turns a base64 encoded string into a byte array

(-> (from-base64 “aGVsbG8=”) (String.)) => “hello”

turns a hex string into a sequence of bytes

(String. (from-hex “68656c6c6f”)) => “hello”

turns two hex characters into a byte value

(byte (from-hex-chars  \a)) => 42

turns a byte into two chars

(hex-chars 255) => \f \f

(hex-chars 42) =>  \a

turns a byte array into a base64 encoded string

(-> (.getBytes “hello”) (to-base64)) => “aGVsbG8=”

turns a byte array into a base64 encoding

(-> (.getBytes “hello”) (to-base64-bytes) (String.)) => “aGVsbG8=”

turns a byte array into hex string

(to-hex (.getBytes “hello”)) => “68656c6c6f”

turns a byte array into a hex char array