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-rw-r--r--CryptoPP/dsa.cpp119
1 files changed, 119 insertions, 0 deletions
diff --git a/CryptoPP/dsa.cpp b/CryptoPP/dsa.cpp
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+// 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();
+}
+
+bool DSA::GeneratePrimes(const byte *seedIn, unsigned int g, int &counter,
+ Integer &p, unsigned int L, Integer &q, bool useInputCounterValue)
+{
+ assert(g%8 == 0);
+
+ SHA sha;
+ SecByteBlock seed(seedIn, g/8);
+ SecByteBlock U(SHA::DIGESTSIZE);
+ SecByteBlock temp(SHA::DIGESTSIZE);
+ SecByteBlock W(((L-1)/160+1) * SHA::DIGESTSIZE);
+ const int n = (L-1) / 160;
+ const int b = (L-1) % 160;
+ Integer X;
+
+ sha.CalculateDigest(U, seed, g/8);
+
+ for (int i=g/8-1, carry=true; i>=0 && carry; i--)
+ carry=!++seed[i];
+
+ sha.CalculateDigest(temp, seed, g/8);
+ xorbuf(U, temp, SHA::DIGESTSIZE);
+
+ U[0] |= 0x80;
+ U[SHA::DIGESTSIZE-1] |= 1;
+ q.Decode(U, SHA::DIGESTSIZE);
+
+ if (!IsPrime(q))
+ return false;
+
+ int counterEnd = useInputCounterValue ? counter+1 : 4096;
+
+ for (int c = 0; c < counterEnd; c++)
+ {
+ for (int k=0; k<=n; k++)
+ {
+ for (int i=g/8-1, carry=true; i>=0 && carry; i--)
+ carry=!++seed[i];
+ if (!useInputCounterValue || c == counter)
+ sha.CalculateDigest(W+(n-k)*SHA::DIGESTSIZE, seed, g/8);
+ }
+ if (!useInputCounterValue || c == counter)
+ {
+ W[SHA::DIGESTSIZE - 1 - b/8] |= 0x80;
+ X.Decode(W + SHA::DIGESTSIZE - 1 - b/8, L/8);
+ p = X-((X % (2*q))-1);
+
+ if (p.GetBit(L-1) && IsPrime(p))
+ {
+ counter = c;
+ return true;
+ }
+ }
+ }
+ return false;
+}
+
+NAMESPACE_END
+
+#endif