Feat: select disclosure for present (openwallet-foundation#153)

Signed-off-by: Lukas <Lukas@hopae.io>
Signed-off-by: Mirko Mollik <mirko.mollik@fit.fraunhofer.de>
Co-authored-by: Mirko Mollik <mirko.mollik@fit.fraunhofer.de>

packages/present/src/present.ts

@@ -3,7 +3,7 @@ import {
   type PresentationFrame,
   SD_SEPARATOR,
 } from '@sd-jwt/types';
-import type { Disclosure } from '@sd-jwt/utils';
+import { Disclosure, SDJWTException } from '@sd-jwt/utils';
 import {
   createHashMapping,
   decodeSdJwt,
@@ -13,6 +13,7 @@ import {
   createHashMappingSync,
   decodeSdJwtSync,
   unpackSync,
+  unpackObj,
 } from '@sd-jwt/decode';
 import type { HasherSync } from '@sd-jwt/types/src/type';
 
@@ -138,3 +139,73 @@ export const transformPresentationFrame = <T extends object>(
     return acc;
   }, []);
 };
+
+export type SerializedDisclosure = {
+  digest: string;
+  encoded: string;
+  salt: string;
+  key: string | undefined;
+  value: unknown;
+};
+
+const createHashMappingForSerializedDisclosure = (
+  disclosures: SerializedDisclosure[],
+) => {
+  const map: Record<string, Disclosure> = {};
+  for (let i = 0; i < disclosures.length; i++) {
+    const disclosure = disclosures[i];
+    const { digest, encoded, key, salt, value } = disclosure;
+    // we made Disclosure to fit the interface of unpack
+    map[digest] = Disclosure.fromArray(
+      key ? [salt, key, value] : [salt, value],
+      { digest, encoded },
+    );
+  }
+  return map;
+};
+
+/**
+ * This function selects the serialized disclosures from the payload
+ * and array of serialized disclosure based on the presentation frame.
+ * If you want to know what is serialized disclosures, check type SerializedDisclosure.
+ * @param payload: Record<string, unknown>
+ * @param disclosures: SerializedDisclosure[]
+ * @param presentationFrame: PresentationFrame<T>
+ */
+export const selectDisclosures = <T extends Record<string, unknown>>(
+  payload: Record<string, unknown>,
+  disclosures: SerializedDisclosure[],
+  presentationFrame: PresentationFrame<T>,
+) => {
+  if (disclosures.length === 0) {
+    return [];
+  }
+
+  const hashmap = createHashMappingForSerializedDisclosure(disclosures);
+  const { disclosureKeymap } = unpackObj(payload, hashmap);
+  const keys = transformPresentationFrame(presentationFrame);
+
+  const presentedDisclosures = keys
+    .map((k) => hashmap[disclosureKeymap[k]])
+    .filter((d) => d !== undefined);
+
+  const selectedDisclosures: SerializedDisclosure[] = presentedDisclosures.map(
+    (d) => {
+      const { salt, key, value, _digest } = d;
+      if (!_digest) {
+        throw new SDJWTException(
+          'Implementation error: _digest is not defined',
+        );
+      }
+      return {
+        digest: _digest,
+        encoded: d.encode(),
+        salt,
+        key,
+        value,
+      };
+    },
+  );
+
+  return selectedDisclosures;
+};

