My limited understanding of md5 is that the result will be 128 bits, and 128 / 8 = 16 bytes, which is the same as CC_MD5_DIGEST_LENGTH from CommonCrypto. However, when I use Insecure.MD5 from CryptoKit, the digest has 20 bytes with zeros at the end!
I'm not sure if Insecure.MD5Digest.byteCount is intended to be 20, or is this by mistake?