SHA-256 in clojure

sha256.clj

(defn sha256 [string]
  (let [digest (.digest (MessageDigest/getInstance "SHA-256") (.getBytes string "UTF-8"))]
    (apply str (map (partial format "%02x") digest))))

This is wrong.

Works like a charm.

This is wrong. It gets the padding wrong when converting the bytes into a hex string, and so will be correct for bytes with values 16-255 and wrong if any of the generated values are 15 or below. Do this instead:

(defn sha256 [string]
  (let [digest (.digest (MessageDigest/getInstance "SHA-256") (.getBytes string "UTF-8"))]
    (apply str (map (partial format "%02x") digest))))

@l0st3d OK, now it's clear. Thanks for sharing this!

@l0st3d thanks - I will update the gist according to your solution

This will use reflection for the .getBytes call. In clojure 1.12 you can change that to String/.getBytes to avoid this.

(Can also type hint of course, but I personally like this syntax better.)