Is there some ready-made algorithm to generate invitation code by ruby

Is there some ready-made algorithm to generate invitation code by ruby? I can think at first MD5, 开发者_StackOverflow社区but its output is too long for 32, so I want the output length is less than 16.

Thank you in advance.

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Assuming you are storing the code (otherwise, what's the point?) just make a random string, and check to see if it exists before saving, and try a new string if it does. No major algorithm needed.

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How "secure" do you want your invitation code? You could generate an MD5 hash and simply take the first or last 16 characters, or any 16-character combination from the hash code (e.g. every other position in the hash). That should be good enough for an invitation-code.

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SecureRandom.uuid

This will produce out put like the following.

2.1.0 :005 > SecureRandom.uuid
 => "b2a8ed4c-f71f-4c7d-a0fb-a66de58d37cc" 
2.1.0 :006 > 

Short enough and extremely unlikely to cause a collision.