{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,6]],"date-time":"2025-11-06T05:15:53Z","timestamp":1762406153304,"version":"build-2065373602"},"reference-count":85,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2025,10,31]],"date-time":"2025-10-31T00:00:00Z","timestamp":1761868800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Internal Security Fund of the European Union","award":["MIS: 6002910"],"award-info":[{"award-number":["MIS: 6002910"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCP"],"abstract":"<jats:p>Hashes are vital in limiting the spread of child sexual abuse material online, yet their use introduces unresolved technical, legal, and ethical challenges. This paper bridges a critical gap by analyzing both cryptographic and perceptual hashing, not only in terms of detection capabilities, but also their vulnerabilities and implications for privacy governance. Unlike prior work, it reframes CSAM detection as a multidimensional issue, at the intersection of cybersecurity, data protection law, and digital ethics. Three key contributions are made: first, a comparative evaluation of hashing techniques, revealing weaknesses, such as susceptibility to media edits, collision attacks, hash inversion, and data leakage; second, a call for standardized benchmarks and interoperable evaluation protocols to assess system robustness; and third, a legal argument that perceptual hashes qualify as personal data under EU law, with implications for transparency and accountability. Ethically, the paper underscores the tension faced by service providers in balancing user privacy with the duty to detect CSAM. It advocates for detection systems that are not only technically sound, but also legally defensible and ethically governed. By integrating technical analysis with legal insight, this paper offers a comprehensive framework for evaluating CSAM detection, within the broader context of digital safety and privacy.<\/jats:p>","DOI":"10.3390\/jcp5040092","type":"journal-article","created":{"date-parts":[[2025,11,3]],"date-time":"2025-11-03T19:30:27Z","timestamp":1762198227000},"page":"92","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Hashing in the Fight Against CSAM: Technology at the Crossroads of Law and Ethics"],"prefix":"10.3390","volume":"5","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3056-1311","authenticated-orcid":false,"given":"Evangelia","family":"Daskalaki","sequence":"first","affiliation":[{"name":"Institute of Computer Science, Foundation for Research and Technology, P.O. Box 1385 Heraklion, Crete, Greece"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-9982-7699","authenticated-orcid":false,"given":"Emmanouela","family":"Kokolaki","sequence":"additional","affiliation":[{"name":"Institute of Computer Science, Foundation for Research and Technology, P.O. Box 1385 Heraklion, Crete, Greece"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7134-9029","authenticated-orcid":false,"given":"Paraskevi","family":"Fragopoulou","sequence":"additional","affiliation":[{"name":"Institute of Computer Science, Foundation for Research and Technology, P.O. Box 1385 Heraklion, Crete, Greece"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,10,31]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"\u00c1lvarez, D.P., Orozco, A.L.S., Garc\u00eda-Miguel, J.P., and Villalba, L.J.G. (2023). Learning Strategies for Sensitive Content Detection. Electronics, 12.","DOI":"10.3390\/electronics12112496"},{"key":"ref_2","unstructured":"Hellerman, H. (1967). Digital Computer System Principles Hardcover Herbert Hellerman, McGraw-Hill Companies."