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| 1 | +# Walkthrough for Android |
| 2 | + |
| 3 | +--8<---- |
| 4 | +/snippets/intro-infrastructure.md |
| 5 | +/snippets/intro-use-case.md |
| 6 | +--8<---- |
| 7 | + |
| 8 | +## Technical requirements |
| 9 | + |
| 10 | +You can run this example on your local machine, or you can use our Gitpod setup to bootstrap a full development environment. If running locally, you'll only need Java (TODO - Specify exact recent version) installed |
| 11 | + |
| 12 | +## Sample Project |
| 13 | + |
| 14 | +Clone this sdk repository: [trinsic-id/sdk-examples](https://github.com/trinsic-id/sdk-examples) |
| 15 | + |
| 16 | +In this project, we'll be following along the `/android/app/src/main/java/id/trinsic/android/DriversLicenseDemo.kt` |
| 17 | + |
| 18 | + |
| 19 | +## Configure services |
| 20 | + |
| 21 | +Create a reference to the wallet service that points to your ecosystem service. You should have received this URL with your ecosystem setup. |
| 22 | + |
| 23 | +```kotlin |
| 24 | +val config = TrinsicUtilities.getConfigFromUrl("https://staging-internal.trinsic.cloud:443") |
| 25 | +val accountService = AccountService(null, config) |
| 26 | + |
| 27 | +val walletService = WalletService(null, config) |
| 28 | +val credentialsService = CredentialsService(null, config) |
| 29 | +``` |
| 30 | + |
| 31 | +## Setup wallet profiles |
| 32 | + |
| 33 | +Let's create three different profiles, each pointing to a separate wallet. Since we are using a single console app for this demo, we will simply set the active profile before each interaction to designate which actor is currently taking action. |
| 34 | +To create a new wallet profile, we use the [Create Wallet](../reference/services/wallet-service/#create-wallet) feature. |
| 35 | + |
| 36 | +```kotlin |
| 37 | +fun setupActors() { |
| 38 | + // SETUP ACTORS |
| 39 | + allison = accountService.signIn(null).profile |
| 40 | + motorVehicleDepartment = accountService.signIn(null).profile |
| 41 | + policeOfficer = accountService.signIn(null).profile |
| 42 | +} |
| 43 | +``` |
| 44 | + |
| 45 | +If you would like to save the profile for future use, you can simply export the serialized profile to a local storage. Please note that the profiles contain sensitive key data, so they should be stored in a secure enclave. |
| 46 | + |
| 47 | +Read more about [security profiles](../reference/index.md#authorization) and authentication. |
| 48 | + |
| 49 | +## Certificate issuance |
| 50 | + |
| 51 | +Upon receiving her driver's license, Allison also receives a digital certificate from the DMV. This certificate is digitally signed by the DMV, acting as an issuer. |
| 52 | +The certificate is in a JSON form, and for this example, we will use the following JSON. This file is found in `android/app/src/main/assets/drivers-license-unsigned.json`. |
| 53 | + |
| 54 | +```json |
| 55 | +{ |
| 56 | + "@context": [ |
| 57 | + "https://www.w3.org/2018/credentials/v1", |
| 58 | + "https://w3id.org/vdl/v1", |
| 59 | + "https://w3id.org/security/bbs/v1" |
| 60 | + ], |
| 61 | + "type": [ |
| 62 | + "VerifiableCredential", |
| 63 | + "Iso18013DriversLicenseCredential" |
| 64 | + ], |
| 65 | + "credentialSubject": { |
| 66 | + "id": "did:key:z6MkhdEKMp6Buh8tPB1BV5etVkqx32q5nbVmzWPLpWSHyshm", |
| 67 | + "license": { |
| 68 | + "type": "Iso18013DriversLicense", |
| 69 | + "document_number": "542426814", |
| 70 | + "family_name": "TURNER", |
| 71 | + "given_name": "SUSAN", |
| 72 | + "birth_date": "1998-08-28", |
| 73 | + "issue_date": "2018-01-15T10:00:00Z", |
| 74 | + "expiry_date": "2022-08-27T12:00:00Z", |
| 75 | + "issuing_country": "US", |
| 76 | + "issuing_authority": "UT", |
| 77 | + "un_distinguishing_sign": "USA" |
| 78 | + } |
| 79 | + } |
| 80 | +} |
| 81 | +``` |
| 82 | + |
| 83 | +Let's set the active profile to the DMV, and call the issuance endpoint |
| 84 | + |
| 85 | +```kotlin |
| 86 | +fun issueCredential(credentialString: String): HashMap<*, *>? { |
| 87 | + // ISSUE CREDENTIAL |
| 88 | + credentialsService.profile = motorVehicleDepartment |
