add C API for R4 encryption

git-svn-id: svn+q:///qpdf/trunk@825 71b93d88-0707-0410-a8cf-f5a4172ac649

1 files changed, 20 insertions, 2 deletions

diff --git a/libqpdf/Pl_AES_PDF.cc b/libqpdf/Pl_AES_PDF.cc
index 0ceb7df7..d9754981 100644
--- a/libqpdf/Pl_AES_PDF.cc
+++ b/libqpdf/Pl_AES_PDF.cc
@@ -12,6 +12,8 @@
 # define srandom srand
 #endif
 
+bool Pl_AES_PDF::use_static_iv = false;
+
 Pl_AES_PDF::Pl_AES_PDF(char const* identifier, Pipeline* next,
 		       bool encrypt, unsigned char const key[key_size]) :
     Pipeline(identifier, next),
@@ -52,6 +54,12 @@ Pl_AES_PDF::disableCBC()
 }
 
 void
+Pl_AES_PDF::useStaticIV()
+{
+    use_static_iv = true;
+}
+
+void
 Pl_AES_PDF::write(unsigned char* data, int len)
 {
     unsigned int bytes_left = len;
@@ -116,9 +124,19 @@ Pl_AES_PDF::initializeVector()
 	srandom((int)QUtil::get_current_time() ^ 0xcccc);
 	seeded_random = true;
     }
-    for (unsigned int i = 0; i < this->buf_size; ++i)
+    if (use_static_iv)
+    {
+	for (unsigned int i = 0; i < this->buf_size; ++i)
+	{
+	    this->cbc_block[i] = 14 * (1 + i);
+	}
+    }
+    else
     {
-	this->cbc_block[i] = (unsigned char)((random() & 0xff0) >> 4);
+	for (unsigned int i = 0; i < this->buf_size; ++i)
+	{
+	    this->cbc_block[i] = (unsigned char)((random() & 0xff0) >> 4);
+	}
     }
 }