Add implementation and test for AES CTR mode.

aes.h

@@ -75,3 +75,18 @@ void aes_cbc_decrypt(struct aes_context *context,
                      unsigned char *out,
                      unsigned long nblocks,
                      const unsigned char *iv);
+
+/*
+ * Process data using AES-128, AES-192, or AES-256 in CTR mode.
+ * This either encrypts or decrypts data, depending on whether
+ * in contains plaintext or ciphertext.
+ * The key must have been specified via aes{128,192,256}_expandkey().
+ * nblocks gives the number of 16-byte blocks to be processed.
+ * counter will be interpreted as a 128-bit big-endian integer,
+ * and incremented for each block processed.
+ */
+void aes_ctr_process(struct aes_context *context,
+                     const unsigned char *in,
+                     unsigned char *out,
+                     unsigned long nblocks,
+                     const unsigned char *counter);

aesctrtest.c

@@ -0,0 +1,126 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <Memory.h>
+#include <MiscTool.h>
+#include <orca.h>
+#include "aes.h"
+
+unsigned char initial_counter[16] = {
+    0xf0,0xf1,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7,
+    0xf8,0xf9,0xfa,0xfb,0xfc,0xfd,0xfe,0xff
+};
+
+unsigned char counter[16];
+
+unsigned char key128[16] = {
+    0x2b,0x7e,0x15,0x16,0x28,0xae,0xd2,0xa6,
+    0xab,0xf7,0x15,0x88,0x09,0xcf,0x4f,0x3c
+};
+
+unsigned char key192[24] = {
+    0x8e,0x73,0xb0,0xf7,0xda,0x0e,0x64,0x52,
+    0xc8,0x10,0xf3,0x2b,0x80,0x90,0x79,0xe5,
+    0x62,0xf8,0xea,0xd2,0x52,0x2c,0x6b,0x7b
+};
+
+unsigned char key256[32] = {
+    0x60,0x3d,0xeb,0x10,0x15,0xca,0x71,0xbe,
+    0x2b,0x73,0xae,0xf0,0x85,0x7d,0x77,0x81,
+    0x1f,0x35,0x2c,0x07,0x3b,0x61,0x08,0xd7,
+    0x2d,0x98,0x10,0xa3,0x09,0x14,0xdf,0xf4
+};
+
+unsigned char plaintext[64] = {
+    0x6b,0xc1,0xbe,0xe2,0x2e,0x40,0x9f,0x96,
+    0xe9,0x3d,0x7e,0x11,0x73,0x93,0x17,0x2a,
+    0xae,0x2d,0x8a,0x57,0x1e,0x03,0xac,0x9c,
+    0x9e,0xb7,0x6f,0xac,0x45,0xaf,0x8e,0x51,
+    0x30,0xc8,0x1c,0x46,0xa3,0x5c,0xe4,0x11,
+    0xe5,0xfb,0xc1,0x19,0x1a,0x0a,0x52,0xef,
+    0xf6,0x9f,0x24,0x45,0xdf,0x4f,0x9b,0x17,
+    0xad,0x2b,0x41,0x7b,0xe6,0x6c,0x37,0x10
+};
+
+unsigned char output[64];
+unsigned char output2[64];
+
+#define BUFSIZE 64000
+
+static void printhex(char *str, unsigned char *buf, unsigned int count) {
+    unsigned int i;
+
+    if (str)
+        printf("%s\n", str);
+
+    for (i = 0; i < count; i++) {
+        printf("%02x", buf[i]);
+        if (i && (i & 0x0F) == 0x0F)
+            printf("\n");
+    }
+}
+
+int main(void) {
+    struct aes_context **context_hndl;
+    struct aes_context *context;
+    unsigned char *inbuf, *outbuf;
+    unsigned long tick_count;
+    long double bytes_per_sec;
+
+    context_hndl = (struct aes_context **)NewHandle(sizeof(struct aes_context),
+                userid(), attrFixed|attrPage|attrBank|attrNoCross, 0x000000);
+    if (toolerror())
+        return 0;
+    context = *context_hndl;
+    
+    memcpy(context->key, key128, 16);
+    aes128_expandkey(context);
+    
+    memcpy(counter, initial_counter, 16);
+    aes_ctr_process(context, plaintext, output, 4, counter);
+    printhex("AES-128 ciphertext:", output, 64);
+    
+    memcpy(counter, initial_counter, 16);
+    aes_ctr_process(context, output, output2, 4, counter);
+    printhex("Decrypted plaintext:", output2, 64);
+
+    
+    memcpy(context->key, key192, 24);
+    aes192_expandkey(context);
+    
+    memcpy(counter, initial_counter, 16);
+    aes_ctr_process(context, plaintext, output, 4, counter);
+    printhex("AES-192 ciphertext:", output, 64);
+    
+    memcpy(counter, initial_counter, 16);
+    aes_ctr_process(context, output, output2, 4, counter);
+    printhex("Decrypted plaintext:", output2, 64);
+
+
+    memcpy(context->key, key256, 32);
+    aes256_expandkey(context);
+    
+    memcpy(counter, initial_counter, 16);
+    aes_ctr_process(context, plaintext, output, 4, counter);
+    printhex("AES-256 ciphertext:", output, 64);
+    
+    memcpy(counter, initial_counter, 16);
+    aes_ctr_process(context, output, output2, 4, counter);
+    printhex("Decrypted plaintext:", output2, 64);
+    
+    /* Timing tests */
+    inbuf = calloc(BUFSIZE, 1);
+    outbuf = malloc(BUFSIZE);
+    if (inbuf == NULL || outbuf == NULL)
+        return -1;
+    
+    memcpy(context->key, key128, 16);
+    aes128_expandkey(context);
+    memcpy(counter, initial_counter, 16);
+    
+    tick_count = GetTick();
+    aes_ctr_process(context, inbuf, outbuf, BUFSIZE / 16, counter);
+    tick_count = GetTick() - tick_count;
+    bytes_per_sec = (long double)BUFSIZE * 60 / tick_count;
+    printf("AES-128 CTR encryption/decryption: %lf bytes/sec\n", bytes_per_sec);
+}

