Add two more constructors to AlgorithmIdentifier, which take a

Encoding_Option enum that can specify various options. Right now the
only one supported/available is USE_NULL_PARAM, to set the parameters
to a DER-encoded NULL object 

2 files changed, 41 insertions, 4 deletions

diff --git a/include/asn1_obj.h b/include/asn1_obj.h
index 7bb6ac8a3..4397d2fc3 100644
--- a/include/asn1_obj.h
+++ b/include/asn1_obj.h
@@ -19,10 +19,15 @@ namespace Botan {
 class AlgorithmIdentifier : public ASN1_Object
    {
    public:
+      enum Encoding_Option { USE_NULL_PARAM };
+
       void encode_into(class DER_Encoder&) const;
       void decode_from(class BER_Decoder&);
 
       AlgorithmIdentifier() {}
+      AlgorithmIdentifier(const OID&, Encoding_Option);
+      AlgorithmIdentifier(const std::string&, Encoding_Option);
+
       AlgorithmIdentifier(const OID&, const MemoryRegion<byte>&);
       AlgorithmIdentifier(const std::string&, const MemoryRegion<byte>&);
 
diff --git a/src/asn1_alg.cpp b/src/asn1_alg.cpp
index 251c8c31f..7f54b2fa5 100644
--- a/src/asn1_alg.cpp
+++ b/src/asn1_alg.cpp
@@ -14,15 +14,47 @@ namespace Botan {
 * Create an AlgorithmIdentifier                  *
 *************************************************/
 AlgorithmIdentifier::AlgorithmIdentifier(const OID& alg_id,
-                                         const MemoryRegion<byte>& param) :
-   oid(alg_id), parameters(param) { }
+                                         const MemoryRegion<byte>& param)
+   {
+   oid = alg_id;
+   parameters = param;
+   }
+
+/*************************************************
+* Create an AlgorithmIdentifier                  *
+*************************************************/
+AlgorithmIdentifier::AlgorithmIdentifier(const std::string& alg_id,
+                                         const MemoryRegion<byte>& param)
+   {
+   oid = OIDS::lookup(alg_id);
+   parameters = param;
+   }
+
+/*************************************************
+* Create an AlgorithmIdentifier                  *
+*************************************************/
+AlgorithmIdentifier::AlgorithmIdentifier(const OID& alg_id,
+                                         Encoding_Option option)
+   {
+   const byte DER_NULL[] = { 0x05, 0x00 };
+
+   oid = alg_id;
+   if(option == USE_NULL_PARAM)
+      parameters.append(DER_NULL, sizeof(DER_NULL));
+   }
 
 /*************************************************
 * Create an AlgorithmIdentifier                  *
 *************************************************/
 AlgorithmIdentifier::AlgorithmIdentifier(const std::string& alg_id,
-                                         const MemoryRegion<byte>& param) :
-   oid(OIDS::lookup(alg_id)), parameters(param) { }
+                                         Encoding_Option option)
+   {
+   const byte DER_NULL[] = { 0x05, 0x00 };
+
+   oid = OIDS::lookup(alg_id);
+   if(option == USE_NULL_PARAM)
+      parameters.append(DER_NULL, sizeof(DER_NULL));
+   }
 
 /*************************************************
 * Compare two AlgorithmIdentifiers               *