  PGP is built upon a Distributed Web of Trust in which the trustworthiness of
a user is established by others who can vouch through a digital signature for
that particular identity. Preventing its wholesale adoption are a number of
inherent weaknesses to include (but not limited to) the following: 1) Trust
Relationships are built on a subjective honor system, 2) Only first degree
relationships can be fully trusted, 3) Levels of trust are difficult to
quantify with actual values, and 4) Issues with the Web of Trust itself
(Certification and Endorsement). Although the security that PGP provides is
proven to be reliable, it has largely failed to garner large scale adoption. In
this paper, we propose several novel contributions to address the
aforementioned issues with PGP and associated Web of Trust. To address the
subjectivity of the Web of Trust, we provide a new certificate format based on
Bitcoin which allows a user to verify a PGP certificate using Bitcoin
identity-verification transactions - forming first degree trust relationships
that are tied to actual values (i.e., number of Bitcoins transferred during
transaction). Secondly, we present the design of a novel Distributed PGP key
server that leverages the Bitcoin transaction blockchain to store and retrieve
Bitcoin-Based PGP certificates. Lastly, we provide a web prototype application
that demonstrates several of these capabilities in an actual environment.
