1 files changed, 55 insertions, 0 deletions
diff --git a/tools/4/source/src/aes_omac.cpp b/tools/4/source/src/aes_omac.cpp
new file mode 100644
index 0000000..eb6982a
--- /dev/null
+++ b/tools/4/source/src/aes_omac.cpp
@@ -0,0 +1,55 @@
+#include "types.h"
+#include "aes.h"
+
+void _gf_mul(unsigned char *pad)
+{
+	unsigned int i;
+	unsigned cxor = (pad[0] & 0x80) ? 0x87 : 0;
+
+	for(i = 0; i < 15; i++)
+		pad[i] = (pad[i] << 1) | (pad[i + 1] >> 7);
+	pad[15] = (pad[15] << 1) ^ cxor;
+}
+
+void aes_omac1(u8 *digest, u8 *input, u32 length, u8 *key, u32 keybits)
+{
+	u32 i, j;
+	u32 overflow;
+	aes_context ctxt;
+	unsigned char buffer1[16], buffer2[16], dbuf[16];
+
+	memset(buffer1, 0, 16);
+
+	aes_setkey_enc(&ctxt, key, keybits);
+
+	aes_crypt_ecb(&ctxt, AES_ENCRYPT, buffer1, buffer2);
+	_gf_mul(buffer2);
+
+	if(length > 16)
+	{
+		for(i = 0; i < length - 16; i += 16)
+		{
+			for(j = 0; j < 16; j++)
+				dbuf[j] = buffer1[j] ^ input[i + j];
+			aes_crypt_ecb(&ctxt, AES_ENCRYPT, dbuf, buffer1);
+		}
+	}
+
+	overflow = length & 0xf;
+	if(length % 16 == 0)
+		overflow = 16;
+
+	memset(dbuf, 0, 16);
+	memcpy(dbuf, &(input[i]), overflow);
+
+	if(overflow != 16)
+	{
+		dbuf[overflow] = 0x80;
+		_gf_mul(buffer2);
+	}
+
+	for(i = 0; i < 16; i++)
+		dbuf[i] ^= buffer1[i] ^ buffer2[i];
+
+	aes_crypt_ecb(&ctxt, AES_ENCRYPT, dbuf, digest);
+}