Shorter version of md5 using JavaScript..?

Question

I have an array of objects in a JSON file. The objects don't have unique ids so I need to create either a unique id, or a unique string.

[
  {
    "name": "Jack Potts",
    "age": "56"
  }, {
    "name": "Rusty Carr",
    "age": "31"
  }
]

I know I can use MD5, passing in the object, but I'm going to use the string in a URL, so I'd prefer it to be shorter.

Rather than /people/3449c9e5e332f1dbb81505cd739fbf3f, I'd prefer something more like /people/1dbb81505.

It still needs to be a representation of the object because I'm going to lookup the person again from the URL.

Is there anything that produces a string shorter than the MD5 string..?

I'm going to guess that MD5 is my best/only option, but I thought I'd ask.

UPDATE

I maybe wasn't as clear as I could have been. I don't just need to generate a unique id. I won't be updating the JSON file with whatever I generate.

I need a way to take the object in question, create a URL for it, then when the URL is visited use the URL to get back to that object in the array.

As far as I know, if you pass in the same string to MD5 over and over, it will always return the same MD5 string because it's a representation. Don't people use this when storing passwords in a database for the same reason?

Maybe MD5 is fine, I just thought there might be something which produced a shorter string which is a representation of the data. That's my question.

UPDATE 2

The people in the array may change. People may be added and removed so using the array index won't work.

Answer 1

If you just want a shorter output that MD5 but are otherwise satisfied with the uniqueness just truncate to the length you need, each bit is as random as any other bit, that is any subset of the bits you choose are just as good as any other subset.

But realize that if two names are the same you will get the same hash.

As you must realize the shorter the hash the higher change of a collision, you are making a tradeoff of hash length vs uniqueness, that is not bad, just be sure you have enough uniqueness for your needs.