In the absence of data protection measures, software applications lead to privacy breaches, posing threats to end-users and software organisations. Privacy Enhancing Technologies (PETs) are technical measures that protect personal data, thus minimising such privacy breaches. However, for software applications to deliver data protection using PETs, software developers should actively and correctly incorporate PETs into the software they develop. Therefore, to uncover ways to encourage and support developers to embed PETs into software, this Systematic Literature Review (SLR) analyses 39 empirical studies on developers' privacy practices. It reports the usage of six PETs in software application scenarios. Then, it discusses challenges developers face when integrating PETs into software, ranging from intrinsic challenges, such as the unawareness of PETs, to extrinsic challenges, such as the increased development cost. Next, the SLR presents the existing solutions to address these challenges, along with the limitations of the solutions. Further, it outlines future research avenues to better understand PETs from a developer perspective and minimise the challenges developers face when incorporating PETs into software.

翻译：在缺乏数据保护措施的情况下，软件应用程序会导致隐私泄露，给终端用户和软件机构带来威胁。隐私增强技术（PETs）是保护个人数据的技术手段，可最大限度地减少此类隐私泄露。然而，为了使软件应用程序利用PETs实现数据保护，软件开发者应主动且正确地将PETs融入其开发的软件中。因此，为探索鼓励并支持开发者将PETs嵌入软件的方法，本系统性文献综述（SLR）分析了39项关于开发者隐私实践的实证研究。该综述报告了六种PETs在软件应用场景中的使用情况；随后讨论了开发者在集成PETs时面临的挑战——涵盖从对PETs缺乏认知等内在挑战，到开发成本增加等外在挑战；接着呈现了应对这些挑战的现有解决方案及其局限性；最后，从开发者视角提出未来研究方向，以期更深入地理解PETs，并减少开发者将PETs融入软件时面临的挑战。