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// dsa.cpp - originally written and placed in the public domain by Wei Dai
#include "pch.h"
#ifndef CRYPTOPP_IMPORTS
#include "dsa.h"
#include "asn.h"
#include "integer.h"
#include "filters.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
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