Merge pull request #546 from anhu/aes_modes_direct_keywrap

AES modes extravaganza. direct and keywrap

Author: JacobBarthelmeh

crypto/aes-modes/aes-direct.c

@@ -0,0 +1,291 @@
+/* aes-direct.c
+ *
+ * Copyright (C) 2006-2025 wolfSSL Inc.
+ *
+ * This file is part of wolfSSL.
+ *
+ * wolfSSL is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * wolfSSL is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
+ */
+
+/* AES-DIRECT Example
+ * This example demonstrates:
+ * - One-shot encryption using wc_AesEncryptDirect() (single block)
+ * - One-shot decryption using wc_AesDecryptDirect() (single block)
+ * Note: DIRECT mode operates on single 16-byte blocks only
+ *       No streaming API available - this is raw block cipher access
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifndef WOLFSSL_USER_SETTINGS
+    #include <wolfssl/options.h>
+#endif
+#include <wolfssl/wolfcrypt/settings.h>
+#include <wolfssl/wolfcrypt/aes.h>
+#include <wolfssl/wolfcrypt/error-crypt.h>
+
+#if !defined(NO_AES) && defined(WOLFSSL_AES_DIRECT)
+
+#define AES_KEY_SIZE    AES_256_KEY_SIZE
+
+static int read_file(const char* filename, byte** data, word32* dataSz)
+{
+    FILE* fp;
+    long fileSz;
+
+    fp = fopen(filename, "rb");
+    if (fp == NULL) {
+        printf("Error: Cannot open file %s\n", filename);
+        return -1;
+    }
+
+    fseek(fp, 0, SEEK_END);
+    fileSz = ftell(fp);
+    fseek(fp, 0, SEEK_SET);
+
+    *data = (byte*)malloc(fileSz);
+    if (*data == NULL) {
+        fclose(fp);
+        printf("Error: Memory allocation failed\n");
+        return -1;
+    }
+
+    *dataSz = (word32)fread(*data, 1, fileSz, fp);
+    fclose(fp);
+
+    return 0;
+}
+
+static int write_file(const char* filename, const byte* data, word32 dataSz)
+{
+    FILE* fp;
+
+    fp = fopen(filename, "wb");
+    if (fp == NULL) {
+        printf("Error: Cannot create file %s\n", filename);
+        return -1;
+    }
+
+    fwrite(data, 1, dataSz, fp);
+    fclose(fp);
+
+    return 0;
+}
+
+/* One-shot encryption using direct block cipher */
+static int encrypt_file(const char* inFile, const char* outFile,
+                        const byte* key, word32 keySz)
+{
+    Aes    aes;
+    byte*  plaintext = NULL;
+    byte*  ciphertext = NULL;
+    word32 plaintextSz;
+    word32 paddedSz;
+    word32 padLen;
+    word32 i;
+    int    ret;
+
+    ret = read_file(inFile, &plaintext, &plaintextSz);
+    if (ret != 0) return ret;
+
+    /* Calculate padded size (PKCS#7 padding) */
+    padLen = AES_BLOCK_SIZE - (plaintextSz % AES_BLOCK_SIZE);
+    paddedSz = plaintextSz + padLen;
+
+    /* Store original size at beginning (4 bytes) + ciphertext */
+    ciphertext = (byte*)malloc(4 + paddedSz);
+    if (ciphertext == NULL) {
+        free(plaintext);
+        return -1;
+    }
+
+    /* Apply PKCS#7 padding */
+    plaintext = (byte*)realloc(plaintext, paddedSz);
+    memset(plaintext + plaintextSz, (int)padLen, padLen);
+
+    /* Initialize AES */
+    ret = wc_AesInit(&aes, NULL, INVALID_DEVID);
+    if (ret != 0) {
+        free(plaintext);
+        free(ciphertext);
+        return ret;
+    }
+
+    ret = wc_AesSetKeyDirect(&aes, key, keySz, NULL, AES_ENCRYPTION);
+    if (ret != 0) {
+        wc_AesFree(&aes);
+        free(plaintext);
+        free(ciphertext);
+        return ret;
+    }
+
+    /* Encrypt block by block using direct API */
+    for (i = 0; i < paddedSz; i += AES_BLOCK_SIZE) {
+        ret = wc_AesEncryptDirect(&aes, ciphertext + 4 + i, plaintext + i);
+        if (ret != 0) {
+            wc_AesFree(&aes);
+            free(plaintext);
+            free(ciphertext);
+            return ret;
+        }
+    }
+
+    wc_AesFree(&aes);
+
+    /* Store original size at beginning */
