got working aes128 implementation

git-svn-id: svn+q:///qpdf/trunk@809 71b93d88-0707-0410-a8cf-f5a4172ac649

got working aes128 implementation
git-svn-id: svn+q:///qpdf/trunk@809 71b93d88-0707-0410-a8cf-f5a4172ac649
Jay Berkenbilt
1 parent 2c3b6a5c
Showing 6 changed files with 63 additions and 22 deletions
README
libqpdf/Pl_AES_PDF.cc
libqpdf/build.mk
libqpdf/qpdf/Pl_AES_PDF.hh
libqpdf/qpdf/rijndael.h
libqpdf/rijndael.cc
@@ -33,6 +33,15 @@ The sources to PCRE can be independently obtained from
    ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/
+The Rijndael encryption implementation used as the basis for AES
+encryption and decryption support comes from Philip J. Erdelsky's
+public domain implementation.  The files libqpdf/rijndael.cc and
+libqpdf/qpdf/rijndael.h remain in the public domain.  They were
+obtained from
+
+  http://www.efgh.com/software/rijndael.htm
+  http://www.efgh.com/software/rijndael.txt
+
 Building on UNIX/Linux
 ======================
@@ -3,20 +3,38 @@
 #include <cstring>
 #include <assert.h>
 #include <stdexcept>
+#include <qpdf/rijndael.h>
+
+// XXX Still need CBC
 Pl_AES_PDF::Pl_AES_PDF(char const* identifier, Pipeline* next,
-		       bool encrypt, unsigned char* key_data) :
+		       bool encrypt, unsigned char key[key_size]) :
     Pipeline(identifier, next),
     encrypt(encrypt),
-    offset(0)
+    offset(0),
+    nrounds(0)
 {
-    std::memset(this->buf, 0, this->buf_size);
-    // XXX init
+    static int const keybits = 128;
+    assert(key_size == KEYLENGTH(keybits));
+    assert(sizeof(this->rk) / sizeof(uint32_t) == RKLENGTH(keybits));
+    std::memcpy(this->key, key, key_size);
+    std::memset(this->rk, 0, sizeof(this->rk));
+    std::memset(this->inbuf, 0, this->buf_size);
+    std::memset(this->outbuf, 0, this->buf_size);
+    if (encrypt)
+    {
+	this->nrounds = rijndaelSetupEncrypt(this->rk, this->key, keybits);
+    }
+    else
+    {
+	this->nrounds = rijndaelSetupDecrypt(this->rk, this->key, keybits);
+    }
+    assert(this->nrounds == NROUNDS(keybits));
 }
 Pl_AES_PDF::~Pl_AES_PDF()
 {
-    // XXX finalize
+    // nothing needed
 }
 void
@@ -35,7 +53,7 @@ Pl_AES_PDF::write(unsigned char* data, int len)
 	unsigned int available = this->buf_size - this->offset;
 	int bytes = (bytes_left < available ? bytes_left : available);
 	bytes_left -= bytes;
-	std::memcpy(this->buf + this->offset, p, bytes);
+	std::memcpy(this->inbuf + this->offset, p, bytes);
 	this->offset += bytes;
 	p += bytes;
     }
@@ -54,7 +72,7 @@ Pl_AES_PDF::finish()
 	// specification, including providing an entire block of padding
 	// if the input was a multiple of 16 bytes.
