The way hashcash poses a challenge is by asking "minters" to produce strings (stamps) that when hashed with the Secure Hash Algorithm, SHA-1, have a number of leading zeros in their hash.

hashcash 提出质询的方式是，当通过安全散列算法（Secure Hash Algorithm）进行散列时，要求“minters”生成 一个字符串（戳记，stamps），在它们的散列中有很多前导零。

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A mask used to retrieve a revision of the Secure Hash Algorithm that corrects an unpublished flaw in SHA.

用于检索“安全哈希算法”修订版的掩码，该修订版更正了SHA中的一个未发布的错误。

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