Add Propagating CBC (PCBC) mode

[tfcrypt.git] / tfpcbc.c

diff --git a/tfpcbc.c b/tfpcbc.c
new file mode 100644 (file)
index 0000000..72ac9a3
--- /dev/null
+++ b/tfpcbc.c
@@ -0,0 +1,86 @@
+#include <string.h>
+#include "tfdef.h"
+
+void tf_pcbc_encrypt(const void *key, void *iv, void *out, const void *in, size_t sz)
+{
+       const TF_BYTE_TYPE *uin = (const TF_BYTE_TYPE *)in;
+       TF_BYTE_TYPE *uout = (TF_BYTE_TYPE *)out;
+       TF_UNIT_TYPE x[TF_NR_BLOCK_UNITS], y[TF_NR_BLOCK_UNITS];
+       TF_UNIT_TYPE *uiv = (TF_UNIT_TYPE *)iv;
+       const TF_UNIT_TYPE *ukey = (const TF_UNIT_TYPE *)key;
+       size_t sl = sz, i;
+
+       if (sl >= TF_BLOCK_SIZE) {
+               do {
+                       memcpy(x, uin, TF_BLOCK_SIZE);
+                       uin += TF_BLOCK_SIZE;
+                       data_to_words(x, TF_BLOCK_SIZE);
+
+                       for (i = 0; i < TF_NR_BLOCK_UNITS; i++) y[i] = x[i] ^ uiv[i];
+                       tf_encrypt_rawblk(y, y, ukey);
+                       for (i = 0; i < TF_NR_BLOCK_UNITS; i++) uiv[i] = y[i] ^ x[i];
+
+                       data_to_words(y, TF_BLOCK_SIZE);
+                       memcpy(uout, y, TF_BLOCK_SIZE);
+                       uout += TF_BLOCK_SIZE;
+               } while ((sl -= TF_BLOCK_SIZE) >= TF_BLOCK_SIZE);
+       }
+
+       if (sl) {
+               memset(x, 0, TF_BLOCK_SIZE);
+               memcpy(x, uin, sl);
+               data_to_words(x, TF_BLOCK_SIZE);
+
+               ctr_inc(uiv, TF_NR_BLOCK_UNITS);
+               tf_encrypt_rawblk(y, uiv, ukey);
+               for (i = 0; i < TF_NR_BLOCK_UNITS; i++) y[i] ^= x[i];
+
+               data_to_words(y, TF_BLOCK_SIZE);
+               memcpy(uout, y, sl);
+       }
+
+       memset(x, 0, TF_BLOCK_SIZE);
+       memset(y, 0, TF_BLOCK_SIZE);
+}
+
+void tf_pcbc_decrypt(const void *key, void *iv, void *out, const void *in, size_t sz)
+{
+       const TF_BYTE_TYPE *uin = (const TF_BYTE_TYPE *)in;
+       TF_BYTE_TYPE *uout = (TF_BYTE_TYPE *)out;
+       TF_UNIT_TYPE x[TF_NR_BLOCK_UNITS], y[TF_NR_BLOCK_UNITS];
+       TF_UNIT_TYPE *uiv = (TF_UNIT_TYPE *)iv;
+       const TF_UNIT_TYPE *ukey = (const TF_UNIT_TYPE *)key;
+       size_t sl = sz, i;
+
+       if (sl >= TF_BLOCK_SIZE) {
+               do {
+                       memcpy(x, uin, TF_BLOCK_SIZE);
+                       uin += TF_BLOCK_SIZE;
+                       data_to_words(x, TF_BLOCK_SIZE);
+
+                       tf_decrypt_rawblk(y, x, ukey);
+                       for (i = 0; i < TF_NR_BLOCK_UNITS; i++) y[i] ^= uiv[i];
+                       for (i = 0; i < TF_NR_BLOCK_UNITS; i++) uiv[i] = y[i] ^ x[i];
+
+                       data_to_words(y, TF_BLOCK_SIZE);
+                       memcpy(uout, y, TF_BLOCK_SIZE);
+                       uout += TF_BLOCK_SIZE;
+               } while ((sl -= TF_BLOCK_SIZE) >= TF_BLOCK_SIZE);
+       }
+
+       if (sl) {
+               memset(x, 0, TF_BLOCK_SIZE);
+               memcpy(x, uin, sl);
+               data_to_words(x, TF_BLOCK_SIZE);
+
+               ctr_inc(uiv, TF_NR_BLOCK_UNITS);
+               tf_encrypt_rawblk(y, uiv, ukey);
+               for (i = 0; i < TF_NR_BLOCK_UNITS; i++) y[i] ^= x[i];
+
+               data_to_words(y, TF_BLOCK_SIZE);
+               memcpy(uout, y, sl);
+       }
+
+       memset(x, 0, TF_BLOCK_SIZE);
+       memset(y, 0, TF_BLOCK_SIZE);
+}