aesmodes.c

@@ -281,3 +281,112 @@ void aes_cbc_decrypt(struct aes_context *context,
         out += 16;
     }
 }
+
+/*
+ * Process data using AES-128, AES-192, or AES-256 in CTR mode.
+ * This either encrypts or decrypts data, depending on whether
+ * in contains plaintext or ciphertext.
+ * The key must have been specified via aes{128,192,256}_expandkey().
+ * nblocks gives the number of 16-byte blocks to be processed.
+ * counter will be interpreted as a 128-bit big-endian integer,
+ * and incremented for each block processed.
+ */
+void aes_ctr_process(struct aes_context *context,
+                     const unsigned char *in,
+                     unsigned char *out,
+                     unsigned long nblocks,
+                     const unsigned char *counter)
+{
+    while (nblocks-- > 0) {
+        asm {
+            lda [counter]
+            sta [context]
+            ldy #2
+            lda [counter],y
+            sta [context],y
+            iny
+            iny
+            lda [counter],y
+            sta [context],y
+            iny
+            iny
+            lda [counter],y
+            sta [context],y
+            iny
+            iny
+            lda [counter],y
+            sta [context],y
+            iny
+            iny
+            lda [counter],y
+            sta [context],y
+            iny
+            iny
+            lda [counter],y
+            sta [context],y
+            iny
+            iny
+            lda [counter],y
+            sta [context],y
+            
+            phd
+            lda context
+            tcd
+            jsl AES_ENCRYPT
+            pld
+        
+            lda [context]
+            eor [in]
+            sta [out]
+            ldy #2
+            lda [context],y
+            eor [in],y
+            sta [out],y
+            iny
+            iny
+            lda [context],y
+            eor [in],y
+            sta [out],y
+            iny
+            iny
+            lda [context],y
+            eor [in],y
+            sta [out],y
+            iny
+            iny
+            lda [context],y
+            eor [in],y
+            sta [out],y
+            iny
+            iny
+            lda [context],y
+            eor [in],y
+            sta [out],y
+            iny
+            iny
+            lda [context],y
+            eor [in],y
+            sta [out],y
+            iny
+            iny
+            lda [context],y
+            eor [in],y
+            sta [out],y
+
+            ldy #14
+incloop:    lda [counter],y
+            xba
+            inc a
+            xba
+            sta [counter],y
+            bne incdone
+            dey
+            dey
+            bpl incloop
+incdone:
+        }
+        in += 16;
+        out += 16;
+    }
+}
+