module Spaceship::Hashcash
Public Class Methods
Source
# File spaceship/lib/spaceship/hashcash.rb, line 35 def self.make(bits:, challenge:) version = 1 date = Time.now.strftime("%Y%m%d%H%M%S") counter = 0 loop do hc = [ version, bits, date, challenge, ":#{counter}" ].join(":") if Digest::SHA1.digest(hc).unpack1('B*')[0, bits.to_i].to_i == 0 return hc end counter += 1 end end
This App
Store Connect hashcash spec was generously donated by…
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<summary>
1:11:20230223170600:4d74fb15eb23f465f1f6fcbf534e5877::6373
X-APPLE-HC: 1:11:20230223170600:4d74fb15eb23f465f1f6fcbf534e5877::6373
^ ^ ^ ^ ^ | | | | +-- Counter | | | +-- Resource | | +-- Date YYMMDD[hhmm[ss]] | +-- Bits (number of leading zeros) +-- Version
We can’t use an off-the-shelf Hashcash
because Apple’s implementation is not quite the same as the spec/convention.
1. The spec calls for a nonce called "Rand" to be inserted between the Ext and Counter. They don't do that at all. 2. The Counter conventionally encoded as base-64 but Apple just uses the decimal number's string representation.
Iterate from Counter=0 to Counter=N finding an N that makes the SHA1(X-APPLE-HC) lead with Bits leading zero bits
We get the “Resource” from the X-Apple-HC-Challenge header and Bits from X-Apple-HC-Bits
</summary>