## 2 State of the Art
### Verification of Deep Audio Fakes: A Challenge for Journalism  
As previously described in the Introduction Section, concern about deepfakes has increased significantly, boosting the relevance of the journalistic work of verifying information and news. In Spain, organizations such as Verifica RTVE, the EFE Verifica agency, Maldita.es, and Newtral play a crucial role in this context, constantly working to identify and expose false or manipulated content [27]. Internationally, we can also find institutions such as the International Fact-Checking Network (IFCN) who have been pioneers in this field, providing resources and standards that help newsrooms maintain the accuracy of information. These groups specialize in analyzing and verifying information, offering an essential service to maintain the integrity of public discourse and trust in the media. Internationally, several verification organizations offer tools and resources to combat disinformation and fake news. For example, the Duke Reporters' Lab ([[https://reporterslab.org/](https://reporterslab.org/)]([https://reporterslab.org/](https://reporterslab.org/)), accessed on 23 October 2024), a journalism research center at Duke University's Sanford School of Public Policy, offers tools such as ClaimReview for tagging articles on social media and search engines, and MediaReview, Squash, and FactStream for data verification of images, videos, and speeches, respectively. Additionally, this laboratory has established important collaborations with other large fact checkers such as PolitiFact [28] and FactCheck.org, creating a robust verification ecosystem. Likewise, the International Fact-Checking Network (IFCN), created by the Poynter Institute in 2015, promotes good journalistic practices regarding disinformation and verification of information. Organizations such as these establish codes of principles that all members must follow, thus ensuring a consistent and transparent methodology in fact-checking. This network also facilitates collaboration between its members, allowing for the exchange of advanced technologies and methodologies in the detection of disinformation. In Spain, initiatives such as Verifica RTVE and EFE Verifica stand out in the fight against misinformation and fake news. EFE Verifica is dedicated to verifying the information that circulates on the Internet and social networks [29]. On the other hand, Verifica RTVE not only focuses on news verification, but is also actively involved in educating the public on how to identify fake news and better understand media in the digital age [30; 31]. For example, Verifica RTVE has an openly accessible website in which they specify all the tools that can be used to verify all types of content ([[https://www.rtve.es/noticias/verificartve/](https://www.rtve.es/noticias/verificartve/)]([https://www.rtve.es/noticias/verificartve/](https://www.rtve.es/noticias/verificartve/)), accessed on 23 October 2024). Traditionally, the focus has been almost exclusively on video and image deepfakes, with less emphasis on audio due to its, until recently, more modest presence in news-rooms [32]. However, with the growing appearance of fake audio, newsrooms are incorporating technological tools to help journalists detect these fakes. Tools such as the voice classifier from ElevenLabs, AI or Not, Voice Classifier from Play.ht, VerificAudio from PRISA media, and Resemble Detect from ResembleAI are examples of how technology is supporting journalistic work. These systems analyze the characteristics of voice recordings and determine whether they have been generated by AI, providing additional verification opinion that journalists can use to confirm the authenticity of the audio received. Nevertheless, these tools can only be considered a complement to journalistic work: as no tool has a zero error rate, it is still necessary to understand the context in which deepfakes are generated in order to decide on the veracity of the information content.