What is the purpose of the Hash Blocklist (HBL)?
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What is the purpose of the Hash Blocklist (HBL)?
What is the purpose of the Hash Blocklist (HBL)?
The blocklist contains the following content areas: cryptowallet (Bitcoin etc.), malware, email addresses and URLs (including shorteners, redirectors and online file storage providers). Identifying such elements in spam messages and then publishing them in the Hash Blocklist (HBL) provides another means for administrators to filter their inbound email.
- Mail server software is expected to be able to identify and extract these message elements, compute their cryptographic hashes, and compare them to HBL data.
- Hash functions are a widely used industry standard that serve two purposes in HBL:
- It reduces the size of the represented data to a unique, fixed-size string;
- The hashes cannot be reverted to the original content. That precludes the disclosure of the content in distributed data which may be disallowed by specific privacy laws.