This paper is to explore applications of the blockchain technology to the concept of “proof of X” such as proof of identity, proof of property ownership, proof of specific transaction, proof of college degree, proof of medical records, proof of academic achievements, etc. It describes a novel approach of building a decentralized transparent immutable secure personal archive management and service system. Personal archive is defined as a collection of various artifacts that reflect personal portfolio as well as personal unique identifications. Personal portfolio is beyond of a statement of personal achievement. It is an evidentiary document designed to provide qualitative and quantitative chronically documents and examples. Subjects can tag their information with proof, that is, certified by trusted entities or organizations like universities. Such proofs are associated with confidentiality levels exposed in the public domains. Personal identifications include biometrics as well as other multi-factors such as something the subject “has”, the subject “knows” or the subject “acts”. Stack holders in a consortium oriented blockchain network serve as verifiers and /or miners that provide their trusted services the delegated proof of stake. Such personal archive based system can be exploited to various applications including professional network like Linkedin, instant credit approval like alipay or live human from social bots like internet social media. A prototype simulation shows that such personal portfolio management and service system is feasible and immune to many ID attacks.
Personal archive service system (PASS) is defined as a collection of digital artifacts as well as a collection of service tools. A personal digital artifact (PDA) is a digital form of personal achievements with evidentiary documents (PAE) or of personal identifications (PID) that can be used to uniquely identify a person. Examples of PAE are such as personal education, experiences, training, degree, diploma, academic transcripts and various certificates. Personal wealth like property value, bank balance, investments can also be examples of PAE. Typical examples of PID are biometric measures from the person like finger prints, iris and vein. Other information known only to the person, physical objects owned by the person can be examples of PID. Behavior patterns, personal reflection and characteristics are also considered as examples of PID.
The collection of PAEs are similar to personal portfolio (PP). It is associated with timeline that assembles a specific characteristics of a person. PP is distinct from resume in that it is more of inclusive and expanding than a line of statements in resume.
To be useful and trustful, these PDAs need to be verified by a third party who should have direct knowledge of these claimed artifacts. For example, a university can provide official transcripts to their graduates. A landlord is able to provide a letter of reference to their tenants. No other entities can do that.
We define various roles in this process. We use the term “subject” to be a person or a user who is building his or her collection of PDAs, “certifier” to be an institute or an entity that provides certification, “inquisitor” to be an agent or organization who provides service of investigation and obtaining relevant proof of any particular subject, and “client” to a person or organization using professional services provided by “inquisitor”. For example, for a potential candidate to be hired by a company, the candidate is a subject, the company is a client who needs to hire a third party to verify all the information provided by the subject. The third party is the inquisitor and the company is a client of the inquisitor. The inquisitor needs to contact various certifiers such as universities who gain education, companies who used to work, or organizations who issue other certifications.
This process of verifying PDAs by inquisitors is often time consuming. It is also repeated every time a client makes a request. In some cases, it obtains information beyond the consent given by the subject. Therefore, it poses a threat of privacy. Moreover, it is essentially a model of centralized system that can potentially cause a point of failure, a point of bottleneck, a point of confusion and a point of abuse. For example, clearance for teaching when hiring an adjunct by a third party takes time. In some extreme cases we have experienced that the semester starts while the clearance is still pending. Another example is about name change by a subject. Without revealing its previous name used, the subject is hard to get verified. We see a case that a subject wants an institution to issue a new diploma due to name change. It is usually a mission impossible task although in this case the subject has all other IDs that remain the same just name difference.
But, the process of verification is becoming increasing necessary and a must. We have observed resume padding is becoming more epidemic . Resume padding is to add false or exaggerated information to a resume to enhance credentials for a job. More than 40% of resumes inflates their salary, 33% inaccurate job description, 29% altered employment dates, 27% falsified references, and 21% fraudulent degrees. Hence, we can image that the burden of requiring verification is very heavy.
Recently, blockchain technology, first introduced in bitcoin  as an innovative payment network and a new kind of money, is being applied to financial related industrials. Many other fields such as supply chain, manufacture, Internet of Things are exploiting it as well. [21-22 for example]. The key features from using the blockchain technology are its decentralized, consensus based shared ledger, smart contract, high transparency yet high privacy. The idea to have secure storage and transmission of digitally signed documents with a super audit trail in immutable document exchange networks is emerging in trade finance, shipping, and insurance, where everyone has the same demand to validate the identity of people and assets. It does not need a third party as an intermediary or authority for verification, cleaning house or any other purposes. It is being used in building a secure anonymous yet transparent immutable ID Service .
Personal Archive Service System (PASS) proposed in this paper is to use blockchain technology to exploit its desirable features such as immutable, transparency, anonymous and public consensus. The subject controls its own PDAs and makes decision to whom to release. Figure 1 illustrates the general infrastructure and architecture view of a PASS under blockchain. The subject, represented by icon has its own repository or wallet that aggregates all its relevant PDAs. The certifiers issue certificates to its owners as well as to a trusted network. It does such certificates once for everyone involved and should not be bothered anymore. There is no need to have a third party or an inquisitor. They also pass the certificates to a consortium oriented block chain network that the trust is developed in a delegated proof of stake. A client makes a request to the subject and gain access to those granted PDAs.