ion-docs/guides/cookbook.html#reading-and-writing-ion-data)。 ------ #### [ Java ] 在此範例中，您使用 `IonReader`執行二進位轉換。 ``` String proofText = revisionResult.getProof().getIonText(); // Take the proof and convert it to a list of byte arrays List internalHashes = new ArrayList<>(); IonReader reader = SYSTEM.newReader(proofText); reader.next(); reader.stepIn(); while (reader.next() != null) { internalHashes.add(reader.newBytes()); } ``` ------ #### [ .NET ] 在此範例中，您使用將驗證`IonLoader`載入 Ion 資料包。 ``` string proofText = revisionResponse.Proof.IonText; IIonDatagram proofValue = IonLoader.Default.Load(proofText); ``` ------ #### [ Go ] 在此範例中，您使用 Ion 讀取器將驗證轉換為二進位，並逐一查看驗證的節點雜湊清單。 ``` proofText := revisionOutput.Proof.IonText // Use ion.Reader to iterate over the proof's node hashes reader := ion.NewReaderString(*proofText) // Enter the struct containing node hashes reader.Next() if err := reader.StepIn(); err != nil { panic(err) } ``` ------ #### [ Node.js ] 在此範例中，您會使用 `load`函數來執行二進位轉換。 ``` let proofValue: dom.Value = load(revisionResponse.Proof.IonText); ``` ------ #### [ Python ] 在此範例中，您會使用 `loads`函數來執行二進位轉換。 ``` proof_text = proof_response.get('Proof').get('IonText') proof_hashes = loads(proof_text) ``` ------ ## 步驟 4：從修訂重新計算摘要使用驗證雜湊清單重新計算摘要，從修訂雜湊開始。只要先前儲存的摘要在 QLDB 之外已知且受信任，如果重新計算的摘要雜湊符合儲存的摘要雜湊，就會證明文件修訂的完整性。 ------ #### [ Java ] ``` // Calculate digest byte[] calculatedDigest = internalHashes.stream().reduce(hash.getBytes(), BlockHashVerification::dot); boolean verified = Arrays.equals(expectedDigest, calculatedDigest); if (verified) { System.out.printf("Successfully verified document revision for id '%s'!%n", metadataId); } else { System.out.printf("Document revision for id '%s' verification failed!%n", metadataId); return; } ``` ------ #### [ .NET ] ``` byte[] documentHash = hash.Bytes().ToArray(); foreach (IIonValue proofHash in proofValue.GetElementAt(0)) { // Calculate the digest documentHash = Dot(documentHash, proofHash.Bytes().ToArray()); } bool verified = expectedDigest.SequenceEqual(documentHash); if (verified) { Console.WriteLine($"Successfully verified document revision for id '{metadataId}'!"); } else { Console.WriteLine($"Document revision for id '{metadataId}' verification failed!"); return; } ``` ------ #### [ Go ] ``` // Going through nodes and calculate digest for reader.Next() { val, _ := reader.ByteValue() documentHash, err = dot(documentHash, val) } // Compare documentHash with the expected digest verified := reflect.DeepEqual(documentHash, expectedDigest) if verified { fmt.Printf("Successfully verified document revision for id '%s'!\n", metadataId) } else { fmt.Printf("Document revision for id '%s' verification failed!\n", metadataId) return } ``` ------ #### [ Node.js ] ``` let documentHash: Uint8Array = hash.uInt8ArrayValue(); proofValue.elements().forEach((proofHash: dom.Value) => { // Calculate the digest documentHash = dot(documentHash, proofHash.uInt8ArrayValue()); }); let verified: boolean = isEqual(expectedDigest, documentHash); if (verified) { console.log(`Successfully verified document revision for id '${metadataId}'!`); } else { console.log(`Document revision for id '${metadataId}' verification failed!`); return; } ``` ------ #### [ Python ] ``` # Calculate digest calculated_digest = reduce(dot, proof_hashes, document_hash) verified = calculated_digest == expected_digest if verified: print("Successfully verified document revision for id '{}'!".format(metadata_id)) else: print("Document revision for id '{}' verification failed!".format(metadata_id)) ``` ------ ## 步驟 5：請求日誌區塊的證明接著，您要驗證包含文件修訂的日誌區塊。使用您在[步驟 1](#verification.tutorial.step-1) 中儲存的摘要中的區塊地址和提示地址來提交`GetBlock`請求。與[步驟 2](#verification.tutorial.step-2) 中的`GetRevision`請求類似，*您必須再次提供已儲存摘要中的提示地址，以取得區塊的證明。*此 API 操作會傳回包含區塊的物件，以及區塊的證明。如需日誌區塊結構及其內容的資訊，請參閱 [Amazon QLDB 中的日誌內容](journal-contents.md)。 ------ #### [ Java ] ``` // Submit a request for the block GetBlockRequest getBlockRequest = new GetBlockRequest() .withName(ledgerName) .withBlockAddress(new ValueHolder().withIonText(blockAddressText)) .withDigestTipAddress(digestResult.getDigestTipAddress()); // Get a result back GetBlockResult getBlockResult = client.getBlock(getBlockRequest); ``` ------ #### [ .NET ] ``` // Submit a request for the block GetBlockRequest getBlockRequest = new GetBlockRequest { Name = ledgerName, BlockAddress = new ValueHolder { IonText = blockAddressText }, DigestTipAddress = getDigestResponse.DigestTipAddress }; // Get a response back GetBlockResponse getBlockResponse = client.GetBlockAsync(getBlockRequest).Result; ``` ------ #### [ Go ] ``` // Submit a request for the block blockInput := qldb.GetBlockInput{ Name: ¤tLedgerName, BlockAddress: &qldb.ValueHolder{IonText: &blockAddress}, DigestTipAddress: digestOutput.DigestTipAddress, } // Get a result back blockOutput, err := client.GetBlock(&blockInput) if err != nil { panic(err) } ``` ------ #### [ Node.js ] ``` // Submit a request for the block const getBlockRequest: GetBlockRequest = { Name: ledgerName, BlockAddress: { IonText: dumpText(blockAddress) }, DigestTipAddress: getDigestResponse.DigestTipAddress }; // Get a response back const getBlockResponse: GetBlockResponse = await qldbClient.getBlock(getBlockRequest).promise(); ``` ------ #### [ Python ] ``` def block_address_to_dictionary(ion_dict): """ Convert a block address from IonPyDict into a dictionary. Shape of the dictionary must be: {'IonText': "{strandId: <"strandId">, sequenceNo: }"} :type ion_dict: :py:class:`amazon.ion.simple_types.IonPyDict`/str :param ion_dict: The block address value to convert. :rtype: dict :return: The converted dict. """ block_address = {'IonText': {}} if not isinstance(ion_dict, str): py_dict = '{{strandId: "{}", sequenceNo:{}}}'.format(ion_dict['strandId'], ion_dict['sequenceNo']) ion_dict = py_dict block_address['IonText'] = ion_dict return block_address # Submit a request for the block and get a result back block_response = qldb_client.get_block(Name=ledger_name, BlockAddress=block_address_to_dictionary(block_address), DigestTipAddress=digest_tip_address) ``` ------ 然後，從結果中擷取區塊雜湊和驗證。 ------ #### [ Java ] 在此範例中，您使用將區塊物件`IonLoader`載入 `IonDatagram`容器。 ``` String blockText = getBlockResult.getBlock().getIonText(); IonDatagram datagram = SYSTEM.getLoader().load(blockText); ionStruct = (IonStruct)datagram.get(0); final byte[] blockHash = ((IonBlob)ionStruct.get("blockHash")).getBytes(); ``` 您也可以使用將證明`IonLoader`載入 `IonDatagram`。 ``` proofText = getBlockResult.getProof().getIonText(); // Take the proof and create a list of hash binary data datagram = SYSTEM.getLoader().load(proofText); ListIterator listIter = ((IonList)datagram.iterator().next()).listIterator(); internalHashes.clear(); while (listIter.hasNext()) { internalHashes.add(((IonBlob)listIter.next()).getBytes()); } ``` ------ #### [ .NET ] 在此範例中，您使用 `IonLoader`將區塊和證明載入每個區塊的 Ion 資料包。 ``` string blockText = getBlockResponse.Block.IonText; IIonDatagram blockValue = IonLoader.Default.Load(blockText); // blockValue is a IonDatagram, and the first value is an IonStruct containing the blockHash byte[] blockHash = blockValue.GetElementAt(0).GetField("blockHash").Bytes().ToArray(); proofText = getBlockResponse.Proof.IonText; proofValue = IonLoader.Default.Load(proofText); ``` ------ #### [ Go ] 在此範例中，您使用 Ion 讀取器將驗證轉換為二進位，並逐一查看驗證的節點雜湊清單。 ``` proofText = blockOutput.Proof.IonText block := new(map[string]interface{}) err = ion.UnmarshalString(*blockOutput.Block.IonText, block) if err != nil { panic(err) } blockHash := (*block)["blockHash"].([]byte) // Use ion.Reader to iterate over the proof's node hashes reader = ion.NewReaderString(*proofText) // Enter the struct containing node hashes reader.Next() if err := reader.StepIn(); err != nil { panic(err) } ``` ------ #### [ Node.js ] 在此範例中，您可以使用 `load`函數將區塊和證明轉換為二進位。 ``` const blockValue: dom.Value = load(getBlockResponse.Block.IonText) let blockHash: Uint8Array = blockValue.get("blockHash").uInt8ArrayValue(); proofValue = load(getBlockResponse.Proof.IonText); ``` ------ #### [ Python ] 在此範例中，您可以使用 `loads`函數將區塊和證明轉換為二進位。 ``` block_text = block_response.get('Block').get('IonText') block = loads(block_text) block_hash = block.get('blockHash') proof_text = block_response.get('Proof').get('IonText') proof_hashes = loads(proof_text) ``` ------ ## 步驟 6：從區塊重新計算摘要使用驗證雜湊清單重新計算摘要，從區塊雜湊開始。只要先前儲存的摘要在 QLDB 之外已知且受信任，如果重新計算的摘要雜湊符合儲存的摘要雜湊，就會證明區塊的完整性。 ------ #### [ Java ] ``` // Calculate digest calculatedDigest = internalHashes.stream().reduce(blockHash, BlockHashVerification::dot); verified = Arrays.equals(expectedDigest, calculatedDigest); if (verified) { System.out.printf("Block address '%s' successfully verified!%n", blockAddressText); } else { System.out.printf("Block address '%s' verification failed!%n", blockAddressText); } ``` ------ #### [ .NET ] ``` foreach (IIonValue proofHash in proofValue.GetElementAt(0)) { // Calculate the digest blockHash = Dot(blockHash, proofHash.Bytes().ToArray()); } verified = expectedDigest.SequenceEqual(blockHash); if (verified) { Console.WriteLine($"Block address '{blockAddressText}' successfully verified!"); } else { Console.WriteLine($"Block address '{blockAddressText}' verification failed!"); } ``` ------ #### [ Go ] ``` // Going through nodes and calculate digest for reader.Next() { val, err := reader.ByteValue() if err != nil { panic(err) } blockHash, err = dot(blockHash, val) } // Compare blockHash with the expected digest verified = reflect.DeepEqual(blockHash, expectedDigest) if verified { fmt.Printf("Block address '%s' successfully verified!\n", blockAddress) } else { fmt.Printf("Block address '%s' verification failed!\n", blockAddress) return } ``` ------ #### [ Node.js ] ``` proofValue.elements().forEach((proofHash: dom.Value) => { // Calculate the digest blockHash = dot(blockHash, proofHash.uInt8ArrayValue()); }); verified = isEqual(expectedDigest, blockHash); if (verified) { console.log(`Block address '${dumpText(blockAddress)}' successfully verified!`); } else { console.log(`Block address '${dumpText(blockAddress)}' verification failed!`); } ``` ------ #### [ Python ] ``` # Calculate digest calculated_digest = reduce(dot, proof_hashes, block_hash) verified = calculated_digest == expected_digest if verified: print("Block address '{}' successfully verified!".format(dumps(block_address, binary=False, omit_version_marker=True))) else: print("Block address '{}' verification failed!".format(block_address)) ``` ------ 先前的程式碼範例會在重新計算摘要時使用下列`dot`函數。此函數會取得兩個雜湊的輸入、排序它們、串連它們，然後傳回串連陣列的雜湊。 ------ #### [ Java ] ``` /** * Takes two hashes, sorts them, concatenates them, and then returns the * hash of the concatenated array. * * @param h1 * Byte array containing one of the hashes to compare. * @param h2 * Byte array containing one of the hashes to compare. * @return the concatenated array of hashes. */ public static byte[] dot(final byte[] h1, final byte[] h2) { if (h1.length != HASH_LENGTH || h2.length != HASH_LENGTH) { throw new IllegalArgumentException("Invalid hash."); } int byteEqual = 0; for (int i = h1.length - 1; i >= 0; i--) { byteEqual = Byte.compare(h1[i], h2[i]); if (byteEqual != 0) { break; } } byte[] concatenated = new byte[h1.length + h2.length]; if (byteEqual < 0) { System.arraycopy(h1, 0, concatenated, 0, h1.length); System.arraycopy(h2, 0, concatenated, h1.length, h2.length); } else { System.arraycopy(h2, 0, concatenated, 0, h2.length); System.arraycopy(h1, 0, concatenated, h2.length, h1.length); } MessageDigest messageDigest; try { messageDigest = MessageDigest.getInstance("SHA-256"); } catch (NoSuchAlgorithmException e) { throw new IllegalStateException("SHA-256 message digest is unavailable", e); } messageDigest.update(concatenated); return messageDigest.digest(); } ``` ------ #### [ .NET ] ``` ///

/// Takes two hashes, sorts them, concatenates them, and then returns the /// hash of the concatenated array. ///

