Selective Disclosure in Self-Sovereign Identity based on Hashed Values

Every person has associated a set of attributes that need to be shown to perform daily operations, such as the ones in personal identity card. The Self Sovereign Identity framework brings this to the digital world, giving to the user full responsibility of their own attributes. Each user receives a set of attributes is paired with as a Verifiable Credential, which could be issued, for example, by a municipality as a digitally signed ID card. However, it is not possible to disclose only one attribute of the ID card without invalidating the signature, therefore Selective Disclosure approaches have been defined to address this problem. This paper describes a selective disclosure method based on hashing, showing that the method is secure and applicable to the real world due to its low requirement in terms of space and time to create and verify a credential.