msg7086 · October 3, 2016 15:07
diff --git a/v2ex-309785.rb b/v2ex-309785.rb
 require 'digest' 

 md5 = '3bed22f7f496e84b035a996522baa7594c27c7e5718a78bfddf9012904b70eb755d67f90c8de149ead7ee674b024f38c216642030c2d54cb1dd657dd66342c99c239f3c31fd399fc052a9b7861f2073d2b9f47811dd77fd544d570c34bf5f349d110389979571714694a5054238465ca38ba26c25fb1a32b4d0a3b93666b09b3' 
 prefix = Digest::MD5.hexdigest 'v2ex' 
 str = '' 

 md5.scan(/.{32}/) { |m| str += [*'0'..'9',*'A'..'Z',*'a'..'z'].find { |s| Digest::MD5.hexdigest(prefix + str + s + Digest::MD5.hexdigest(str + s)) == m } } 

 puts str #=> csdaixie
	require 'digest'

	md5 = '3bed22f7f496e84b035a996522baa7594c27c7e5718a78bfddf9012904b70eb755d67f90c8de149ead7ee674b024f38c216642030c2d54cb1dd657dd66342c99c239f3c31fd399fc052a9b7861f2073d2b9f47811dd77fd544d570c34bf5f349d110389979571714694a5054238465ca38ba26c25fb1a32b4d0a3b93666b09b3'
	prefix = Digest::MD5.hexdigest 'v2ex'
	str = ''

	md5.scan(/.{32}/) { \|m\| str += ['0'..'9','A'..'Z',*'a'..'z'].find { \|s\| Digest::MD5.hexdigest(prefix + str + s + Digest::MD5.hexdigest(str + s)) == m } }

	puts str #=> csdaixie