/// Byte array containing one of the hashes to compare. /// Byte array containing one of the hashes to compare. /// The concatenated array of hashes. private static byte[] Dot(byte[] h1, byte[] h2) { if (h1.Length == 0) { return h2; } if (h2.Length == 0) { return h1; } HashAlgorithm hashAlgorithm = HashAlgorithm.Create("SHA256"); HashComparer comparer = new HashComparer(); if (comparer.Compare(h1, h2) < 0) { return hashAlgorithm.ComputeHash(h1.Concat(h2).ToArray()); } else { return hashAlgorithm.ComputeHash(h2.Concat(h1).ToArray()); } } private class HashComparer : IComparer { private static readonly int HASH_LENGTH = 32; public int Compare(byte[] h1, byte[] h2) { if (h1.Length != HASH_LENGTH || h2.Length != HASH_LENGTH) { throw new ArgumentException("Invalid hash"); } for (var i = h1.Length - 1; i >= 0; i--) { var byteEqual = (sbyte)h1[i] - (sbyte)h2[i]; if (byteEqual != 0) { return byteEqual; } } return 0; } } static void Main() { // Get a digest GetDigestRequest getDigestRequest = new GetDigestRequest { Name = ledgerName }; GetDigestResponse getDigestResponse = client.GetDigestAsync(getDigestRequest).Result; // expectedDigest is the buffer we will use later to compare against our calculated digest MemoryStream digest = getDigestResponse.Digest; byte[] expectedDigest = digest.ToArray(); // Retrieve info for the given vin's document revisions var result = driver.Execute(txn => { string query = $"SELECT blockAddress, hash, metadata.id FROM _ql_committed_{tableName} WHERE data.VIN = '{vin}'"; return txn.Execute(query); }); Console.WriteLine($"Verifying document revisions for vin '{vin}' in table '{tableName}' in ledger '{ledgerName}'"); foreach (IIonValue ionValue in result) { IIonStruct ionStruct = ionValue; // Get the requested fields IIonValue blockAddress = ionStruct.GetField("blockAddress"); IIonBlob hash = ionStruct.GetField("hash"); String metadataId = ionStruct.GetField("id").StringValue; Console.WriteLine($"Verifying document revision for id '{metadataId}'"); // Use an Ion Reader to convert block address to text IIonReader reader = IonReaderBuilder.Build(blockAddress); StringWriter sw = new StringWriter(); IIonWriter textWriter = IonTextWriterBuilder.Build(sw); textWriter.WriteValues(reader); string blockAddressText = sw.ToString(); // Submit a request for the revision GetRevisionRequest revisionRequest = new GetRevisionRequest { Name = ledgerName, BlockAddress = new ValueHolder { IonText = blockAddressText }, DocumentId = metadataId, DigestTipAddress = getDigestResponse.DigestTipAddress }; // Get a response back GetRevisionResponse revisionResponse = client.GetRevisionAsync(revisionRequest).Result; string proofText = revisionResponse.Proof.IonText; IIonDatagram proofValue = IonLoader.Default.Load(proofText); byte[] documentHash = hash.Bytes().ToArray(); foreach (IIonValue proofHash in proofValue.GetElementAt(0)) { // Calculate the digest documentHash = Dot(documentHash, proofHash.Bytes().ToArray()); } bool verified = expectedDigest.SequenceEqual(documentHash); if (verified) { Console.WriteLine($"Successfully verified document revision for id '{metadataId}'!"); } else { Console.WriteLine($"Document revision for id '{metadataId}' verification failed!"); return; } // Submit a request for the block GetBlockRequest getBlockRequest = new GetBlockRequest { Name = ledgerName, BlockAddress = new ValueHolder { IonText = blockAddressText }, DigestTipAddress = getDigestResponse.DigestTipAddress }; // Get a response back GetBlockResponse getBlockResponse = client.GetBlockAsync(getBlockRequest).Result; string blockText = getBlockResponse.Block.IonText; IIonDatagram blockValue = IonLoader.Default.Load(blockText); // blockValue is a IonDatagram, and the first value is an IonStruct containing the blockHash byte[] blockHash = blockValue.GetElementAt(0).GetField("blockHash").Bytes().ToArray(); proofText = getBlockResponse.Proof.IonText; proofValue = IonLoader.Default.Load(proofText); foreach (IIonValue proofHash in