MimicSSL-AES128-CBC-DECRYPT

This is an AES-128 CBC implementation in C23 only for decrypting, and its API is compatible with OpenSSL 1.1. See FIPS PUB 197 for the AES specifications.

Note that the current implementation works only on little-endian platforms.

Example

An example usage would be as follows:

int decrypt(FILE *in, FILE *out)
{
    unsigned char inbuf[1024], outbuf[1024];
    int inlen, outlen;
    EVP_CIPHER_CTX *ctx;
    unsigned char key[] = "0123456789abcdeF";
    unsigned char iv[] = "1234567887654321";

    if ((ctx = EVP_CIPHER_CTX_new()) == NULL) {
        return 0;
    }
    if (!EVP_DecryptInit_ex(ctx, EVP_aes_128_cbc(), NULL, key, iv)) {
        EVP_CIPHER_CTX_free(ctx);
        return 0;
    }
    for (;;) {
        inlen = fread(inbuf, 1, 1024, in);
        if (inlen <= 0) {
            break;
        }
        if (!EVP_DecryptUpdate(ctx, outbuf, &outlen, inbuf, inlen)) {
            EVP_CIPHER_CTX_free(ctx);
            return 0;
        }
        fwrite(outbuf, 1, outlen, out);
    }
    if (!EVP_DecryptFinal_ex(ctx, outbuf, &outlen)) {
        EVP_CIPHER_CTX_free(ctx);
        return 0;
    }
    if (outlen > 0) {
        fwrite(outbuf, 1, outlen, out);
    }
    EVP_CIPHER_CTX_free(ctx);
    return 1;
}

Build

This repository uses lighter for testing as a submodule of Git. So clone it as follows:

git clone --recursive URL

Then build the library on macOS or Linux as follows:

cmake -S . -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build
ctest --test-dir build
cmake --install build --prefix=/path/to/dir

Or on Windows as follows:

cmake -S . -B build
cmake --build build --config Release
ctest --test-dir build -C Release
cmake --install build --config Release --prefix=/path/to/dir

Build for Android

Set environment variables ANDROID_HOME and ANDROID_NDK appropriately. For example:

export ANDROID_HOME=/usr/local/lib/android/sdk
export ANDROID_NDK=$ANDROID_HOME/ndk/25.2.9519653

Note that the value of ANDROID_HOME will vary depending on your environment, but a typical configuration would be as follows:

• Windows: C:\\Users\\USERNAME\\AppData\\Local\\Android\\sdk
• Linux: /home/USERNAME/Android/Sdk
• macOS: /Users/USERNAME/Library/Android/sdk

Then build the library as follows:

abi=ABI
build_dir=BUILD_DIR
sh android.sh $build_dir configure $abi -G Ninja \
    -DCMAKE_MAKE_PROGRAM="/path/to/ninja" \
    -DCMAKE_BUILD_TYPE=Release \
    -DCMAKE_INSTALL_PREFIX:PATH="/path/to/dir"
cmake --build $build_dir/$abi -v
cmake --install $build_dir/$abi

ABI should be replaced by arm64-v8a, armeabi-v7a, x86, or x86_64. BUILD_DIR should be replaced by the build directory (e.g., build-android). Note that ninja is required on Windows.

Before running testsuite, start Android Emulator as follows:

$ANDROID_HOME/emulator/emulator -avd AVD_NAME -no-snapshot

AVD_NAME should be replaced by the AVD name. Note that You can get the list of AVD names as follows:

$ANDROID_HOME/emulator/emulator -list-avds

Then run testusite as follows:

sh android.sh $build_dir test $abi

Build for iOS

Build the library on macOS as follows:

build_dir=BUILD_DIR
sh ios.sh $build_dir configure
sh ios.sh $build_dir build --config Release
sh ios.sh $build_dir install /path/to/dir --config Release

BUILD_DIR should be replaced by the build directory (e.g., build-ios).

You can run testsuite with the iPhone simulator as follows:

sh ios.sh $build_dir test ARCH -C Release

ARCH should be replaced by arm64 or x86_64. Note that jq is required to run the iPhone simulator.