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"187","DOI":"10.1098\/rspb.1980.0020","article-title":"Theory of edge detection","volume":"207","author":"Marr","year":"1980","journal-title":"Proc. R. Soc. Lond. B Biol. Sci."},{"key":"ref_4","unstructured":"Venkatesan, R., Koon, S.-M., Jakubowski, M., and Moulin, P. (2000, January 10\u201313). Robust Image Hashing. Proceedings of the IEEE International Conference on Image Processing, Vancouver, BC, Canada."},{"key":"ref_5","unstructured":"Swaminathan, A., Mao, Y., and Wu, M. (2006, January 8\u201311). Perceptual Hash Functions for Image Authentication. Proceedings of the IEEE International Conference on Image Processing (ICIP 2006), Atlanta, GA, USA."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"3452","DOI":"10.1109\/TIP.2006.881948","article-title":"Perceptual Image Hashing Via Feature Points: Performance Evaluation and Tradeoffs","volume":"15","author":"Monga","year":"2006","journal-title":"IEEE Trans. Image Process."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"323","DOI":"10.1007\/s11741-007-0401-2","article-title":"Recent development of perceptual image hashing","volume":"11","year":"2007","journal-title":"J. Shanghai Univ."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"66","DOI":"10.1038\/scientificamerican0608-66","article-title":"Digital Image Forensics","volume":"298","author":"Farid","year":"2008","journal-title":"Sci. Am."},{"key":"ref_9","first-page":"593","article-title":"Reining in online abuses","volume":"19","author":"Farid","year":"2018","journal-title":"Technol. Innov."},{"key":"ref_10","first-page":"1","article-title":"An Overview of Perceptual Hashing","volume":"1","author":"Farid","year":"2021","journal-title":"J. Online Trust. Saf."},{"key":"ref_11","unstructured":"Singh, A., Khan, M.Z., Sharma, S., and Debnath, N.C. (2025, January 19\u201321). Perceptual Hashing Algorithms for Image Recognition. Proceedings of the 11th International Conference on Advanced Intelligent Systems and Informatics (AISI 2025), Port Said, Egypt."},{"key":"ref_12","unstructured":"Ofcom (2025, October 28). Overview of Perceptual Hashing Technology. Available online: https:\/\/www.ofcom.org.uk\/siteassets\/resources\/documents\/research-and-data\/online-research\/other\/perceptual-hashing-technology.pdf?v=328806."},{"key":"ref_13","unstructured":"Klinger, E., and Starkweather, D. (2025, October 28). pHash: The Open Source Perceptual Hash Library. Available online: https:\/\/phash.org\/."},{"key":"ref_14","unstructured":"Zauner, C. (2010). Implementation and Benchmarking of Perceptual Image Hash Functions. [Bachelor\u2019s Thesis, University of Applied Sciences Upper Austria]."},{"key":"ref_15","unstructured":"Buchner, J. (2025, October 28). ImageHash: Perceptual Image Hashing in Python. GitHub. Available online: https:\/\/github.com\/JohannesBuchner\/imagehash."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"McKeown, S., and Buchanan, W.J. (2023, January 21\u201324). Hamming Distributions of Popular Perceptual Hashing Techniques. Proceedings of the DFRWS EU 2023, Bonn, Germany.","DOI":"10.1016\/j.fsidi.2023.301509"},{"key":"ref_17","unstructured":"Hamadouche, M., Zebbiche, K., Guerroumi, M., Tebbi, H., and Zafoune, Y. (2021, January 25\u201326). The Comparative Study of Perceptual Hashing Algorithms: Application on Fingerprint Images. Proceedings of the 2nd International Conference on Computer Science\u2019s Complex Systems and their Applications (ICCSA 2021), Oum El-Bouaghi, Algeria."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"115713","DOI":"10.1016\/j.image.2019.115713","article-title":"Perceptual Hashing for Image Authentication: A Survey","volume":"81","author":"Du","year":"2020","journal-title":"Signal Process. Image Commun."