1 files changed, 63 insertions, 0 deletions

diff --git a/lib/cryptopp/dsa.cpp b/lib/cryptopp/dsa.cpp
new file mode 100644
index 000000000..5aace4857
--- /dev/null
+++ b/lib/cryptopp/dsa.cpp
@@ -0,0 +1,63 @@
+// dsa.cpp - written and placed in the public domain by Wei Dai
+
+#include "pch.h"
+
+#ifndef CRYPTOPP_IMPORTS
+
+#include "dsa.h"
+#include "nbtheory.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+size_t DSAConvertSignatureFormat(byte *buffer, size_t bufferSize, DSASignatureFormat toFormat, const byte *signature, size_t signatureLen, DSASignatureFormat fromFormat)
+{
+	Integer r, s;
+	StringStore store(signature, signatureLen);
+	ArraySink sink(buffer, bufferSize);
+
+	switch (fromFormat)
+	{
+	case DSA_P1363:
+		r.Decode(store, signatureLen/2);
+		s.Decode(store, signatureLen/2);
+		break;
+	case DSA_DER:
+	{
+		BERSequenceDecoder seq(store);
+		r.BERDecode(seq);
+		s.BERDecode(seq);
+		seq.MessageEnd();
+		break;
+	}
+	case DSA_OPENPGP:
+		r.OpenPGPDecode(store);
+		s.OpenPGPDecode(store);
+		break;
+	}
+
+	switch (toFormat)
+	{
+	case DSA_P1363:
+		r.Encode(sink, bufferSize/2);
+		s.Encode(sink, bufferSize/2);
+		break;
+	case DSA_DER:
+	{
+		DERSequenceEncoder seq(sink);
+		r.DEREncode(seq);
+		s.DEREncode(seq);
+		seq.MessageEnd();
+		break;
+	}
+	case DSA_OPENPGP:
+		r.OpenPGPEncode(sink);
+		s.OpenPGPEncode(sink);
+		break;
+	}
+
+	return (size_t)sink.TotalPutLength();
+}
+
+NAMESPACE_END
+
+#endif