packages/present/src/test/present.spec.ts

@@ -1,10 +1,12 @@
 import { describe, expect, test } from 'vitest';
 import { digest } from '@sd-jwt/crypto-nodejs';
 import {
+  type SerializedDisclosure,
   present,
   presentSync,
   presentableKeys,
   presentableKeysSync,
+  selectDisclosures,
   transformPresentationFrame,
 } from '../index';
 import { decodeSdJwt, decodeSdJwtSync } from '@sd-jwt/decode';
@@ -149,4 +151,155 @@ describe('Present tests', () => {
     const list = transformPresentationFrame<typeof claims>(obj);
     expect(list).toStrictEqual(['address', 'address.city', 'address.street']);
   });
+
+  test('select disclosures', () => {
+    const payload = {
+      lastname: 'Doe',
+      _sd: [
+        'COnqXH7wGBFGR1ao12sDwTfu84Zs7cq92CZIg8ulIuU',
+        'RrOc4ZfBVyD6iNlMbtmdokZOti322mOXfvIOBKvpuc4',
+        'aXqInKwHoE1l8OM1VNUQDqTPeNUG1cMJVwVbxZJpP14',
+      ],
+      _sd_alg: 'SHA-256',
+    };
+
+    const presentationFrame = {
+      firstname: true,
+      //ssn: true,
+      id: true,
+    };
+
+    const disclosures: SerializedDisclosure[] = [
+      {
+        digest: 'COnqXH7wGBFGR1ao12sDwTfu84Zs7cq92CZIg8ulIuU',
+        encoded: 'WyJiMDQ3NjBiOTgxMDgyM2ZhIiwiZmlyc3RuYW1lIiwiSm9obiJd',
+        salt: 'b04760b9810823fa',
+        key: 'firstname',
+        value: 'John',
+      },
+      {
+        digest: 'RrOc4ZfBVyD6iNlMbtmdokZOti322mOXfvIOBKvpuc4',
+        encoded: 'WyJjNTQwZWE4YjJhOTNmZDE1Iiwic3NuIiwiMTIzLTQ1LTY3ODkiXQ',
+        salt: 'c540ea8b2a93fd15',
+        key: 'ssn',
+        value: '123-45-6789',
+      },
+      {
+        digest: 'aXqInKwHoE1l8OM1VNUQDqTPeNUG1cMJVwVbxZJpP14',
+        encoded: 'WyI5N2YwNTVkZTk0NGFmNzI5IiwiaWQiLCIxMjM0Il0',
+        salt: '97f055de944af729',
+        key: 'id',
+        value: '1234',
+      },
+    ];
+
+    const selected = selectDisclosures(payload, disclosures, presentationFrame);
+    expect(selected).toStrictEqual([
+      {
+        digest: 'COnqXH7wGBFGR1ao12sDwTfu84Zs7cq92CZIg8ulIuU',
+        encoded: 'WyJiMDQ3NjBiOTgxMDgyM2ZhIiwiZmlyc3RuYW1lIiwiSm9obiJd',
+        salt: 'b04760b9810823fa',
+        key: 'firstname',
+        value: 'John',
+      },
+      {
+        digest: 'aXqInKwHoE1l8OM1VNUQDqTPeNUG1cMJVwVbxZJpP14',
+        encoded: 'WyI5N2YwNTVkZTk0NGFmNzI5IiwiaWQiLCIxMjM0Il0',
+        salt: '97f055de944af729',
+        key: 'id',
+        value: '1234',
+      },
+    ]);
+  });
+
+  test('select disclosures no input', () => {
+    const selected = selectDisclosures({}, [], {});
+    expect(selected).toStrictEqual([]);
+  });
+
+  test('select disclosures noting return', () => {
+    const payload = {
+      lastname: 'Doe',
+      _sd: [
+        'COnqXH7wGBFGR1ao12sDwTfu84Zs7cq92CZIg8ulIuU',
+        'RrOc4ZfBVyD6iNlMbtmdokZOti322mOXfvIOBKvpuc4',
+        'aXqInKwHoE1l8OM1VNUQDqTPeNUG1cMJVwVbxZJpP14',
+      ],
+      _sd_alg: 'SHA-256',
+    };
+
+    const presentationFrame = {};
+
+    const disclosures: SerializedDisclosure[] = [
+      {
+        digest: 'COnqXH7wGBFGR1ao12sDwTfu84Zs7cq92CZIg8ulIuU',
+        encoded: 'WyJiMDQ3NjBiOTgxMDgyM2ZhIiwiZmlyc3RuYW1lIiwiSm9obiJd',
+        salt: 'b04760b9810823fa',
+        key: 'firstname',
+        value: 'John',
+      },
+      {
+        digest: 'RrOc4ZfBVyD6iNlMbtmdokZOti322mOXfvIOBKvpuc4',
+        encoded: 'WyJjNTQwZWE4YjJhOTNmZDE1Iiwic3NuIiwiMTIzLTQ1LTY3ODkiXQ',
+        salt: 'c540ea8b2a93fd15',
+        key: 'ssn',
+        value: '123-45-6789',
+      },
+      {
+        digest: 'aXqInKwHoE1l8OM1VNUQDqTPeNUG1cMJVwVbxZJpP14',
+        encoded: 'WyI5N2YwNTVkZTk0NGFmNzI5IiwiaWQiLCIxMjM0Il0',
+        salt: '97f055de944af729',
+        key: 'id',
+        value: '1234',
+      },
+    ];
+    const selected = selectDisclosures(payload, disclosures, presentationFrame);
+    expect(selected).toStrictEqual([]);
+  });
+
+  test('expect missing digest', () => {
+    const payload = {
+      lastname: 'Doe',
+      _sd: [
+        'COnqXH7wGBFGR1ao12sDwTfu84Zs7cq92CZIg8ulIuU',
+        'RrOc4ZfBVyD6iNlMbtmdokZOti322mOXfvIOBKvpuc4',
+        'aXqInKwHoE1l8OM1VNUQDqTPeNUG1cMJVwVbxZJpP14',
+      ],
+      _sd_alg: 'SHA-256',
+    };
+
+    const presentationFrame = {
+      firstname: true,
+      //ssn: true,
+      id: true,
+    };
+
+    const disclosures: SerializedDisclosure[] = [
+      //@ts-ignore
+      {
+        encoded: 'WyJiMDQ3NjBiOTgxMDgyM2ZhIiwiZmlyc3RuYW1lIiwiSm9obiJd',
+        salt: 'b04760b9810823fa',
+        key: 'firstname',
+        value: 'John',
+      },
+      {
+        digest: 'RrOc4ZfBVyD6iNlMbtmdokZOti322mOXfvIOBKvpuc4',
+        encoded: 'WyJjNTQwZWE4YjJhOTNmZDE1Iiwic3NuIiwiMTIzLTQ1LTY3ODkiXQ',
+        salt: 'c540ea8b2a93fd15',
+        key: 'ssn',
+        value: '123-45-6789',
+      },
+      {
+        digest: 'aXqInKwHoE1l8OM1VNUQDqTPeNUG1cMJVwVbxZJpP14',
+        encoded: 'WyI5N2YwNTVkZTk0NGFmNzI5IiwiaWQiLCIxMjM0Il0',
+        salt: '97f055de944af729',
+        key: 'id',
+        value: '1234',
+      },
+    ];
+
+    expect(() =>
+      selectDisclosures(payload, disclosures, presentationFrame),
+    ).toThrowError('Implementation error: _digest is not defined');
+  });
 });