openssl vs digestif

bench.ml

external openssl_sha1 : string -> string = "camlopenssl_sha1"

external openssl_blake2b : string -> string = "camlopenssl_blake2b"

let bench_sha1 () =
  let input_len = 100_000 in
  let input = String.make input_len ' ' in
  let run_digestif () = Digestif.SHA1.digest_string input in
  let run_openssl () = openssl_sha1 input |> Digestif.SHA1.of_raw_string in
  Benchmark.throughputN 1
    [ ("digestif", run_digestif, ()); ("openssl", run_openssl, ()) ]

let bench_blake2b () =
  let input_len = 100_000 in
  let input = String.make input_len ' ' in
  let run_digestif () = Digestif.BLAKE2B.digest_string input in
  let run_openssl () =
    openssl_blake2b input |> Digestif.BLAKE2B.of_raw_string
  in
  Benchmark.throughputN 1
    [ ("digestif", run_digestif, ()); ("openssl", run_openssl, ()) ]

let () =
  let open Benchmark.Tree in
  register @@ "Digest"
  @>>> [ "sha1" @> lazy (bench_sha1 ()); "blake2b" @> lazy (bench_blake2b ()) ]

let () = Benchmark.Tree.run_global ()

dune

(executable
 (name bench)
 (libraries benchmark digestif)
 (foreign_stubs
  (language c)
  (names stubs))
 (link_flags :standard -cclib -lcrypto))

(rule
 (alias runtest)
 (action
  (run ./bench.exe --all)))

stubs.c

#include <caml/memory.h>
#include <caml/alloc.h>
#include <openssl/sha.h>
#include <openssl/evp.h>

value camlopenssl_sha1 (value v_input)
{
	CAMLparam1(v_input);
	const char* input = String_val(v_input);
	int len = caml_string_length(v_input);
	CAMLlocal1(v_output);
	v_output = caml_alloc_string(SHA_DIGEST_LENGTH);
	char* output = Bytes_val(v_output);
	SHA1(input, len, output);
	CAMLreturn(v_output);
}

value camlopenssl_blake2b (value v_input)
{
	CAMLparam1(v_input);
	const char* input = String_val(v_input);
	int len = caml_string_length(v_input);
	CAMLlocal1(v_output);
	const EVP_MD *md = EVP_blake2b512();
	int output_size = EVP_MD_size(md);
	v_output = caml_alloc_string(output_size);
	char* output = Bytes_val(v_output);
	EVP_Digest(input, len, output, &output_size, md, NULL);
	CAMLreturn(v_output);
}