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"203","DOI":"10.1016\/j.procs.2021.05.021","article-title":"Analysis of Perceptual Hashing Algorithms in Image Manipulation Detection","volume":"185","author":"Priyanka","year":"2021","journal-title":"Procedia Comput. Sci."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Alkhowaiter, M., Almubarak, K., and Zou, C. (2022, January 27\u201329). Evaluating Perceptual Hashing Algorithms in Detecting Image Manipulation Over Social Media Platforms. Proceedings of the 2022 IEEE International Conference on Cyber Security and Resilience (CSR), Rhodes, Greece.","DOI":"10.1109\/CSR54599.2022.9850288"},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Struppek, L., Hintersdorf, D., Neider, D., and Kersting, K. (2022, January 21\u201324). Learning to Break Deep Perceptual Hashing: The Use Case NeuralHash. Proceedings of the 2022 ACM Conference on Fairness, Accountability, and Transparency (FAccT 2022), Seoul, Republic of Korea.","DOI":"10.1145\/3531146.3533073"},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Roy, M., Meitei, T.D., and Pal, S. (2023, January 3\u20134). Various Approaches to Perceptual Image Hashing Systems\u2013A Survey. Proceedings of the IEEE International Symposium on Advanced Computing and Communication (ISACC 2023), Silchar, India.","DOI":"10.1109\/ISACC56298.2023.10083762"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Yang, B., Gu, F., Niu, X., and Huang, Y. (2006, January 18\u201320). Block Mean Value Based Image Perceptual Hashing. Proceedings of the International Conference on Intelligent Information Hiding and Multimedia Signal Processing (IIH-MSP), Pasadena, CA, USA.","DOI":"10.1109\/IIH-MSP.2006.265125"},{"key":"ref_24","unstructured":"Zeng, J. (2013). A novel Block-DCT and PCA based image perceptual hashing algorithm. arXiv."},{"key":"ref_25","unstructured":"Guo, X.C., and Hatzinakos, D. (2007, January 11\u201314). Content Based Image Hashing Via Wavelet and Radon Transform. Proceedings of the Advances in Multimedia Information Processing\u2013PCM 2007, Hong Kong, China."},{"key":"ref_26","first-page":"643S","article-title":"Perceptual Hashing for Color Images Using Invariant Moments","volume":"6","author":"Tang","year":"2012","journal-title":"Appl. Math. Inf. Sci."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"De Roover, C., De Vleeschouwer, C., Lefebvre, F., and Macq, B. (2005, January 14). Robust image hashing based on radial variance of pixels. Proceedings of the International Conference on Image Processing (ICIP), Genova, Italy.","DOI":"10.1109\/ICIP.2005.1530332"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Hernandez, R.A.P., Miyatake, M.N., and Kurkoski, B.M. (2011, January 7\u201310). Robust image hashing using image normalization and SVD decomposition. Proceedings of the IEEE International Midwest Symposium on Circuits and Systems (MWSCAS), Seoul, Republic of Korea.","DOI":"10.1109\/MWSCAS.2011.6026372"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"681906","DOI":"10.1117\/12.764846","article-title":"Security analysis of robust perceptual hashing","volume":"6819","author":"Koval","year":"2008","journal-title":"Proc. SPIE"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"123","DOI":"10.1145\/3572777","article-title":"Perceptual Hashing of Deep Convolutional Neural Networks for Model Copy Detection","volume":"19","author":"Chen","year":"2023","journal-title":"ACM Trans. Multimed. Comput. Commun. Appl."},{"key":"ref_31","unstructured":"Guo, J., and Li, J. (2015). CNN Based Hashing for Image Retrieval. arXiv."