+    ciphertext[0] = (byte)(plaintextSz >> 24);
+    ciphertext[1] = (byte)(plaintextSz >> 16);
+    ciphertext[2] = (byte)(plaintextSz >> 8);
+    ciphertext[3] = (byte)(plaintextSz);
+
+    ret = write_file(outFile, ciphertext, 4 + paddedSz);
+
+    free(plaintext);
+    free(ciphertext);
+
+    printf("AES-DIRECT encryption complete (one-shot, block by block)\n");
+    return ret;
+}
+
+/* One-shot decryption using direct block cipher */
+static int decrypt_file(const char* inFile, const char* outFile,
+                        const byte* key, word32 keySz)
+{
+    Aes    aes;
+    byte*  ciphertext = NULL;
+    byte*  plaintext = NULL;
+    word32 ciphertextSz;
+    word32 plaintextSz;
+    word32 originalSz;
+    word32 i;
+    int    ret;
+
+    ret = read_file(inFile, &ciphertext, &ciphertextSz);
+    if (ret != 0) return ret;
+
+    if (ciphertextSz < 4 + AES_BLOCK_SIZE) {
+        free(ciphertext);
+        printf("Error: File too small\n");
+        return -1;
+    }
+
+    /* Extract original size from beginning */
+    originalSz = ((word32)ciphertext[0] << 24) |
+                 ((word32)ciphertext[1] << 16) |
+                 ((word32)ciphertext[2] << 8) |
+                 ((word32)ciphertext[3]);
+
+    plaintextSz = ciphertextSz - 4;
+    plaintext = (byte*)malloc(plaintextSz);
+    if (plaintext == NULL) {
+        free(ciphertext);
+        return -1;
+    }
+
+    /* Initialize AES */
+    ret = wc_AesInit(&aes, NULL, INVALID_DEVID);
+    if (ret != 0) {
+        free(ciphertext);
+        free(plaintext);
+        return ret;
+    }
+
+    ret = wc_AesSetKeyDirect(&aes, key, keySz, NULL, AES_DECRYPTION);
+    if (ret != 0) {
+        wc_AesFree(&aes);
+        free(ciphertext);
+        free(plaintext);
+        return ret;
+    }
+
+    /* Decrypt block by block using direct API */
+    for (i = 0; i < plaintextSz; i += AES_BLOCK_SIZE) {
+        ret = wc_AesDecryptDirect(&aes, plaintext + i, ciphertext + 4 + i);
+        if (ret != 0) {
+            wc_AesFree(&aes);
+            free(ciphertext);
+            free(plaintext);
+            return ret;
+        }
+    }
+
+    wc_AesFree(&aes);
+
+    /* Use original size to remove padding */
+    ret = write_file(outFile, plaintext, originalSz);
+
+    free(ciphertext);
+    free(plaintext);
+
+    printf("AES-DIRECT decryption complete (one-shot, no streaming API "
+           "available)\n");
+    return ret;
+}
+
+int main(int argc, char** argv)
+{
+    byte key[AES_KEY_SIZE];
+    int  ret;
+
+    if (argc != 3) {
+        printf("Usage: %s <input file> <output file>\n", argv[0]);
+        printf("Encrypts input file, then decrypts to output file\n");
+        printf("Note: DIRECT mode provides raw block cipher access\n");
+        return 1;
+    }
+
+    wolfCrypt_Init();
+
+    /* Use a fixed key for demonstration */
+    memset(key, 0x08, AES_KEY_SIZE);
+
+    /* Encrypt to temporary file */
+    ret = encrypt_file(argv[1], "temp_encrypted.bin", key, AES_KEY_SIZE);
+    if (ret != 0) {
+        printf("Encryption failed: %d\n", ret);
+        wolfCrypt_Cleanup();
+        return 1;
+    }
+
+    /* Decrypt to output file */
+    ret = decrypt_file("temp_encrypted.bin", argv[2], key, AES_KEY_SIZE);
+    if (ret != 0) {
+        printf("Decryption failed: %d\n", ret);
+        wolfCrypt_Cleanup();
+        return 1;
+    }
+
+    /* Clean up temp file */
+    remove("temp_encrypted.bin");
+
+    printf("Success! Decrypted file written to %s\n", argv[2]);
+
+    wolfCrypt_Cleanup();
+    return 0;
+}
+
+#else
+
+int main(int argc, char** argv)
+{
+    (void)argc;
+    (void)argv;
+    printf("AES-DIRECT not compiled in. Enable with WOLFSSL_AES_DIRECT\n");
+    return 0;
+}
+
+#endif