1 files changed, 47 insertions, 0 deletions
diff --git a/include/aes_omac.h b/include/aes_omac.h
new file mode 100755
index 0000000..06150a4
--- /dev/null
+++ b/include/aes_omac.h
@@ -0,0 +1,47 @@
+// I mean if OpenSSL doesn't include it...
+//  released under GPLv3, see http://gplv3.fsf.org/
+
+void rol1(u8* worthless) {
+  int i;
+  u8 xor = (worthless[0]&0x80)?0x87:0;
+  for(i=0;i<0xF;i++) {
+    worthless[i] <<= 1;
+    worthless[i] |= worthless[i+1]>>7;
+  }
+  worthless[0xF] <<= 1;
+  worthless[0xF] ^= xor;
+}
+
+void aesOmac1Mode(u8* output, u8* input, int len, u8* aes_key_data, int aes_key_bits) {
+  int i,j;
+  AES_KEY aes_key;
+  AES_set_encrypt_key(aes_key_data, aes_key_bits, &aes_key);
+
+  u8 running[0x10]; memset(running, 0, 0x10);
+  u8 hash[0x10];
+  u8 worthless[0x10];
+  u8 final[0x10];
+
+  AES_encrypt(running, worthless, &aes_key);
+  rol1(worthless);
+
+  if(len > 0x10) {
+    for(i=0;i<(len-0x10);i+=0x10) {
+      for(j=0;j<0x10;j++) hash[j] = running[j] ^ input[i+j];
+      AES_encrypt(hash, running, &aes_key);
+    }
+  }
+  int overrun = len&0xF;
+  if( (len%0x10) == 0 ) overrun = 0x10;
+
+  memset(hash, 0, 0x10);
+  memcpy(hash, &input[i], overrun);
+
+  if(overrun != 0x10) {
+    hash[overrun] = 0x80;
+    rol1(worthless);
+  }
+
+  for(j=0;j<0x10;j++) hash[j] ^= running[j] ^ worthless[j];
+  AES_encrypt(hash, output, &aes_key);
+}