},{"key":"ref_32","unstructured":"Dalins, J., Wilson, C., and Boudry, D. (2019). PDQ & TMK + PDQF\u2013A Test Drive of Facebook\u2019s Perceptual Hashing Algorithms. arXiv."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Fernandez, P., Couairon, G., Jegou, H., Douze, M., and Furon, T. (2023, January 2\u20133). The Stable Signature: Rooting Watermarks in Latent Diffusion Models. Proceedings of the International Conference on Computer Vision (ICCV), Paris, France.","DOI":"10.1109\/ICCV51070.2023.02053"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"61","DOI":"10.1007\/s13735-018-0159-x","article-title":"A Review on Robust Video Copy Detection","volume":"8","author":"Wary","year":"2019","journal-title":"Int. J. Multimed. Inf. Retr."},{"key":"ref_35","unstructured":"(2025, October 28). META AI, TMK+PDQF Video Hashing Framework. GitHub. Available online: https:\/\/github.com\/facebook\/ThreatExchange\/tree\/main\/hashing\/tmk."},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"\u00c1smundsson, F.H., Lejsek, H., Da\u00f0ason, K., J\u00f3nsson, B.\u00de., and Amsaleg, L. (2009, January 23). Videntifier Forensic: Robust and Efficient Detection of Illegal Multimedia. Proceedings of the First ACM Workshop on Multimedia in Forensics, Beijing, China.","DOI":"10.1145\/1631272.1631488"},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Chen, H., Hu, C., Lee, F., Lin, C., Yao, W., Chen, L., and Chen, Q. (2021). A Supervised Video Hashing Method Based on a Deep 3D Convolutional Neural Network for Large-Scale Video Retrieval. Sensors, 21.","DOI":"10.3390\/s21093094"},{"key":"ref_38","unstructured":"Gayathri, M., Livitha, M., Surya, N., Ramya, M., and Surya, N. (2019). A Survey on Secured Video Transmission by Synchronisation and Hashing Technique. Int. J. Adv. Inf. Commun. Technol., 6, Available online: https:\/\/www.ijaict.com\/journals\/ijaict\/ijaict_pdf\/2019_volume06\/2019_v6i11\/ijaict%202017110301.pdf."},{"key":"ref_39","unstructured":"Morales, F., Sharma, S., Doan, C., and Levine, B. (2025, October 28). PHVSpec: A Benchmark-based Analysis of Perceptual Hash Systems for Videos. Tech. Coalit., Available online: https:\/\/paragonn-cdn.nyc3.cdn.digitaloceanspaces.com\/technologycoalition.org\/uploads\/Tech-Coalition-Video-Hash-Benchmark-Paper.pdf."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"147","DOI":"10.1002\/j.1538-7305.1950.tb00463.x","article-title":"Error detecting and error correcting codes","volume":"29","author":"Hamming","year":"1950","journal-title":"Bell Syst. Tech. J."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"12","DOI":"10.1109\/MSP.2015.2398954","article-title":"Euclidean Distance Matrices: Essential Theory, Algorithms and Applications","volume":"32","author":"Dokmanic","year":"2015","journal-title":"IEEE Signal Process. Mag."},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Connor, R. (2016, January 24\u201326). A Tale of Four Metrics. Proceedings of the Similarity Search and Applications (SISAP 2016), Tokyo, Japan.","DOI":"10.1007\/978-3-319-46759-7_16"},{"key":"ref_43","first-page":"301878","article-title":"Beyond Hamming Distance: Exploring spatial encoding in perceptual hashes","volume":"52","author":"McKeown","year":"2025","journal-title":"Forensic Sci. Int. Digit. Investig."},{"key":"ref_44","unstructured":"Menezes, A.J., van Oorschot, P.C., and Vanstone, S.A. (1996). Handbook of Applied Cryptography, CRC Press."},{"key":"ref_45","unstructured":"Rivest, R. (2025, October 28). The MD5 Message-Digest Algorithm. RFC Editor. Available online: http:\/\/www.ietf.org\/rfc\/rfc1321.txt."