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-rw-r--r--src/crypto/aes-eax.c149
1 files changed, 149 insertions, 0 deletions
diff --git a/src/crypto/aes-eax.c b/src/crypto/aes-eax.c
new file mode 100644
index 0000000..3fd6220
--- /dev/null
+++ b/src/crypto/aes-eax.c
@@ -0,0 +1,149 @@
+/*
+ * AES-128 EAX
+ *
+ * Copyright (c) 2003-2007, Jouni Malinen <j@w1.fi>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Alternatively, this software may be distributed under the terms of BSD
+ * license.
+ *
+ * See README and COPYING for more details.
+ */
+
+#include "includes.h"
+
+#include "common.h"
+#include "aes_i.h"
+#include "aes_wrap.h"
+
+/**
+ * aes_128_eax_encrypt - AES-128 EAX mode encryption
+ * @key: Key for encryption (16 bytes)
+ * @nonce: Nonce for counter mode
+ * @nonce_len: Nonce length in bytes
+ * @hdr: Header data to be authenticity protected
+ * @hdr_len: Length of the header data bytes
+ * @data: Data to encrypt in-place
+ * @data_len: Length of data in bytes
+ * @tag: 16-byte tag value
+ * Returns: 0 on success, -1 on failure
+ */
+int aes_128_eax_encrypt(const u8 *key, const u8 *nonce, size_t nonce_len,
+ const u8 *hdr, size_t hdr_len,
+ u8 *data, size_t data_len, u8 *tag)
+{
+ u8 *buf;
+ size_t buf_len;
+ u8 nonce_mac[BLOCK_SIZE], hdr_mac[BLOCK_SIZE], data_mac[BLOCK_SIZE];
+ int i, ret = -1;
+
+ if (nonce_len > data_len)
+ buf_len = nonce_len;
+ else
+ buf_len = data_len;
+ if (hdr_len > buf_len)
+ buf_len = hdr_len;
+ buf_len += 16;
+
+ buf = os_malloc(buf_len);
+ if (buf == NULL)
+ return -1;
+
+ os_memset(buf, 0, 15);
+
+ buf[15] = 0;
+ os_memcpy(buf + 16, nonce, nonce_len);
+ if (omac1_aes_128(key, buf, 16 + nonce_len, nonce_mac))
+ goto fail;
+
+ buf[15] = 1;
+ os_memcpy(buf + 16, hdr, hdr_len);
+ if (omac1_aes_128(key, buf, 16 + hdr_len, hdr_mac))
+ goto fail;
+
+ if (aes_128_ctr_encrypt(key, nonce_mac, data, data_len))
+ goto fail;
+ buf[15] = 2;
+ os_memcpy(buf + 16, data, data_len);
+ if (omac1_aes_128(key, buf, 16 + data_len, data_mac))
+ goto fail;
+
+ for (i = 0; i < BLOCK_SIZE; i++)
+ tag[i] = nonce_mac[i] ^ data_mac[i] ^ hdr_mac[i];
+
+ ret = 0;
+fail:
+ os_free(buf);
+
+ return ret;
+}
+
+
+/**
+ * aes_128_eax_decrypt - AES-128 EAX mode decryption
+ * @key: Key for decryption (16 bytes)
+ * @nonce: Nonce for counter mode
+ * @nonce_len: Nonce length in bytes
+ * @hdr: Header data to be authenticity protected
+ * @hdr_len: Length of the header data bytes
+ * @data: Data to encrypt in-place
+ * @data_len: Length of data in bytes
+ * @tag: 16-byte tag value
+ * Returns: 0 on success, -1 on failure, -2 if tag does not match
+ */
+int aes_128_eax_decrypt(const u8 *key, const u8 *nonce, size_t nonce_len,
+ const u8 *hdr, size_t hdr_len,
+ u8 *data, size_t data_len, const u8 *tag)
+{
+ u8 *buf;
+ size_t buf_len;
+ u8 nonce_mac[BLOCK_SIZE], hdr_mac[BLOCK_SIZE], data_mac[BLOCK_SIZE];
+ int i;
+
+ if (nonce_len > data_len)
+ buf_len = nonce_len;
+ else
+ buf_len = data_len;
+ if (hdr_len > buf_len)
+ buf_len = hdr_len;
+ buf_len += 16;
+
+ buf = os_malloc(buf_len);
+ if (buf == NULL)
+ return -1;
+
+ os_memset(buf, 0, 15);
+
+ buf[15] = 0;
+ os_memcpy(buf + 16, nonce, nonce_len);
+ if (omac1_aes_128(key, buf, 16 + nonce_len, nonce_mac)) {
+ os_free(buf);
+ return -1;
+ }
+
+ buf[15] = 1;
+ os_memcpy(buf + 16, hdr, hdr_len);
+ if (omac1_aes_128(key, buf, 16 + hdr_len, hdr_mac)) {
+ os_free(buf);
+ return -1;
+ }
+
+ buf[15] = 2;
+ os_memcpy(buf + 16, data, data_len);
+ if (omac1_aes_128(key, buf, 16 + data_len, data_mac)) {
+ os_free(buf);
+ return -1;
+ }
+
+ os_free(buf);
+
+ for (i = 0; i < BLOCK_SIZE; i++) {
+ if (tag[i] != (nonce_mac[i] ^ data_mac[i] ^ hdr_mac[i]))
+ return -2;
+ }
+
+ return aes_128_ctr_encrypt(key, nonce_mac, data, data_len);
+}