proofValue.GetElementAt(0)) { // Calculate the digest blockHash = Dot(blockHash, proofHash.Bytes().ToArray()); } verified = expectedDigest.SequenceEqual(blockHash); if (verified) { Console.WriteLine($"Block address '{blockAddressText}' successfully verified!"); } else { Console.WriteLine($"Block address '{blockAddressText}' verification failed!"); } } } } } ``` ------ #### [ Go ] ``` package main import ( "context" "crypto/sha256" "errors" "fmt" "reflect" "github.com/amzn/ion-go/ion" "github.com/aws/aws-sdk-go/aws" AWSSession "github.com/aws/aws-sdk-go/aws/session" "github.com/aws/aws-sdk-go/service/qldb" "github.com/aws/aws-sdk-go/service/qldbsession" "github.com/awslabs/amazon-qldb-driver-go/qldbdriver" ) const ( hashLength = 32 ledgerName = "vehicle-registration" tableName = "VehicleRegistration" vin = "KM8SRDHF6EU074761" ) // Takes two hashes, sorts them, concatenates them, and then returns the hash of the concatenated array. func dot(h1, h2 []byte) ([]byte, error) { compare, err := hashComparator(h1, h2) if err != nil { return nil, err } var concatenated []byte if compare < 0 { concatenated = append(h1, h2...) } else { concatenated = append(h2, h1...) } newHash := sha256.Sum256(concatenated) return newHash[:], nil } func hashComparator(h1 []byte, h2 []byte) (int16, error) { if len(h1) != hashLength || len(h2) != hashLength { return 0, errors.New("invalid hash") } for i := range h1 { // Reverse index for little endianness index := hashLength - 1 - i // Handle byte being unsigned and overflow h1Int := int16(h1[index]) h2Int := int16(h2[index]) if h1Int > 127 { h1Int = 0 - (256 - h1Int) } if h2Int > 127 { h2Int = 0 - (256 - h2Int) } difference := h1Int - h2Int if difference != 0 { return difference, nil } } return 0, nil } func main() { driverSession := AWSSession.Must(AWSSession.NewSession(aws.NewConfig())) qldbSession := qldbsession.New(driverSession) driver, err := qldbdriver.New(ledgerName, qldbSession, func(options *qldbdriver.DriverOptions) {}) if err != nil { panic(err) } client := qldb.New(driverSession) // Get a digest currentLedgerName := ledgerName input := qldb.GetDigestInput{Name: ¤tLedgerName} digestOutput, err := client.GetDigest(&input) if err != nil { panic(err) } // expectedDigest is the buffer we will later use to compare against our calculated digest expectedDigest := digestOutput.Digest // Retrieve info for the given vin's document revisions result, err := driver.Execute(context.Background(), func(txn qldbdriver.Transaction) (interface{}, error) { statement := fmt.Sprintf( "SELECT blockAddress, hash, metadata.id FROM _ql_committed_%s WHERE data.VIN = '%s'", tableName, vin) result, err := txn.Execute(statement) if err != nil { return nil, err } results := make([]map[string]interface{}, 0) // Convert the result set into a map for result.Next(txn) { var doc map[string]interface{} err := ion.Unmarshal(result.GetCurrentData(), &doc) if err != nil { return nil, err } results = append(results, doc) } return results, nil }) if err != nil { panic(err) } resultSlice := result.([]map[string]interface{}) fmt.Printf("Verifying document revisions for vin '%s' in table '%s' in ledger '%s'\n", vin, tableName, ledgerName) for _, value := range resultSlice { // Get the requested fields ionBlockAddress, err := ion.MarshalText(value["blockAddress"]) if err != nil { panic(err) } blockAddress := string(ionBlockAddress) metadataId := value["id"].(string) documentHash := value["hash"].([]byte) fmt.Printf("Verifying document revision for id '%s'\n", metadataId) // Submit a request for the revision revisionInput := qldb.GetRevisionInput{ BlockAddress: &qldb.ValueHolder{IonText: &blockAddress}, DigestTipAddress: digestOutput.DigestTipAddress, DocumentId: &metadataId, Name: ¤tLedgerName, } // Get a result back revisionOutput, err := client.GetRevision(&revisionInput) if err != nil { panic(err) } proofText := revisionOutput.Proof.IonText // Use ion.Reader to iterate over the proof's node hashes reader := ion.NewReaderString(*proofText) // Enter the struct containing node hashes reader.Next() if err := reader.StepIn(); err != nil { panic(err) } // Going through nodes and calculate digest for reader.Next() { val, _ := reader.ByteValue() documentHash, err = dot(documentHash, val) } // Compare documentHash with the expected digest verified := reflect.DeepEqual(documentHash, expectedDigest) if verified { fmt.Printf("Successfully verified document revision for id '%s'!