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swrup 2026-02-13 17:15:04 +01:00
parent 03fef73233
commit e039bf0b16
1 changed files with 0 additions and 46 deletions
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46
src/fdh.ml
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@ -7,49 +7,3 @@ module Kdf = struct
let okm = PRF.expand ~prk ~info:ctx len in let okm = PRF.expand ~prk ~info:ctx len in
okm okm
end end
(* WIP
let kdf_mod_n ~n ~xts ~ikm ~ctx =
let nbits = Z.numbits n in
let rec go ctr =
let len = ((nbits - 1) / 8) + 1 in
let ctr_be =
let b = Bytes.create 2 in
Bytes.set_uint16_be b 0 ctr;
Bytes.unsafe_to_string b
in
let ctx = String.cat ctx ctr_be in
let okm = Kdf.kdf ~xts ~ikm ~ctx ~len in
let r = Z.of_bits okm in
(* we do that because n is odd?
TODO
gcry_mpi_clear_highbit .. *)
if Z.gt r n then go (succ ctr) else r
in
go 0
let rsa_full_domain_hash pub msg =
let xts = RsaPublicKey.to_octets pub in
let ctx = "RSA-FDA FTpsW!" in
let r = kdf_mod_n ~n:pub.n ~xts ~ikm:msg ~ctx in
r
let rsa_sign_fdh priv msg =
let pub = Mirage_crypto_pk.Rsa.pub_of_priv priv in
let v = rsa_full_domain_hash pub msg in
let v = Z.to_bits v in
Mirage_crypto_pk.Rsa.PKCS1.sig_encode ~crt_hardening:true ~key:priv v
let rsa_blinding_key_derive (pub : RsaPublicKey.t) bks =
let xts = "Blinding KDF extractor HMAC key" in
let ctx = "Blinding KDF" in
let r = kdf_mod_n ~n:pub.n ~xts ~ikm:bks ~ctx in
r
let rsa_blind pub ~bks ~msg =
let data = rsa_full_domain_hash pub msg in
let bkey = rsa_blinding_key_derive pub bks in
let r_e = Z.powm bkey pub.e pub.n in
let data_r_e = Z.rem (Z.mul data r_e) pub.n in
Z.to_bits data_r_e
*)