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swrup 2026-02-24 21:03:47 +01:00
parent f10791fa33
commit 74dfe2da06
2 changed files with 18 additions and 14 deletions
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20
src/fdh_rsa.ml
View file

@ -64,7 +64,12 @@ let rsa_blind pub ~bks ~msg =
let data_r_e = Z.rem (Z.mul data r_e) pub.n in let data_r_e = Z.rem (Z.mul data r_e) pub.n in
Z_extra.to_octets_be data_r_e Z_extra.to_octets_be data_r_e
(* decrypt <=> sign *)
let rsa_sign_blinded priv ~msg_blind =
Mirage_crypto_pk.Rsa.decrypt ~crt_hardening:true ~key:priv msg_blind
let rsa_unblind pub ~bks ~sig_ = let rsa_unblind pub ~bks ~sig_ =
let data = Z_extra.of_octets_be sig_ in
let bkey = rsa_blinding_key_derive pub bks in let bkey = rsa_blinding_key_derive pub bks in
let r_inv = let r_inv =
try Z.invert bkey pub.n try Z.invert bkey pub.n
@ -72,22 +77,15 @@ let rsa_unblind pub ~bks ~sig_ =
(* => gcd(r,n) <> 1, should be already checked for *) (* => gcd(r,n) <> 1, should be already checked for *)
assert false assert false
in in
let ubsig = Z.rem (Z.mul sig_ r_inv) pub.n in let data = Z.rem (Z.mul data r_inv) pub.n in
ubsig Z_extra.to_octets_be data
let rsa_sign_fdh priv msg =
let pub = RsaPrivateKey.pub_of_priv priv in
let r = rsa_full_domain_hash pub msg in
let data = Z_extra.to_octets_be r in
(* decrypt <=> sign *)
Mirage_crypto_pk.Rsa.decrypt ~crt_hardening:true ~key:priv data
(* TODO crypto (* TODO crypto
look into mirage-crypto for this look into mirage-crypto for this
at least use Eqaf for constant time string compare *) at least use Eqaf for constant time string compare *)
let rsa_verify pub ~msg ~sig_ = let rsa_verify pub ~msg ~sig_ =
let r = rsa_full_domain_hash pub msg in let msg_fdh = rsa_full_domain_hash pub msg in
let s1 = Z_extra.to_octets_be r in let s1 = Z_extra.to_octets_be msg_fdh in
let s2 = Mirage_crypto_pk.Rsa.encrypt ~key:pub sig_ in let s2 = Mirage_crypto_pk.Rsa.encrypt ~key:pub sig_ in
match String.equal s1 s2 with match String.equal s1 s2 with
| false -> Fmt.error "RSA signature verification failed" | false -> Fmt.error "RSA signature verification failed"

12
test/test_crypto.ml
View file

@ -99,12 +99,18 @@ let () =
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
in in
let open Crypto in let open Crypto in
let msg = message_hash |> decode in
let pub = let pub =
rsa_public_key |> decode |> RsaPublicKey.of_octets |> Result.get_ok rsa_public_key |> decode |> RsaPublicKey.of_octets |> Result.get_ok
in in
let bks = blinding_key_secret |> decode in let bks = blinding_key_secret |> decode in
let s = Fdh_rsa.rsa_blind pub ~bks ~msg |> encode in let msg = decode message_hash in
assert (s = blinded_message); let msg_blind = Fdh_rsa.rsa_blind pub ~bks ~msg in
assert (encode msg_blind = blinded_message);
let msg_fdh =
Mirage_crypto_pk.Z_extra.to_octets_be
@@ Fdh_rsa.rsa_full_domain_hash pub msg
in
let msg_fdh' = Fdh_rsa.rsa_unblind pub ~bks ~sig_:msg_blind in
assert (msg_fdh' = msg_fdh);
() ()