},{"key":"ref_46","unstructured":"Eastlake, D., and Jones, P. (2025, October 28). US Secure Hash Algorithm 1 (SHA1). IETF RFC3174. Available online: https:\/\/www.rfc-editor.org\/rfc\/rfc3174.html."},{"key":"ref_47","unstructured":"(1995). Secure Hash Standard (Standard No. FIPS 180-1)."},{"key":"ref_48","unstructured":"Klima, V. (2025, October 28). Finding MD5 Collisions\u2013a Toy For a Notebook. Cryptol. Eprint Arch. Available online: https:\/\/eprint.iacr.org\/2005\/075.pdf."},{"key":"ref_49","unstructured":"Wang, X., Yin, Y., and Yu, H. (2005, January 14\u201318). Finding Collisions in the Full SHA-1. Proceedings of the 25th Annual International Cryptology Conference, Santa Barbara, CA, USA."},{"key":"ref_50","doi-asserted-by":"crossref","unstructured":"Black, J., Cochran, M., and Highland, T. (2006, January 15\u201317). A Study of the MD5 Attacks: Insights and Improvements. Proceedings of the 13th International Workshop, Fast Software Encryption, Graz, Austria.","DOI":"10.1007\/11799313_17"},{"key":"ref_51","unstructured":"National Institute of Standards and Technology (2025, October 28). NIST Transitioning Away from SHA-1 for All Applications, Available online: https:\/\/www.nist.gov\/news-events\/news\/2022\/12\/nist-transitioning-away-sha-1-all-applications."},{"key":"ref_52","unstructured":"(2015). Secure Hash Standard (SHS) (Standard No. FIPS PUB 180-4)."},{"key":"ref_53","unstructured":"(2015). SHA-3 Standard: Permutation-Based Hash and Extendable-Output Functions (Standard No. FIPS PUB 202)."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"36","DOI":"10.1145\/3589641","article-title":"A Vulnerability Assessment Framework for Privacy-preserving Record Linkage","volume":"26","author":"Vidanage","year":"2023","journal-title":"ACM Trans. Priv. Secur."},{"key":"ref_55","unstructured":"(2025, October 28). GDPR, GDPR, REGULATION (EU) 2016\/679 of the European Parliament and of the Council of 27 April 2016 on the Protection of Natural Persons with Regard to the Processing of Personal Data and on the Free Movement of Such Data. Available online: https:\/\/eur-lex.europa.eu\/eli\/reg\/2016\/679\/oj\/eng."},{"key":"ref_56","unstructured":"EDPB (2025, October 28). Guidelines 01\/2025 on Pseudonymization. Available online: https:\/\/www.edpb.europa.eu\/our-work-tools\/documents\/public-consultations\/2025\/guidelines-012025-pseudonymisation_en."},{"key":"ref_57","unstructured":"ENISA (2025, October 28). Data Pseudonymisation: Advanced Techniques & Use Cases. Available online: https:\/\/www.enisa.europa.eu\/publications\/data-pseudonymisation-advanced-techniques-and-use-cases."},{"key":"ref_58","first-page":"34","article-title":"Fighting Crime Online","volume":"68","author":"Danaher","year":"2025","journal-title":"Assoc. Comput. Mach."},{"key":"ref_59","unstructured":"ENISA (2025, October 28). Recommendations on Shaping Technology According to GDPR Provisions: An Overview on Data Pseudonymization. Available online: https:\/\/www.enisa.europa.eu\/publications\/recommendations-on-shaping-technology-according-to-gdpr-provisions."},{"key":"ref_60","unstructured":"Microsoft Research, and Farid, H. (2025, October 28). PhotoDNA. Available online: https:\/\/www.microsoft.com\/en-us\/photodna."},{"key":"ref_61","unstructured":"Impact Assessment Report (2025, October 28). Commission Staff Working Document Impact Assessment Report Accompanying the document Proposal for a Regulation of the European Parliament and of the Council laying down rules to prevent and combat child sexual abuse. Available online: https:\/\/eur-lex.europa.eu\/legal-content\/EN\/TXT\/?uri=celex:52022SC0209."