 	unsigned char pad = this->buf_size - this->offset;
-	memset(this->buf + this->offset, pad, pad);
+	memset(this->inbuf + this->offset, pad, pad);
 	this->offset = this->buf_size;
 	flush(false);
     }
@@ -78,22 +96,22 @@ Pl_AES_PDF::flush(bool strip_padding)
     assert(this->offset == this->buf_size);
     if (this->encrypt)
     {
-	// XXX encrypt this->buf
+	rijndaelEncrypt(this->rk, this->nrounds, this->inbuf, this->outbuf);
     }
     else
     {
-	// XXX decrypt this->buf
+	rijndaelDecrypt(this->rk, this->nrounds, this->inbuf, this->outbuf);
     }
     unsigned int bytes = this->buf_size;
     if (strip_padding)
     {
-	unsigned char last = this->buf[this->buf_size - 1];
+	unsigned char last = this->outbuf[this->buf_size - 1];
 	if (last <= this->buf_size)
 	{
 	    bool strip = true;
 	    for (unsigned int i = 1; i <= last; ++i)
 	    {
-		if (this->buf[this->buf_size - i] != last)
+		if (this->outbuf[this->buf_size - i] != last)
 		{
 		    strip = false;
 		    break;
@@ -105,6 +123,6 @@ Pl_AES_PDF::flush(bool strip_padding)
 	    }
 	}
     }
-    getNext()->write(this->buf, bytes);
+    getNext()->write(this->outbuf, bytes);
     this->offset = 0;
 }
@@ -48,7 +48,8 @@ SRCS_libqpdf = \
 	libqpdf/QTC.cc \
 	libqpdf/QUtil.cc \
 	libqpdf/RC4.cc \
-	libqpdf/qpdf-c.cc
+	libqpdf/qpdf-c.cc \
+	libqpdf/rijndael.cc
 # -----
@@ -3,13 +3,16 @@
 #include <qpdf/Pipeline.hh>
+// This pipeline implements AES-128 with CBC and block padding as
+// specified in the PDF specification.
+
 class DLL_EXPORT Pl_AES_PDF: public Pipeline
 {
   public:
     // key_data should be a pointer to key_size bytes of data
     static unsigned int const key_size = 16;
     Pl_AES_PDF(char const* identifier, Pipeline* next,
-	       bool encrypt, unsigned char* key_data);
+	       bool encrypt, unsigned char key[key_size]);
     virtual ~Pl_AES_PDF();
     virtual void write(unsigned char* data, int len);
@@ -18,10 +21,15 @@ class DLL_EXPORT Pl_AES_PDF: public Pipeline
   private:
     void flush(bool discard_padding);
+    static unsigned int const buf_size = 16;
+
     bool encrypt;
     unsigned int offset;
-    static unsigned int const buf_size = 16;
-    unsigned char buf[buf_size];
+    unsigned char key[key_size];
+    uint32_t rk[key_size + 28];
+    unsigned char inbuf[buf_size];
+    unsigned char outbuf[buf_size];
+    unsigned int nrounds;
 };
 #endif // __PL_AES_PDF_HH__
 #ifndef H__RIJNDAEL
 #define H__RIJNDAEL
-int rijndaelSetupEncrypt(unsigned long *rk, const unsigned char *key,
+#include <qpdf/qpdf-config.h>
+#ifdef HAVE_INTTYPES_H
+# include <inttypes.h>
+#endif
+
+int rijndaelSetupEncrypt(uint32_t *rk, const unsigned char *key,
   int keybits);
-int rijndaelSetupDecrypt(unsigned long *rk, const unsigned char *key,
+int rijndaelSetupDecrypt(uint32_t *rk, const unsigned char *key,
   int keybits);
-void rijndaelEncrypt(const unsigned long *rk, int nrounds,
+void rijndaelEncrypt(const uint32_t *rk, int nrounds,
   const unsigned char plaintext[16], unsigned char ciphertext[16]);
-void rijndaelDecrypt(const unsigned long *rk, int nrounds,
+void rijndaelDecrypt(const uint32_t *rk, int nrounds,
   const unsigned char ciphertext[16], unsigned char plaintext[16]);
 #define KEYLENGTH(keybits) ((keybits)/8)
 #define FULL_UNROLL
-#include "rijndael.h"
+#include "qpdf/rijndael.h"
-typedef unsigned long u32;
+typedef uint32_t u32;
 typedef unsigned char u8;
 static const u32 Te0[256] =