Cryptographically secure 32-bit RNG in strict ZSH

srandom() { zmodload zsh/system; local byte; local -i rnd=0; repeat 4; do sysread -s 1 byte || return; rnd=$(( rnd << 8 | #byte )); done < /dev/urandom; print -r -- $rnd; }
ZSH ships a couple random number generators via the $RANDOM environment variable and rand48() via zsh/mathfunc, but neither are cryptographically secure. This code produces a 32-bit random number suitable for cryptography. It's only dependency is /dev/urandom and it does not rely on any shell commands or 3rd party utilities. It assumes ZSH was compiled with 64-bit integer support.
Sample Output 
1018359216

1
By: atoponce
2020-12-17 13:39:17
random zsh cryptography
3
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