Support decoding of ECC groups with seed parameter

Closes GH #874

3 files changed, 29 insertions, 0 deletions

diff --git a/src/lib/pubkey/ec_group/ec_group.cpp b/src/lib/pubkey/ec_group/ec_group.cpp
index 6064f869c..9da1cd81f 100644
--- a/src/lib/pubkey/ec_group/ec_group.cpp
+++ b/src/lib/pubkey/ec_group/ec_group.cpp
@@ -264,6 +264,7 @@ std::shared_ptr<EC_Group_Data> EC_Group::BER_decode_EC_group(const uint8_t bits[
       {
       BigInt p, a, b, order, cofactor;
       std::vector<uint8_t> base_pt;
+      std::vector<uint8_t> seed;
 
       BER_Decoder(bits, len)
          .start_cons(SEQUENCE)
@@ -276,6 +277,7 @@ std::shared_ptr<EC_Group_Data> EC_Group::BER_decode_EC_group(const uint8_t bits[
            .start_cons(SEQUENCE)
              .decode_octet_string_bigint(a)
              .decode_octet_string_bigint(b)
+             .decode_optional_string(seed, BIT_STRING, BIT_STRING)
            .end_cons()
            .decode(base_pt, OCTET_STRING)
            .decode(order)
diff --git a/src/tests/data/x509/ecc/secp384r1_seed.pem b/src/tests/data/x509/ecc/secp384r1_seed.pem
new file mode 100644
index 000000000..8f5598ed0
--- /dev/null
+++ b/src/tests/data/x509/ecc/secp384r1_seed.pem
@@ -0,0 +1,10 @@
+-----BEGIN EC PARAMETERS-----
+MIIBVwIBATA8BgcqhkjOPQEBAjEA////////////////////////////////////
+//////7/////AAAAAAAAAAD/////MHsEMP//////////////////////////////
+///////////+/////wAAAAAAAAAA/////AQwszEvp+I+5+SYjgVr4/gtGRgdnG7+
+gUESAxQIj1ATh1rGVjmNii7RnSqFyO3T7CrvAxUAozWSaqMZonodAIlqZ3OkgnrN
+rHMEYQSqh8oivosFN46xxx7zIK10bh07Younm5hZ90HgglQqOFUC8l2/VSlsOlRe
+OHJ2Crc2F95KliYsb12emL+Sktwp+PQdvSiaFHzp2jETtfC4wApgsc4dfoGdekMd
+fJDqDl8CMQD////////////////////////////////HY02B9Dct31gaDbJIsKd6
+7OwZaszFKXMCAQE=
+-----END EC PARAMETERS-----
diff --git a/src/tests/unit_ecc.cpp b/src/tests/unit_ecc.cpp
index aecf6e5d4..6f0d1a243 100644
--- a/src/tests/unit_ecc.cpp
+++ b/src/tests/unit_ecc.cpp
@@ -293,6 +293,22 @@ Test::Result test_groups()
    return result;
    }
 
+Test::Result test_decoding_with_seed()
+   {
+   Test::Result result("ECC Unit");
+
+   Botan::EC_Group secp384r1_with_seed(
+      Test::read_data_file("x509/ecc/secp384r1_seed.pem"));
+
+   result.confirm("decoding worked", secp384r1_with_seed.initialized());
+
+   Botan::EC_Group secp384r1("secp384r1");
+
+   result.test_eq("P-384 prime", secp384r1_with_seed.get_p(), secp384r1.get_p());
+
+   return result;
+   }
+
 Test::Result test_coordinates()
    {
    Test::Result result("ECC Unit");
@@ -765,6 +781,7 @@ class ECC_Unit_Tests final : public Test
 
          results.push_back(test_groups());
          results.push_back(test_coordinates());
+         results.push_back(test_decoding_with_seed());
          results.push_back(test_point_transformation());
          results.push_back(test_point_mult());
          results.push_back(test_point_negative());