\n", metadataId) } else { fmt.Printf("Document revision for id '%s' verification failed!\n", metadataId) return } // Submit a request for the block blockInput := qldb.GetBlockInput{ Name: ¤tLedgerName, BlockAddress: &qldb.ValueHolder{IonText: &blockAddress}, DigestTipAddress: digestOutput.DigestTipAddress, } // Get a result back blockOutput, err := client.GetBlock(&blockInput) if err != nil { panic(err) } proofText = blockOutput.Proof.IonText block := new(map[string]interface{}) err = ion.UnmarshalString(*blockOutput.Block.IonText, block) if err != nil { panic(err) } blockHash := (*block)["blockHash"].([]byte) // Use ion.Reader to iterate over the proof's node hashes reader = ion.NewReaderString(*proofText) // Enter the struct containing node hashes reader.Next() if err := reader.StepIn(); err != nil { panic(err) } // Going through nodes and calculate digest for reader.Next() { val, err := reader.ByteValue() if err != nil { panic(err) } blockHash, err = dot(blockHash, val) } // Compare blockHash with the expected digest verified = reflect.DeepEqual(blockHash, expectedDigest) if verified { fmt.Printf("Block address '%s' successfully verified!\n", blockAddress) } else { fmt.Printf("Block address '%s' verification failed!\n", blockAddress) return } } } ``` ------ #### [ Node.js ] ``` import { QldbDriver, Result, TransactionExecutor} from "amazon-qldb-driver-nodejs"; import { QLDB } from "aws-sdk" import { GetBlockRequest, GetBlockResponse, GetDigestRequest, GetDigestResponse, GetRevisionRequest, GetRevisionResponse } from "aws-sdk/clients/qldb"; import { createHash } from "crypto"; import { dom, dumpText, load } from "ion-js" const ledgerName: string = "vehicle-registration"; const tableName: string = "VehicleRegistration"; const vin: string = "KM8SRDHF6EU074761"; const driver: QldbDriver = new QldbDriver(ledgerName); const qldbClient: QLDB = new QLDB(); const HASH_SIZE = 32; /** * Takes two hashes, sorts them, concatenates them, and calculates a digest based on the concatenated hash. * @param h1 Byte array containing one of the hashes to compare. * @param h2 Byte array containing one of the hashes to compare. * @returns The digest calculated from the concatenated hash values. */ function dot(h1: Uint8Array, h2: Uint8Array): Uint8Array { if (h1.length === 0) { return h2; } if (h2.length === 0) { return h1; } const newHashLib = createHash("sha256"); let concatenated: Uint8Array; if (hashComparator(h1, h2) < 0) { concatenated = concatenate(h1, h2); } else { concatenated = concatenate(h2, h1); } newHashLib.update(concatenated); return newHashLib.digest(); } /** * Compares two hashes by their **signed** byte values in little-endian order. * @param hash1 The hash value to compare. * @param hash2 The hash value to compare. * @returns Zero if the hash values are equal, otherwise return the difference of the first pair of non-matching * bytes. * @throws RangeError When the hash is not the correct hash size. */ function hashComparator(hash1: Uint8Array, hash2: Uint8Array): number { if (hash1.length !== HASH_SIZE || hash2.length !== HASH_SIZE) { throw new RangeError("Invalid hash."); } for (let i = hash1.length-1; i >= 0; i--) { const difference: number = (hash1[i]<<24 >>24) - (hash2[i]<<24 >>24); if (difference !