Expose DSA bits in key parameters

src/info.rs

@@ -238,6 +238,7 @@ pub(crate) fn empty_public_params_info(kind: &str) -> PublicParamsInfo {
         curve_oid: None,
         curve_alias: None,
         curve_bits: None,
+        dsa_bits: None,
         rsa_bits: None,
         secret_key_length: None,
         is_supported: None,
@@ -263,6 +264,9 @@ pub(crate) fn public_params_info_from_params(params: &PgpPublicParams) -> Public
         PgpPublicParams::RSA(params) => {
             info.rsa_bits = u32::try_from(params.key.n().bits()).ok();
         }
+        PgpPublicParams::DSA(params) => {
+            info.dsa_bits = u32::try_from(params.key.components().p().bits()).ok();
+        }
         PgpPublicParams::ECDSA(params) => match params {
             PgpEcdsaPublicParams::P256 { .. } => {
                 set_curve_metadata(&mut info, &ECCCurve::P256);
@@ -927,6 +931,7 @@ pub(crate) struct PublicParamsInfo {
     pub(crate) curve_oid: Option<String>,
     pub(crate) curve_alias: Option<String>,
     pub(crate) curve_bits: Option<u16>,
+    pub(crate) dsa_bits: Option<u32>,
     pub(crate) rsa_bits: Option<u32>,
     pub(crate) secret_key_length: Option<usize>,
     pub(crate) is_supported: Option<bool>,
@@ -967,6 +972,11 @@ impl PublicParamsInfo {
         self.curve_bits
     }
 
+    #[getter]
+    fn dsa_bits(&self) -> Option<u32> {
+        self.dsa_bits
+    }
+
     /// The encoded RSA modulus size in bits, when this key uses RSA public parameters.
     #[getter]
     fn rsa_bits(&self) -> Option<u32> {

src/openpgp/_openpgp.pyi

@@ -260,6 +260,8 @@ class PublicParamsInfo:
     @property
     def curve_bits(self) -> Optional[int]: ...
     @property
+    def dsa_bits(self) -> Optional[int]: ...
+    @property
     def rsa_bits(self) -> Optional[int]: ...
     @property
     def secret_key_length(self) -> Optional[int]: ...

tests/test_key_generation.py

@@ -379,6 +379,34 @@ def test_legacy_curve25519_public_params_expose_curve_metadata() -> None:
     assert reparsed_public.subkey_bindings()[0].public_params.curve == "curve25519"
 
 
+def test_dsa_public_params_expose_prime_size_for_generated_and_parsed_keys() -> None:
+    secret_key = (
+        SecretKeyParamsBuilder()
+        .created_at(FIXED_PRIMARY_CREATED_AT)
+        .key_type(KeyType.dsa(1024))
+        .can_certify(True)
+        .can_sign(True)
+        .primary_user_id("alice")
+        .build()
+        .generate()
+    )
+    public_key = secret_key.to_public_key()
+
+    for key in (secret_key, public_key):
+        params = key.public_params
+        assert params.kind == "dsa"
+        assert params.dsa_bits == 1024
+        assert params.rsa_bits is None
+        assert params.curve is None
+        assert params.curve_bits is None
+        assert params.secret_key_length is None
+
+    reparsed_secret, _ = SecretKey.from_armor(secret_key.to_armored())
+    reparsed_public, _ = PublicKey.from_armor(public_key.to_armored())
+    assert reparsed_secret.public_params.dsa_bits == 1024
+    assert reparsed_public.public_params.dsa_bits == 1024
+
+
 def test_rsa_public_params_expose_modulus_size_for_generated_and_parsed_keys() -> None:
     secret_key = (
         SecretKeyParamsBuilder()
@@ -396,6 +424,7 @@ def test_rsa_public_params_expose_modulus_size_for_generated_and_parsed_keys() -
         params = key.public_params
         assert params.kind == "rsa"
         assert params.rsa_bits == 2048
+        assert params.dsa_bits is None
         assert params.curve is None
         assert params.curve_bits is None
         assert params.secret_key_length is None