diff options
Diffstat (limited to 'src/lib/pubkey/dl_group/dl_group.cpp')
| -rw-r--r-- | src/lib/pubkey/dl_group/dl_group.cpp | 23 |
1 files changed, 19 insertions, 4 deletions
diff --git a/src/lib/pubkey/dl_group/dl_group.cpp b/src/lib/pubkey/dl_group/dl_group.cpp index adf207b43..6d7f0b107 100644 --- a/src/lib/pubkey/dl_group/dl_group.cpp +++ b/src/lib/pubkey/dl_group/dl_group.cpp @@ -29,9 +29,9 @@ DL_Group::DL_Group() */ DL_Group::DL_Group(const std::string& name) { - const char* pem = PEM_for_named_group(name); + const std::string pem = PEM_for_named_group(name); - if(!pem) + if(pem == "") throw Invalid_Argument("DL_Group: Unknown group " + name); PEM_decode(pem); @@ -52,6 +52,21 @@ DL_Group::DL_Group(RandomNumberGenerator& rng, m_p = random_safe_prime(rng, pbits); m_q = (m_p - 1) / 2; m_g = 2; + + /* + Always choose a generator that is quadratic reside mod p, + this forces g to be a generator of the subgroup of size q. + */ + if(jacobi(m_g, m_p) != 1) + { + // prime table does not contain 2 + for(size_t i = 0; i < PRIME_TABLE_SIZE; ++i) + { + m_g = PRIMES[i]; + if(jacobi(m_g, m_p) == 1) + break; + } + } } else if(type == Prime_Subgroup) { @@ -259,7 +274,7 @@ std::string DL_Group::PEM_encode(Format format) const else if(format == ANSI_X9_57) return PEM_Code::encode(encoding, "DSA PARAMETERS"); else if(format == ANSI_X9_42) - return PEM_Code::encode(encoding, "X942 DH PARAMETERS"); + return PEM_Code::encode(encoding, "X9.42 DH PARAMETERS"); else throw Invalid_Argument("Unknown DL_Group encoding " + std::to_string(format)); } @@ -314,7 +329,7 @@ void DL_Group::PEM_decode(const std::string& pem) BER_decode(ber, PKCS_3); else if(label == "DSA PARAMETERS") BER_decode(ber, ANSI_X9_57); - else if(label == "X942 DH PARAMETERS") + else if(label == "X942 DH PARAMETERS" || label == "X9.42 DH PARAMETERS") BER_decode(ber, ANSI_X9_42); else throw Decoding_Error("DL_Group: Invalid PEM label " + label); |