== 0) { return difference; } } return 0; } /** * Helper method that concatenates two Uint8Array. * @param arrays List of arrays to concatenate, in the order provided. * @returns The concatenated array. */ function concatenate(...arrays: Uint8Array[]): Uint8Array { let totalLength = 0; for (const arr of arrays) { totalLength += arr.length; } const result = new Uint8Array(totalLength); let offset = 0; for (const arr of arrays) { result.set(arr, offset); offset += arr.length; } return result; } /** * Helper method that checks for equality between two Uint8Array. * @param expected Byte array containing one of the hashes to compare. * @param actual Byte array containing one of the hashes to compare. * @returns Boolean indicating equality between the two Uint8Array. */ function isEqual(expected: Uint8Array, actual: Uint8Array): boolean { if (expected === actual) return true; if (expected == null || actual == null) return false; if (expected.length !== actual.length) return false; for (let i = 0; i < expected.length; i++) { if (expected[i] !== actual[i]) { return false; } } return true; } const main = async function (): Promise { // Get a digest const getDigestRequest: GetDigestRequest = { Name: ledgerName }; const getDigestResponse: GetDigestResponse = await qldbClient.getDigest(getDigestRequest).promise(); // expectedDigest is the buffer we will later use to compare against our calculated digest const expectedDigest: Uint8Array = getDigestResponse.Digest; const result: dom.Value[] = await driver.executeLambda(async (txn: TransactionExecutor): Promise => { const query: string = `SELECT blockAddress, hash, metadata.id FROM _ql_committed_${tableName} WHERE data.VIN = '${vin}'`; const queryResult: Result = await txn.execute(query); return queryResult.getResultList(); }); console.log(`Verifying document revisions for vin '${vin}' in table '${tableName}' in ledger '${ledgerName}'`); for (let value of result) { // Get the requested fields const blockAddress: dom.Value = value.get("blockAddress"); const hash: dom.Value = value.get("hash"); const metadataId: string = value.get("id").stringValue(); console.log(`Verifying document revision for id '${metadataId}'`); // Submit a request for the revision const revisionRequest: GetRevisionRequest = { Name: ledgerName, BlockAddress: { IonText: dumpText(blockAddress) }, DocumentId: metadataId, DigestTipAddress: getDigestResponse.DigestTipAddress }; // Get a response back const revisionResponse: GetRevisionResponse = await qldbClient.getRevision(revisionRequest).promise(); let proofValue: dom.Value = load(revisionResponse.Proof.IonText); let documentHash: Uint8Array = hash.uInt8ArrayValue(); proofValue.elements().forEach((proofHash: dom.Value) => { // Calculate the digest documentHash = dot(documentHash, proofHash.uInt8ArrayValue()); }); let verified: boolean = isEqual(expectedDigest, documentHash); if (verified) { console.log(`Successfully verified document revision for id '${metadataId}'!`); } else { console.log(`Document revision for id '${metadataId}' verification failed!`); return; } // Submit a request for the block const getBlockRequest: GetBlockRequest = { Name: ledgerName, BlockAddress: { IonText: dumpText(blockAddress) }, DigestTipAddress: getDigestResponse.DigestTipAddress }; // Get a response back const getBlockResponse: GetBlockResponse = await qldbClient.getBlock(getBlockRequest).promise(); const blockValue: dom.Value = load(getBlockResponse.Block.IonText) let blockHash: Uint8Array = blockValue.get("blockHash").uInt8ArrayValue(); proofValue = load(getBlockResponse.Proof.IonText); proofValue.elements().forEach((proofHash: dom.Value) => { // Calculate the digest blockHash = dot(blockHash, proofHash.uInt8ArrayValue()); }); verified = isEqual(expectedDigest, blockHash); if (verified) { console.log(`Block address '${dumpText(blockAddress)}' successfully verified!`); } else { console.log(`Block address '${dumpText(blockAddress)}' verification failed!