~ hash

src/b32.ml

@@ -29,6 +29,10 @@ let decode s =
         | c -> c)
       s
   in
+  (* restore padding for base32 lib *)
+  let n = 8 - (String.length s mod 8) in
+  let pad = String.make n '=' in
+  let s = s ^ pad in
   match Base32.decode ~alphabet ~off:0 ~len:(String.length s) s with
   | Error (`Msg e) -> Error e
   | Ok v -> Ok v

src/hash.ml

@@ -1,3 +1,4 @@
+(* TODO use SHA512.of_raw_string_opt *)
 open Digestif
 
 module type S = sig
@@ -18,9 +19,9 @@ module H32 = struct
   let hash s = SHA256.(digest_string s)
 
   let of_octets s =
-    match String.length s = 32 with
-    | false -> Fmt.failwith "Hash.of_octets failure: data is not 32 bytes"
-    | true -> SHA256.of_raw_string s
+    match SHA256.of_raw_string_opt s with
+    | None -> Fmt.failwith "H32.of_octets failure: data is not 32 bytes"
+    | Some t -> t
 
   let to_octets = SHA256.to_raw_string
   let of_b32 s = Result.map of_octets (B32.decode s)
@@ -48,16 +49,11 @@ module H64 = struct
   let hash s = SHA512.(digest_string s)
 
   let of_octets s =
-    match String.length s = 64 with
-    | false -> Fmt.failwith "Hash.of_octets failure: data is not 64 bytes"
-    | true -> SHA512.of_raw_string s
-
-  let to_octets v =
-    let s = SHA512.to_raw_string v in
-    match String.length s = 64 with
-    | false -> Fmt.failwith "Hash.to_octets failure: data is not 64 bytes"
-    | true -> s
+    match SHA512.of_raw_string_opt s with
+    | None -> Fmt.failwith "H64.of_octets failure: data is not 64 bytes"
+    | Some t -> t
 
+  let to_octets = SHA512.to_raw_string
   let of_b32 s = Result.map of_octets (B32.decode s)
 
   let bin =

test/b32.ml

@@ -1,15 +1,28 @@
-let () =
-  let id s = s |> B32.encode |> B32.decode |> Result.get_ok in
-  let f s =
-    let s' = id s in
+let round_trip s =
+  let s' = s |> B32.encode |> B32.decode |> Result.get_ok in
   match s' = s with
-    | false ->
-        Fmt.failwith "b32 round trip failure: @\nin :`%S`@\nout:`%S`" s' s
+  | false -> Fmt.failwith "b32 round trip failure: @\nin :`%S`@\nout:`%S`" s' s
   | true -> ()
-  in
+
+let () =
   let s = String.init 0xff Char.chr in
+  round_trip s;
   let s_l = List.init 0x0f (fun i -> String.init i Char.chr) in
-  f s;
-  List.iter f s_l;
+  List.iter round_trip s_l; ()
+
+let () =
+  let input = "91JPRV3F5GG4EKJNDSJQ8" in
+  let output =
+    input
+    |> B32.decode
+    |> Result.get_ok
+    |> Hash.H64.hash
+    |> Hash.H64.to_octets
+    |> B32.encode
+  in
+  let expected =
+    "D0R24RZ1TPASVQ2NY56CT8AJDYZE9ZGDB0GVZ05E9D4YGZQW2RC5YFPQ0Q86EPW836DY7VYQTNFFJT3ZR2K508F4JVS5JNJKYN2MMFR"
+  in
+  assert (output = expected);
 
   ()

test/dune

@@ -6,7 +6,7 @@
 (test
  (name b32)
  (modules b32)
- (libraries b32 fmt))
+ (libraries mte b32 fmt))
 
 ; TODO
 ; cram test?