1 files changed, 70 insertions, 0 deletions
diff --git a/src/lib/pk_pad/eme_pkcs/eme_pkcs.cpp b/src/lib/pk_pad/eme_pkcs/eme_pkcs.cpp
new file mode 100644
index 000000000..0e7d1fc30
--- /dev/null
+++ b/src/lib/pk_pad/eme_pkcs/eme_pkcs.cpp
@@ -0,0 +1,70 @@
+/*
+* PKCS1 EME
+* (C) 1999-2007 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/eme_pkcs.h>
+
+namespace Botan {
+
+/*
+* PKCS1 Pad Operation
+*/
+secure_vector<byte> EME_PKCS1v15::pad(const byte in[], size_t inlen,
+                                     size_t olen,
+                                     RandomNumberGenerator& rng) const
+   {
+   olen /= 8;
+
+   if(olen < 10)
+      throw Encoding_Error("PKCS1: Output space too small");
+   if(inlen > olen - 10)
+      throw Encoding_Error("PKCS1: Input is too large");
+
+   secure_vector<byte> out(olen);
+
+   out[0] = 0x02;
+   for(size_t j = 1; j != olen - inlen - 1; ++j)
+      while(out[j] == 0)
+         out[j] = rng.next_byte();
+   buffer_insert(out, olen - inlen, in, inlen);
+
+   return out;
+   }
+
+/*
+* PKCS1 Unpad Operation
+*/
+secure_vector<byte> EME_PKCS1v15::unpad(const byte in[], size_t inlen,
+                                       size_t key_len) const
+   {
+   if(inlen != key_len / 8 || inlen < 10 || in[0] != 0x02)
+      throw Decoding_Error("PKCS1::unpad");
+
+   size_t seperator = 0;
+   for(size_t j = 0; j != inlen; ++j)
+      if(in[j] == 0)
+         {
+         seperator = j;
+         break;
+         }
+   if(seperator < 9)
+      throw Decoding_Error("PKCS1::unpad");
+
+   return secure_vector<byte>(&in[seperator + 1], &in[inlen]);
+   }
+
+/*
+* Return the max input size for a given key size
+*/
+size_t EME_PKCS1v15::maximum_input_size(size_t keybits) const
+   {
+   if(keybits / 8 > 10)
+      return ((keybits / 8) - 10);
+   else
+      return 0;
+   }
+
+}