The DOI matches its Crossref record; 7 of the 7 references it cites were found in a registry or an index.
CAPTCHA: Using Hard AI Problems for Security
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Citations
Cites
Telling humans and computers apart automatically
von Ahn, L., Blum, M., & Langford, J. (2004) · Communications of the ACM · doi:10.1145/966389.966390 · Cited by 895
Self-citationSecuring passwords against dictionary attacks
Pinkas, B., & Sander, T. (2002) · Proceedings of the 9th ACM conference on Computer and communications security · doi:10.1145/586110.586133 · Cited by 307
Hopper, N. J., Langford, J., & von Ahn, L. (2002) · Lecture Notes in Computer Science · doi:10.1007/3-540-45708-9_6 · Cited by 198
Self-citationPessimalPrint: a reverse Turing test
Baird, H. S., Coates, A. L., & Fateman, R. J. (2003) · International Journal on Document Analysis and Recognition · doi:10.1007/s10032-002-0089-1 · Cited by 159
On Public-Key Steganography in the Presence of an Active Warden
Craver, S. A. (1998) · Lecture notes in computer science · doi:10.1007/3-540-49380-8_25 · Cited by 128
Optical character recognition: an illustrated guide to the frontier
Nagy, G., Nartker, T. A., & Rice, S. V. (1999) · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · doi:10.1117/12.373511 · Cited by 118
Pessimal print: a reverse Turing test
Coates, A., Baird, H. S., & Faternan, R. J. (2002) · Proceedings of the International Conference on Document Analysis and Recognition · doi:10.1109/icdar.2001.953966 · Cited by 88
Cited by
Fake It Till You Make It: Reputation, Competition, and Yelp Review Fraud
Luca, M., & Zervas, G. (2016) · Management Science · doi:10.1287/mnsc.2015.2304 · Cited by 1,263
reCAPTCHA: Human-Based Character Recognition via Web Security Measures
von Ahn, L., Maurer, B., McMillen, C., Abraham, D., & Blum, M. (2008) · Science · doi:10.1126/science.1160379 · Cited by 1,115
Self-citationThe spread of low-credibility content by social bots
Shao, C., Ciampaglia, G. L., Varol, O., Yang, K.-C., Flammini, A., & Menczer, F. (2018) · Nature Communications · doi:10.1038/s41467-018-06930-7 · Cited by 1,125
Dziembowski, S., Faust, S., Kolmogorov, V., & Pietrzak, K. (2015) · Lecture Notes in Computer Science · doi:10.1007/978-3-662-48000-7_29 · Cited by 294
Sybillimit: a near-optimal social network defense against sybil attacks
Yu, H., Gibbons, P. B., Kaminsky, M., & Xiao, F. (2010) · IEEE/ACM Transactions on Networking · doi:10.1109/tnet.2009.2034047 · Cited by 246
Metadata
- Authors
- von Ahn, L., Blum, M., Hopper, N. J., & Langford, J.
- Venue
- Lecture Notes in Computer Science
- Publisher
- Springer Berlin Heidelberg
- Published
- 2003
- Pages
- 294-311
- ISSN
- 0302-9743 (ISSN-L)
- OpenAlex
- W1603565383
- Cited by
- 1,447
- References
- 7
- FWCI
- 26.08
- Type
- conference paper
- Language
- en
- Open access
- bronze
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Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
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- CoChat. (2026). Citation check: CAPTCHA: Using Hard AI Problems for Security. https://app.cochat.ai/papers/10.1007/3-540-39200-9_18
- The paper
- von Ahn, L., Blum, M., Hopper, N. J., & Langford, J. (2003). CAPTCHA: Using Hard AI Problems for Security. Lecture Notes in Computer Science. https://doi.org/10.1007/3-540-39200-9_18
Data sources
Bibliographic data: Semantic Scholar, OpenAlex, Crossref.
Contains information from the Semantic Scholar Academic Graph Datasets, made available under the ODC Attribution License (ODC-BY 1.0).
Semantic Scholar’s data is described in: Kinney, R., et al. (2023). The Semantic Scholar Open Data Platform. arXiv:2301.10140.
