Currency security and forensics: a survey

By its definition, the word currency refers to an agreed medium for exchange, a nation’s currency is the formal medium enforced by the elected governing entity. Throughout history, issuers have faced one common threat: counterfeiting. Despite technological advancements, overcoming counterfeit production remains a distant future. Scientific determination of authenticity requires a deep understanding of the raw materials and manufacturing processes involved. This survey serves as a synthesis of the current literature to understand the technology and the mechanics involved in currency manufacture and security, whilst identifying gaps in the current literature. Ultimately, a robust currency is desire

New authentication applications in the protection of caller ID and banknote

In the era of computers and the Internet, where almost everything is interconnected, authentication plays a crucial role in safeguarding online and offline data. As authentication systems face continuous testing from advanced attacking techniques and tools, the need for evolving authentication technology becomes imperative. In this thesis, we study attacks on authentication systems and propose countermeasures. Considering various nominated techniques, the thesis is divided into two parts. The first part introduces caller ID verification (CIV) protocol to address caller ID spoofing in telecommunication systems. This kind of attack usually follows fraud, which not only inflicts financial losses on victims but also reduces public trust in the telephone system. We propose CIV to authenticate the caller ID based on a challenge-response process. We show that spoofing can be leveraged, in conjunction with dual tone multi-frequency (DTMF), to efficiently implement the challenge-response process, i.e., using spoofing to fight against spoofing. We conduct extensive experiments showing that our solution can work reliably across the legacy and new telephony systems, including landline, cellular and Internet protocol (IP) network, without the cooperation of telecom providers. In the second part, we present polymer substrate fingerprinting (PSF) as a method to combat counterfeiting of banknotes in the financial area. Our technique is built on the observation that the opacity coating leaves uneven thickness in the polymer substrate, resulting in random translucent patterns when a polymer banknote is back-lit by a light source. With extensive experiments, we show that our method can reliably authenticate banknotes and is robust against rough daily handling of banknotes. Furthermore, we show that the extracted fingerprints are extremely scalable to identify every polymer note circulated globally. Our method ensures that even when counterfeiters have procured the same printing equipment and ink as used by a legitimate government, counterfeiting banknotes remains infeasible

How to Issue a Central Bank Digital Currency

With the emergence of Bitcoin and recently proposed stablecoins from BigTechs, such as Diem (formerly Libra), central banks face growing competition from private actors offering their own digital alternative to physical cash. We do not address the normative question whether a central bank should issue a central bank digital currency (CBDC) or not. Instead, we contribute to the current research debate by showing how a central bank could do so, if desired. We propose a token-based system without distributed ledger technology and show how earlier-deployed, software-only electronic cash can be improved upon to preserve transaction privacy, meet regulatory requirements in a compelling way, and offer a level of quantum-resistant protection against systemic privacy risk. Neither monetary policy nor financial stability would be materially affected because a CBDC with this design would replicate physical cash rather than bank deposits

How to Issue a Central Bank Digital Currency

With the emergence of Bitcoin and recently proposed stablecoins from BigTechs, such as Diem (formerly Libra), central banks face growing competition from private actors offering their own digital alternative to physical cash. We do not address the normative question whether a central bank should issue a central bank digital currency (CBDC) or not. Instead, we contribute to the current research debate by showing how a central bank could do so, if desired. We propose a token-based system without distributed ledger technology and show how earlier-deployed, software-only electronic cash can be improved upon to preserve transaction privacy, meet regulatory requirements in a compelling way, and offer a level of quantum-resistant protection against systemic privacy risk. Neither monetary policy nor financial stability would be materially affected because a CBDC with this design would replicate physical cash rather than bank deposits.Comment: Swiss National Bank Working Paper3/202

Texture to the Rescue : Practical Paper Fingerprinting based on Texture Patterns

In this article, we propose a novel paper fingerprinting technique based on analyzing the translucent patterns revealed when a light source shines through the paper. These patterns represent the inherent texture of paper, formed by the random interleaving of wooden particles during the manufacturing process. We show that these patterns can be easily captured by a commodity camera and condensed into a compact 2,048-bit fingerprint code. Prominent works in this area (Nature 2005, IEEE S&P 2009, CCS 2011) have all focused on fingerprinting paper based on the paper "surface." We are motivated by the observation that capturing the surface alone misses important distinctive features such as the noneven thickness, random distribution of impurities, and different materials in the paper with varying opacities. Through experiments, we demonstrate that the embedded paper texture provides a more reliable source for fingerprinting than features on the surface. Based on the collected datasets, we achieve 0% false rejection and 0% false acceptance rates. We further report that our extracted fingerprints contain 807 degrees of freedom (DoF), which is much higher than the 249 DoF with iris codes (that have the same size of 2,048 bits). The high amount of DoF for texturebased fingerprints makes our method extremely scalable for recognition among very large databases; it also allows secure usage of the extracted fingerprint in privacy-preserving authentication schemes based on error correction techniques

KAIME : Central Bank Digital Currency with Realistic and Modular Privacy

Recently, with the increasing interest in Central Bank Digital Currency (CBDC), many countries have been working on researching and developing digital currency. The most important reasons for this interest are that CBDC eliminates the disadvantages of traditional currencies and provides a safer, faster, and more efficient payment system. These benefits also come with challenges, such as safeguarding individuals’ privacy and ensuring regulatory mechanisms. While most researches address the privacy conflict between users and regulatory agencies, they miss an important detail. Important parts of a financial system are banks and financial institutions. Some studies ignore the need for privacy and include these institutions in the CBDC system, no system currently offers a solution to the privacy conflict between banks, financial institutions, and users. In this study, while we offer a solution to the privacy conflict between the user and the regulatory agencies, we also provide a solution to the privacy conflict between the user and the banks. Our solution, KAIME has also a modular structure. The privacy of the sender and receiver can be hidden if desired. Compared to previous related research, security analysis and implementation of KAIME is substantially simpler because simple and well-known cryptographic methods are used

Digital watermarking and novel security devices

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