| gptkbp:instanceOf | gptkb:proof-of-work_system 
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                                | gptkbp:category | gptkb:anti-spam_technology computer security
 cryptography
 
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                                | gptkbp:citation | gptkb:Back,_Adam._'Hashcash_-_A_Denial_of_Service_Counter-Measure.'_2002. 
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                                | gptkbp:hashFunction | gptkb:SHA-1 
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                                | gptkbp:influenced | gptkb:Bitcoin cryptocurrencies
 
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                                | gptkbp:introducedIn | 1997 
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                                | gptkbp:inventedBy | gptkb:Adam_Back 
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                                | gptkbp:license | gptkb:MIT_License 
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                                | gptkbp:mechanismOfAction | requires computational work to generate a stamp 
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                                | gptkbp:notableFor | email anti-spam Bitcoin mining
 
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                                | gptkbp:openSource | true 
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                                | gptkbp:purpose | mitigate email spam prevent denial-of-service attacks
 
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                                | gptkbp:relatedConcept | gptkb:hash_function gptkb:Bitcoin
 gptkb:proof-of-work
 email spam filtering
 
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                                | gptkbp:stampFormat | version:bits:date:resource:ext:rand:counter 
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                                | gptkbp:supportsAlgorithm | gptkb:hash_function 
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                                | gptkbp:website | https://www.hashcash.org/ 
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                                | gptkbp:bfsParent | gptkb:Proof-of-Work gptkb:Proof_of_Work
 gptkb:Adam_Back
 
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                                | gptkbp:bfsLayer | 6 
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                                | https://www.w3.org/2000/01/rdf-schema#label | Hashcash 
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