Add Public_Key::estimated_strength which gives an approximation of how

hard that key is to break.

Use it in cert path validation, rejecting keys with estimated strength
less than 80 bits.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/pubkey/dl_algo/dl_algo.cpp b/src/pubkey/dl_algo/dl_algo.cpp
index c90e7651e..22c432108 100644
--- a/src/pubkey/dl_algo/dl_algo.cpp
+++ b/src/pubkey/dl_algo/dl_algo.cpp
@@ -7,11 +7,17 @@
 
 #include <botan/dl_algo.h>
 #include <botan/numthry.h>
+#include <botan/internal/workfactor.h>
 #include <botan/der_enc.h>
 #include <botan/ber_dec.h>
 
 namespace Botan {
 
+size_t DL_Scheme_PublicKey::estimated_strength() const
+   {
+   return dl_work_factor(group.get_p().bits());
+   }
+
 AlgorithmIdentifier DL_Scheme_PublicKey::algorithm_identifier() const
    {
    return AlgorithmIdentifier(get_oid(),