},{"key":"ref_62","unstructured":"EPRS (2025, October 28). Complementary Impact Assessment Report. Available online: https:\/\/www.ecorys.com\/app\/uploads\/files\/2023-05\/EPRS_STU(2023)740248_EN.pdf."},{"key":"ref_63","unstructured":"Athalye, A. (2025, October 28). Inverting PhotoDNA: Reconstructing Images from Hashes. Personal blog and GitHub. Available online: https:\/\/anishathalye.com\/inverting-photodna."},{"key":"ref_64","unstructured":"Madden, J., Bhavsar, M., Dorje, L., and Li, X. (2024). Robustness of Practical Perceptual Hashing Algorithms to Hash-Evasion and Hash-Inversion Attacks. NeurIPS 2024 Workshop on New Frontiers in Adversarial Machine Learning. arXiv."},{"key":"ref_65","unstructured":"Prokos, J., Fendley, N., Green, M., Schuster, R., Tromer, E., Jois, T., and Cao, Y. (2023, January 9\u201311). Squint Hard Enough: Attacking Perceptual Hashing with Adversarial Machine Learning. Proceedings of the 32nd USENIX Security Symposium (USENIX Security 23), Anaheim, CA, USA."},{"key":"ref_66","doi-asserted-by":"crossref","first-page":"64","DOI":"10.1109\/MSEC.2024.3485497","article-title":"Perceptual Hash Inversion Attacks on Image-Based Sexual Abuse Removal Tools","volume":"23","author":"Hawkes","year":"2025","journal-title":"IEEE Secur. Priv."},{"key":"ref_67","unstructured":"INTERPOL (2025, October 28). INTERPOL\u2019s Child Sexual Exploitation Database. INTERPOL and ECPAT. Available online: https:\/\/www.interpol.int\/en\/content\/download\/9363\/file\/Summary%20-%20Towards%20a%20Global%20Indicator%20on%20Unidentified%20Victims%20in%20Child%20Sexual%20Exploitation%20Material.%20February%202018.pdf."},{"key":"ref_68","doi-asserted-by":"crossref","first-page":"105440","DOI":"10.1016\/j.clsr.2020.105440","article-title":"Investigating the dynamics of illegal online activity: The power of reporting, dark web, and related legislation","volume":"38","author":"Kokolaki","year":"2020","journal-title":"Comput. Law Secur. Rev."},{"key":"ref_69","unstructured":"Google\/YouTube (2025, October 28). CSAI Match: Video Fingerprinting System for Known CSAM Detection. Available online: https:\/\/protectingchildren.google\/tools-for-partners."},{"key":"ref_70","unstructured":"Gupta, D. (2025, October 28). Apple Renounces NeuralHash, Its Controversial Anti-CSAM System. \u03a4echunwrapped. Available online: https:\/\/techunwrapped.com\/apple-renounces-neuralhash-its-controversial-anti-csam-system."},{"key":"ref_71","unstructured":"Internet Watch Foundation (2025, October 28). IWF Hash List: A Database of Hashes of Known Child Sexual Abuse Material. Available online: https:\/\/www.iwf.org.uk\/our-technology\/our-services\/image-hash-list."},{"key":"ref_72","unstructured":"National Center for Missing & Exploited Children (2025, October 28). NCMEC CSAM Hash Database and CyberTipline System. Available online: https:\/\/www.missingkids.org\/gethelpnow\/cybertipline."},{"key":"ref_73","unstructured":"Thorn (2025, October 28). Introducing Safer Match, API-Based CSAM Detection. Thorn., Available online: https:\/\/www.thorn.org\/blog\/safer-match."},{"key":"ref_74","unstructured":"Canadian Centre for Child Protection (2025, October 28). Project Arachnid: Reducing the Online Availability of Child Sexual Abuse Material. Available online: https:\/\/www.projectarachnid.ca."},{"key":"ref_75","unstructured":"Web-IQ, B.V. (2025, October 28). Hash Check Server (HCS): Scalable CSAM Hash Matching Service. Available online: https:\/\/www.web-iq.com."},{"key":"ref_76","unstructured":"World Childhood Foundation (2025, October 28). Advancing Technology to Stop Child Sexual Abuse, World Childhood Foundation. Available online: https:\/\/childhood.org\/news\/advancing-technology-to-stop-child-sexual-abuse\/."