Create sdjwt challenge

src/services/common/signatures/SDJWT.md

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+# Selective Disclosure
+
+Selective disclosure enables a Holder of a Verifiable Credential to choose which pieces of information will be revealed to a Verifier. This gives the Holder more flexibility and enables them to only share the information needed by the recipient without having to claim multiple atomic credentials.
+
+There are different ways of performing selective disclosure with Verifiable Credentials including BBS+ signatures and SD-JWT. In this challenge we would like to explore implementing the SD-JWT spec. However, other selective disclosure implementations are welcome.
+
+**Goal**: Provide support for creating a Verifiable Credential represented as a JWT that supports selective disclosure of claim values conforming to the SD-JWT spec.
+
+## Spec
+
+### SD-JWT
+
+A [Selective Disclosure JSON Web Token (SD-JWT)](https://www.ietf.org/archive/id/draft-ietf-oauth-selective-disclosure-jwt-04.html) is a type of JSON Web Token in which the claims in the body are hashed, making them unreadable without disclosure. 
+The original values of the claims can only be revealed by providing the necessary disclosures.
+
+* [Shorter explanation]( https://api-pilot.ebsi.eu/docs/specs/guidelines/selective-disclosure-sd-jwt) of spec from EBSI
+* [Reference Implementation](https://github.com/christianpaquin/sd-jwt)
+
+### Functionality to Implement
+To complete this challenge, the below should be implemented:
+* Functions to support Issuance of SD-JWT Verifiable Credential by an Issuer
+* Functions to support Presentation of an SD-JWT Verifiable Credential from the Holder to a Verifier
+* Functions to support Verification of an SD-JWT Verifiable Credential by a Verifier
+
+## Where to Start/Implementation Details
+
+A [`sdjwt.ts`](sdjwt.ts) starter file has been created to implement the sd-jwt spec for issuance, presentation, and verification of a selective disclosure Verifiable Credential
+
+### Issuance of SD-JWT
+1. Issuer creates Verifiable Credential as usual
+2. Issuer transforms Credential into an SD-JWT
+3. Issuer sends SD-JWT and all disclosures to holder
+
+#### Transfomation of VC into SD-JWT
+1. all or some of claims transformed into disclosures (salt + attributename + given value)
+2. disclosure converted to base64 string
+3. disclosure put into hash function
+4. the hashed disclosured are what gets included in the SD-JWT in `_sd` jwt field of credentialSubject
+
+Example sd-jwt:
+"eyJ0eXAiOiJKV1QiLCJhbGciOiJFUzI1NiIsImtpZCI6ImRpZDplYnNpOnp2SFdYMzU5QTNDdmZKbkNZYUFpQWRlI0YwcjVPeXRfbGFodnZ6Nk1XbFlzM21jWU5LWmlpUWRVZnF2OHRzaEhOOXcifQ.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.wC1jmebWUSVQYO18DluQhYUbTXDpvWuBSQv3apiiP3OdHlyPMRmFjX7jWPshjaWQkasuL_DBJ-IQufgDzT8z7Q~WyIyR0xDNDJzS1F2ZUNmR2ZyeU5STjl3IiwgImZhbWlseU5hbWUiLCAiQ2Fycm9sbCJd~WyJlbHVWNU9nM2dTTklJOEVZbnN4QV9BIiwgImdpdmVuTmFtZSIsICJMZXdpcyJd~WyI2SWo3dE0tYTVpVlBHYm9TNXRtdlZBIiwgImJpcnRoRGF0ZSIsICIxODMyLTAxLTI3Il0"
+
+### Presenting a SD-JWT
+1. Holder shares the SD-JWT with concatenated disclosures appended to JWT by ~
+
+### Verifying a SD-JWT
+1. Verifier receives disclosures and SD-JWT
+2. Confirms that shared disclosures are part of SD-JWT by hashing the received disclosures and comparing the hashed values with the values present in SD-JWT
+
+## Testing
+The functionality added for this challenge should be unit tested. Tests can be added [here](../../../../tests/unit/signatures)
+
+## Criteria For Completion
+* All [functionality](#Functionality-to-Implement) has been implemented
+* Code written has corresponding unit tests (90% coverage)
+* Code is well documented
+* Code passes CI github action (building, linting, and testing of SDK)