| 89 | + val credentialJson = Gson().fromJson( |
| 90 | + credentialString, |
| 91 | + java.util.HashMap::class.java |
| 92 | + ) |
| 93 | + val credential = credentialsService.issueCredential(credentialJson) |
| 94 | + println("Credential: $credential") |
| 95 | + |
| 96 | + return credential |
| 97 | +} |
| 98 | +``` |
| 99 | + |
| 100 | +At this point, the DMV can send the signed credential to Allison using any available methods. These methods can include any message exchange protocol, or a custom transport. In this case, we'll assume that the credential was delivered to Allison in an offline environment. |
| 101 | + |
| 102 | +## Store certificate in personal wallet |
| 103 | + |
| 104 | +Allison can store this credential in her cloud wallet, simply by calling the [Insert Item](../reference/services/wallet-service/#insert-record) function. |
| 105 | + |
| 106 | +```kotlin |
| 107 | +fun saveCredential(credential: HashMap<*, *>): String { |
| 108 | + // STORE CREDENTIAL |
| 109 | + walletService.profile = allison |
| 110 | + val itemId = walletService.insertItem(credential) |
| 111 | + println("item id = $itemId") |
| 112 | + |
| 113 | + return itemId |
| 114 | +} |
| 115 | +``` |
| 116 | + |
| 117 | +## Proof of Driver's License |
| 118 | + |
| 119 | +If Allison is ever stopped by a police officer, she must show her driver's license. The request for this proof also comes in a form of JSON frame. |
| 120 | +This request can be communicated using any exchange protocol. Again, we'll assume this was done offline. |
| 121 | + |
| 122 | +Let's save this request in a file named `drivers-license-frame.json` |
| 123 | + |
| 124 | +```json |
| 125 | +{ |
| 126 | + "@context": [ |
| 127 | + "https://www.w3.org/2018/credentials/v1", |
| 128 | + "https://w3id.org/vdl/v1", |
| 129 | + "https://w3id.org/security/bbs/v1" |
| 130 | + ], |
| 131 | + "type": [ |
| 132 | + "VerifiableCredential", |
| 133 | + "Iso18013DriversLicenseCredential" |
| 134 | + ], |
| 135 | + "credentialSubject": { |
| 136 | + "@explicit": true, |
| 137 | + "license": { |
| 138 | + "type": "Iso18013DriversLicense", |
| 139 | + "@explicit": true, |
| 140 | + "birth_date": {}, |
| 141 | + "document_number": {}, |
| 142 | + "expiry_date": {}, |
| 143 | + "issuing_authority": {} |
| 144 | + } |
| 145 | + } |
| 146 | +} |
| 147 | +``` |
| 148 | + |
| 149 | +This request asks Allison to provide proof of a valid driver's license, including the `issuing_authority`, `birth_date`, `expiry_number`, and `document_number` fields. |
| 150 | + |
| 151 | +Allison can use the [Create Proof](../reference/services/wallet-service/#create-proof) functions to build a proof that will share only the requested fields. |
| 152 | + |
| 153 | +```kotlin |
| 154 | +fun createProof(credentialFrameString: String, itemId: String): HashMap<*,*> { |
| 155 | + // SHARE CREDENTIAL |
| 156 | + credentialsService.profile = allison |
| 157 | + val proofRequestJson = Gson().fromJson( |
| 158 | + credentialFrameString, |
| 159 | + java.util.HashMap::class.java |
| 160 | + ) |
| 161 | + val credentialProof = credentialsService.createProof(itemId, proofRequestJson) |
| 162 | + println("Proof: {credential_proof}") |
| 163 | + return credentialProof |
| 164 | +} |
| 165 | +``` |
| 166 | + |
| 167 | +## Verification |
| 168 | + |
| 169 | +Allison shares the proof of credential she created with the police officer. The officer can now use [Verify Proof](../reference/services/wallet-service/#verify-proof) functions to check the validity of the proof. |
| 170 | + |
| 171 | +```kotlin |
| 172 | +fun verifyProof(credentialProof: HashMap<*,*>): Boolean { |
| 173 | + // VERIFY CREDENTIAL |
| 174 | + credentialsService.profile = policeOfficer |
| 175 | + return credentialsService.verifyProof(credentialProof) |
| 176 | +} |
| 177 | +``` |
| 178 | + |
| 179 | +## Complete sample code |
| 180 | + |
| 181 | +This sample is available in our [GitHub](https://github.com/trinsic-id/sdk-examples/blob/main/android/app/src/main/java/id/trinsic/android/) repo. |
| 182 | + |
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