},{"key":"ref_77","unstructured":"Jain, S., Cre\u021bu, A.-M., and de Montjoye, Y.-A. (2022, January 10\u201312). Adversarial Detection Avoidance Attacks: Evaluating the robustness of perceptual hashing-based client-side scanning. Proceedings of the 31st USENIX Security Symposium, Boston, MA, USA."},{"key":"ref_78","unstructured":"INHOPE (2025, October 28). e-Privacy Derogation Passes & New Regulations. Available online: https:\/\/inhope.org\/EN\/articles\/e-privacy-derogation-passes-new-regulations."},{"key":"ref_79","unstructured":"e-Privacy (2025, October 28). Directive 2002\/58\/EC of the European Parliament and of the Council of 12 July 2002 Concerning the Processing of Personal Data and the Protection of Privacy in the Electronic Communications Sector (Directive on Privacy and Electronic Communications). Available online: https:\/\/eur-lex.europa.eu\/eli\/dir\/2002\/58\/oj\/eng."},{"key":"ref_80","unstructured":"Interim Regulation (2025, October 28). Regulation (EU) 2021\/1232 of the European Parliament and of the Council of 14 July 2021 on a Temporary Derogation from Certain Provisions of Directive 2002\/58\/Ec as Regards the Use of Technologies by Providers of Number-Independent Interpersonal Communications. Available online: https:\/\/eur-lex.europa.eu\/legal-content\/EN\/TXT\/?uri=uriserv:OJ.L_.2021.274.01.0041.01.ENG."},{"key":"ref_81","unstructured":"Interim Regulation Amendment (2025, October 28). Regulation (EU) 2024\/1307 of the European Parliament and of the Council of 29 April 2024 Amending Regulation (EU) 2021\/1232 on a Temporary Derogation from Certain Provisions of Directive 2002\/58\/Ec as Regards the Use of Technologies by Providers of Number. Available online: https:\/\/eur-lex.europa.eu\/legal-content\/EN\/TXT\/?uri=CELEX%3A32024R1307."},{"key":"ref_82","unstructured":"CSAR (2025, October 28). Proposal for a Regulation of the European and of the Council Laying Down Rules to Prevent and Combat Child Sexual Abuse. Available online: https:\/\/eur-lex.europa.eu\/legal-content\/EN\/TXT\/?uri=COM%3A2022%3A209%3AFIN&qid=1652451192472."},{"key":"ref_83","unstructured":"EDRi (2025, October 28). CSA Regulation Document Pool. Available online: https:\/\/edri.org\/our-work\/csa-regulation-document-pool\/?utm_source=chatgpt.com#council."},{"key":"ref_84","doi-asserted-by":"crossref","first-page":"106097","DOI":"10.1016\/j.clsr.2024.106097","article-title":"Preventing the dissemination of child sexual abuse material (CSAM) with surveillance technologies: The case of EU Regulation 2021\/1232","volume":"56","author":"Rojszczak","year":"2025","journal-title":"Comput. Law Secur. Rev."},{"key":"ref_85","unstructured":"EDPS, and EDPB (2025, October 28). Joint Opinion 04\/2022 on the Proposal for a Regulation of the European Parliament and of the Council Laying Down Rules to Prevent and Combat Child Sexual Abuse. Available online: https:\/\/www.edpb.europa.eu\/system\/files\/2022-07\/edpb_edps_jointopinion_202204_csam_en_0.pdf."}],"container-title":["Journal of Cybersecurity and Privacy"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2624-800X\/5\/4\/92\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,11,6]],"date-time":"2025-11-06T05:12:42Z","timestamp":1762405962000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2624-800X\/5\/4\/92"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,10,31]]},"references-count":85,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2025,12]]}},"alternative-id":["jcp5040092"],"URL":"https:\/\/doi.org\/10.3390\/jcp5040092","relation":{},"ISSN":["2624-800X"],"issn-type":[{"type":"electronic","value":"2624-800X"}],"subject":[],"published":{"date-parts":[[2025,10,31]]}}}