`); } } }; if (require.main === module) { main(); } ``` ------ #### [ Python ] ``` from amazon.ion.simpleion import dumps, loads from array import array from boto3 import client from functools import reduce from hashlib import sha256 from pyqldb.driver.qldb_driver import QldbDriver ledger_name = 'vehicle-registration' table_name = 'VehicleRegistration' vin = 'KM8SRDHF6EU074761' qldb_client = client('qldb') hash_length = 32 def query_doc_revision(txn): query = "SELECT blockAddress, hash, metadata.id FROM _ql_committed_{} WHERE data.VIN = '{}'".format(table_name, vin) return txn.execute_statement(query) def block_address_to_dictionary(ion_dict): """ Convert a block address from IonPyDict into a dictionary. Shape of the dictionary must be: {'IonText': "{strandId: <"strandId">, sequenceNo: }"} :type ion_dict: :py:class:`amazon.ion.simple_types.IonPyDict`/str :param ion_dict: The block address value to convert. :rtype: dict :return: The converted dict. """ block_address = {'IonText': {}} if not isinstance(ion_dict, str): py_dict = '{{strandId: "{}", sequenceNo:{}}}'.format(ion_dict['strandId'], ion_dict['sequenceNo']) ion_dict = py_dict block_address['IonText'] = ion_dict return block_address def dot(hash1, hash2): """ Takes two hashes, sorts them, concatenates them, and then returns the hash of the concatenated array. :type hash1: bytes :param hash1: The hash value to compare. :type hash2: bytes :param hash2: The hash value to compare. :rtype: bytes :return: The new hash value generated from concatenated hash values. """ if len(hash1) != hash_length or len(hash2) != hash_length: raise ValueError('Illegal hash.') hash_array1 = array('b', hash1) hash_array2 = array('b', hash2) difference = 0 for i in range(len(hash_array1) - 1, -1, -1): difference = hash_array1[i] - hash_array2[i] if difference != 0: break if difference < 0: concatenated = hash1 + hash2 else: concatenated = hash2 + hash1 new_hash_lib = sha256() new_hash_lib.update(concatenated) new_digest = new_hash_lib.digest() return new_digest # Get a digest get_digest_response = qldb_client.get_digest(Name=ledger_name) # expected_digest is the buffer we will later use to compare against our calculated digest expected_digest = get_digest_response.get('Digest') digest_tip_address = get_digest_response.get('DigestTipAddress') qldb_driver = QldbDriver(ledger_name=ledger_name) # Retrieve info for the given vin's document revisions result = qldb_driver.execute_lambda(query_doc_revision) print("Verifying document revisions for vin '{}' in table '{}' in ledger '{}'".format(vin, table_name, ledger_name)) for value in result: # Get the requested fields block_address = value['blockAddress'] document_hash = value['hash'] metadata_id = value['id'] print("Verifying document revision for id '{}'".format(metadata_id)) # Submit a request for the revision and get a result back proof_response = qldb_client.get_revision(Name=ledger_name, BlockAddress=block_address_to_dictionary(block_address), DocumentId=metadata_id, DigestTipAddress=digest_tip_address) proof_text = proof_response.get('Proof').get('IonText') proof_hashes = loads(proof_text) # Calculate digest calculated_digest = reduce(dot, proof_hashes, document_hash) verified = calculated_digest == expected_digest if verified: print("Successfully verified document revision for id '{}'!".format(metadata_id)) else: print("Document revision for id '{}' verification failed!".format(metadata_id)) # Submit a request for the block and get a result back block_response = qldb_client.get_block(Name=ledger_name, BlockAddress=block_address_to_dictionary(block_address), DigestTipAddress=digest_tip_address) block_text = block_response.get('Block').get('IonText') block = loads(block_text) block_hash = block.get('blockHash') proof_text = block_response.get('Proof').get('IonText') proof_hashes = loads(proof_text) # Calculate digest calculated_digest = reduce(dot, proof_hashes, block_hash) verified = calculated_digest == expected_digest if verified: print("Block address '{}' successfully verified!".format(dumps(block_address, binary=False, omit_version_marker=True))) else: print("Block address '{}' verification failed!".format(block_address)) ``` ------