In this thesis, we investigate three areas of cryptography: searchable encryption, reputation systems, and cryptographic cloud architectures. We mostly investigate these areas from fairly distinct perspectives. However, we find applications for the three concepts in crowd work, and suggest combining aspects of the concepts into a single cryptographic scheme tailored to the crowd work setting. Regarding searchable encryption, we formally define the desired security notions and provide schemes satisfying these notions. Among others, we propose the first searchable encryption scheme that simultaneously provides fine-grained access control in a multi-reader and multi-writer setting, is dynamic, forward private, and verifiable. Concerning reputation systems, we propose a novel security notion, a variant of rater anonymity, motivated by the crowd work scenario. We then propose a very simple reputation system that satisfies our anonymity notion, as well as the security requirements typically imposed on reputation systems. With respect to cloud architectures, we address the trust and security issues in the cloud at the most fundamental level, the internal structure of the cloud. Our proposal relies on hardware security as a trust anchor for the cloud and enables parties to outsource computations on their secret cryptographic keys to the cloud without cloud service providers learning these keys.