src/binary_formats.ml

@@ -85,12 +85,12 @@ module UTIL = struct
   module MK_HASH_32 () : sig
     type t = private { hash: string }
 
-    val of_string : string -> t
+    val of_octets : string -> t
     val bin : t Bin.t
   end = struct
     type t = { hash: string }
 
-    let of_string s =
+    let of_octets s =
       match String.length s = 32 with
       | false -> Fmt.failwith "SHA256 failure: data is not 32 bytes"
       | true ->
@@ -125,6 +125,58 @@ module UTIL = struct
       |+ field (bytes 64) (fun t -> t.hash)
       |> sealr
   end
+
+  module HASH_32_WITH_NULL : sig
+    type t
+
+    val hash_with_null : string -> t
+    val bin : t Bin.t
+  end = struct
+    type t = { hash: string }
+
+    let hash_with_null s =
+      let s =
+        let len = String.length s in
+        let b = Bytes.create (len + 1) in
+        Bytes.blit_string s 0 b 0 len;
+        Bytes.set b len '\x00';
+        Bytes.unsafe_to_string b
+      in
+      let hash = Digestif.SHA256.(to_raw_string (digest_string s)) in
+      { hash }
+
+    let bin =
+      let open Bin in
+      record (fun hash -> { hash })
+      |+ field (bytes 32) (fun t -> t.hash)
+      |> sealr
+  end
+
+  module HASH_64_WITH_NULL : sig
+    type t
+
+    val hash_with_null : string -> t
+    val bin : t Bin.t
+  end = struct
+    type t = { hash: string }
+
+    let hash_with_null s =
+      let s =
+        let len = String.length s in
+        let b = Bytes.create (len + 1) in
+        Bytes.blit_string s 0 b 0 len;
+        Bytes.set b len '\x00';
+        Bytes.unsafe_to_string b
+      in
+      let hash = Digestif.SHA512.(to_raw_string (digest_string s)) in
+      { hash }
+
+    let bin =
+      let open Bin in
+      record (fun hash -> { hash })
+      |+ field (bytes 64) (fun t -> t.hash)
+      |> sealr
+  end
 end
 
 open UTIL
@@ -141,6 +193,76 @@ module TimestampNBO = MK_TIME_NBO ()
 
 (* -- Cryptographic primitives -- *)
 
+(* GNUNET_CRYPTO format *)
+module GNUNET_RsaPublicKey = struct
+  (* libgnuutil format:
+     https://docs.gnunet.org/doxygen/d9/dbe/structGNUNET__CRYPTO__RsaPublicKeyHeaderP.html
+     https://docs.gnunet.org/doxygen/d6/d70/group__libgnunetutil.html#ga9c99a81e8cd649c1c925d23211a0738f
+     https://www.gnupg.org/documentation/manuals/gcrypt/MPI-formats.html
+
+    format:
+     - rsa header
+     - modulus
+     - public_exponent
+
+    integer in big-endian format (MSB first).
+    Leading zeroes are stripped unless they are required to keep a value positive.
+  *)
+  type header = {
+    n_len: int;
+    e_len: int;
+  }
+
+  type t = {
+    header: header;
+    n: Z.t;
+    e: Z.t;
+  }
+
+  (* need to strip leading zeros or something? *)
+  let z_to_bigendian_bits v =
+    let s = Z.to_bits v in
+    let len = String.length s in
+    let s = String.init len (fun i -> s.[len - 1 - i]) in
+    s
+
+  let header_bin =
+    let open Bin in
+    record (fun n_len e_len -> { n_len; e_len })
+    |+ field beint16 (fun t -> t.n_len)
+    |+ field beint16 (fun t -> t.e_len)
+    |> sealr
+
+  (* note: this one has a dynamic sizeof *)
+  let bin =
+    let open Bin in
+    record (fun header n e ->
+        let n = Z.of_bits n in
+        let e = Z.of_bits e in
+        { header; n; e })
+    |+ field header_bin (fun t -> t.header)
+    (* TODO
+         Z.to_bits is in little endian but we need it in big endian *)
+    |+ field cstring (fun t -> z_to_bigendian_bits t.n)
+    |+ field cstring (fun t -> z_to_bigendian_bits t.e)
+    |> sealr
+
+  let of_pub ({ n; e } : Mirage_crypto_pk.Rsa.pub) =
+    let header = { n_len= Z.size n; e_len= Z.size e } in
+    let t = { header; n; e } in
+    t
+end
+
+module DenominationHash = struct
+  include HASH_64_WITH_NULL
+
+  let make (pub : Mirage_crypto_pk.Rsa.pub) =
+    pub
+    |> GNUNET_RsaPublicKey.of_pub
+    |> Bin.to_string GNUNET_RsaPublicKey.bin
+    |> hash_with_null
+end
+
 (* --- Hashes --- *)
 
 module ShortHashCode = MK_HASH_32 ()
@@ -153,7 +275,6 @@ module FullPaytoHash = MK_HASH_32 ()
 (* Hash over a normalized payto://-URI, including all optional
    fields and also with account-part canonicalized (so no BIC). *)
 module NormalizedPaytoHash = MK_HASH_32 ()
-module DenominationHash = MK_HASH_64 ()
 module PrivateContractHash = MK_HASH_64 ()
 module ExtensionsPolicyHash = MK_HASH_64 ()
 module MerchantWireHash = MK_HASH_64 ()
@@ -217,61 +338,6 @@ module EncryptedLinkSecretP = MK_64 ()
    type DenominationBlindingKeyP = string; *)
 module DenominationBlindingKeyP = MK_32 ()
 
-(* GNUNET_CRYPTO format *)
-module GNUNET_RsaPublicKey = struct
-  (* libgnuutil format:
-     https://docs.gnunet.org/doxygen/d9/dbe/structGNUNET__CRYPTO__RsaPublicKeyHeaderP.html
-     https://docs.gnunet.org/doxygen/d6/d70/group__libgnunetutil.html#ga9c99a81e8cd649c1c925d23211a0738f
-     https://www.gnupg.org/documentation/manuals/gcrypt/MPI-formats.html
-
-    format:
-     - rsa header
-     - modulus
-     - public_exponent
-
-    integer in big-endian format (MSB first).
-    Leading zeroes are stripped unless they are required to keep a value positive.
-  *)
-  type header = {
-    n_len: int;
-    e_len: int;
-  }
-
-  type t = {
-    header: header;
-    n: Z.t;
-    e: Z.t;
-  }
-
-  (* need to strip leading zeros or something? *)
-  let z_to_bigendian_bits v =
-    let s = Z.to_bits v in
-    let len = String.length s in
-    let s = String.init len (fun i -> s.[len - 1 - i]) in
-    s
-
-  let header_bin =
-    let open Bin in
-    record (fun n_len e_len -> { n_len; e_len })
-    |+ field beint16 (fun t -> t.n_len)
-    |+ field beint16 (fun t -> t.e_len)
-    |> sealr
-
-  (* note: this one has a dynamic sizeof *)
-  let bin =
-    let open Bin in
-    record (fun header n e ->
-        let n = Z.of_bits n in
-        let e = Z.of_bits e in
-        { header; n; e })
-    |+ field header_bin (fun t -> t.header)
-    (* TODO
-         Z.to_bits is in little endian but we need it in big endian *)
-    |+ field cstring (fun t -> z_to_bigendian_bits t.n)
-    |+ field cstring (fun t -> z_to_bigendian_bits t.e)
-    |> sealr
-end
-
 (* --- Various --- *)
 
 module RefreshCommitmentP = MK_64 ()