github.com/dchest/uniuri (go): Package uniuri generates random strings good for use in URIs to identify unique objects.  Example usage:  A standard string created by New() is 16 bytes in length and consists of Latin upper and lowercase letters, and numbers (from the set of 62 allowed characters), which means that it has ~95 bits of entropy. To get more entropy, you can use NewLen(UUIDLen), which returns 20-byte string, giving ~119 bits of entropy, or any other desired length.  Functions read from crypto/rand random source, and panic if they fail to read from it.
Keywords: golang|random|random-string|secure|uuid