ios ObjectC开发 openssl 实现AES-GCM和AES-ECB加密解密并举例

好的，我来解答你的问题。

首先，需要在项目中添加`OpenSSL`库，可以通过`CocoaPods`进行添加，也可以手动添加。

然后，分别实现`AES-GCM`和`AES-ECB`的加密解密操作：

### AES-GCM加密解密

#import <CommonCrypto/CommonCrypto.h>
#include <openssl/aes.h>
#include <openssl/evp.h>
#include <openssl/rand.h>

#define kGCMNonceSize 12 // 96 bits
#define kGCMTagSize 16 // 128 bits

NSData *AESGCMEncrypt(NSData *key, NSData *nonce, NSData *aad, NSData *plainText, NSError **error) {
    if (nonce.length != kGCMNonceSize) {
        if (error != NULL) {
            *error = [NSError errorWithDomain:@"com.example.AESGCMEncrypt" code:-1 userInfo:@{NSLocalizedDescriptionKey: @"Invalid nonce size"}];
        }
        return nil;
    }

    unsigned char *keyBytes = (unsigned char *)[key bytes];
    unsigned char *nonceBytes = (unsigned char *)[nonce bytes];
    unsigned char *aadBytes = (unsigned char *)[aad bytes];
    unsigned char *plainTextBytes = (unsigned char *)[plainText bytes];

    unsigned char tag[kGCMTagSize];
    memset(tag, 0, kGCMTagSize);

    size_t cipherTextLength = plainText.length + kGCMTagSize;
    unsigned char *cipherTextBytes = malloc(cipherTextLength);
    memset(cipherTextBytes, 0, cipherTextLength);

    unsigned char *cipherTextPtr = cipherTextBytes;
    size_t cipherTextLen = 0;

    EVP_CIPHER_CTX *ctx = EVP_CIPHER_CTX_new();
    EVP_EncryptInit_ex(ctx, EVP_aes_256_gcm(), NULL, NULL, NULL);
    EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_IVLEN, (int)nonce.length, NULL);
    EVP_EncryptInit_ex(ctx, NULL, NULL, keyBytes, nonceBytes);
    EVP_EncryptUpdate(ctx, NULL, (int *)&cipherTextLen, aadBytes, (int)aad.length);
    EVP_EncryptUpdate(ctx, cipherTextPtr, (int *)&cipherTextLen, plainTextBytes, (int)plainText.length);
    EVP_EncryptFinal_ex(ctx, cipherTextPtr+cipherTextLen, (int *)&cipherTextLen);
    EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_GET_TAG, kGCMTagSize, tag);
    EVP_CIPHER_CTX_free(ctx);

    NSMutableData *cipherText = [[NSMutableData alloc] initWithBytes:cipherTextBytes length:cipherTextLen+kGCMTagSize];
    [cipherText appendBytes:tag length:kGCMTagSize];
    free(cipherTextBytes);

    return cipherText;
}

NSData *AESGCMDecrypt(NSData *key, NSData *nonce, NSData *aad, NSData *cipherText, NSError **error) {
    if (nonce.length != kGCMNonceSize) {
        if (error != NULL) {
            *error = [NSError errorWithDomain:@"com.example.AESGCMDecrypt" code:-1 userInfo:@{NSLocalizedDescriptionKey: @"Invalid nonce size"}];
        }
        return nil;
    }

    unsigned char *keyBytes = (unsigned char *)[key bytes];
    unsigned char *nonceBytes = (unsigned char *)[nonce bytes];
    unsigned char *aadBytes = (unsigned char *)[aad bytes];
    unsigned char *cipherTextBytes = (unsigned char *)[cipherText bytes];

    unsigned char tag[kGCMTagSize];
    memcpy(tag, cipherTextBytes+cipherText.length-kGCMTagSize, kGCMTagSize);

    size_t plainTextLength = cipherText.length - kGCMTagSize;
    unsigned char *plainTextBytes = malloc(plainTextLength);
    memset(plainTextBytes, 0, plainTextLength);

    unsigned char *plainTextPtr = plainTextBytes;
    size_t plainTextLen = 0;

    EVP_CIPHER_CTX *ctx = EVP_CIPHER_CTX_new();
    EVP_DecryptInit_ex(ctx, EVP_aes_256_gcm(), NULL, NULL, NULL);
    EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_IVLEN, (int)nonce.length, NULL);
    EVP_DecryptInit_ex(ctx, NULL, NULL, keyBytes, nonceBytes);
    EVP_DecryptUpdate(ctx, NULL, (int *)&plainTextLen, aadBytes, (int)aad.length);
    EVP_DecryptUpdate(ctx, plainTextPtr, (int *)&plainTextLen, cipherTextBytes, (int)plainTextLength);
    EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_TAG, kGCMTagSize, tag);

    int ret = EVP_DecryptFinal_ex(ctx, plainTextPtr+plainTextLen, (int *)&plainTextLen);
    EVP_CIPHER_CTX_free(ctx);

    if (ret <= 0) {
        if (error != NULL) {
            *error = [NSError errorWithDomain:@"com.example.AESGCMDecrypt" code:-1 userInfo:@{NSLocalizedDescriptionKey: @"Decryption failed"}];
        }
        return nil;
    }

    NSData *plainText = [[NSData alloc] initWithBytes:plainTextBytes length:plainTextLen];
    free(plainTextBytes);

    return plainText;
}

使用示例：

NSData *key = [NSData dataWithBytes:"01234567890123456789012345678901" length:32];
NSData *nonce = [NSData dataWithBytes:"012345678901" length:12];
NSData *aad = [@"additional authenticated data" dataUsingEncoding:NSUTF8StringEncoding];
NSData *plainText = [@"plain text" dataUsingEncoding:NSUTF8StringEncoding];

NSError *error = nil;
NSData *cipherText = AESGCMEncrypt(key, nonce, aad, plainText, &error);
if (cipherText != nil) {
    NSData *decryptedPlainText = AESGCMDecrypt(key, nonce, aad, cipherText, &error);
    NSLog(@"Decrypted plain text: %@", [[NSString alloc] initWithData:decryptedPlainText encoding:NSUTF8StringEncoding]);
} else {
    NSLog(@"Encryption failed: %@", error.localizedDescription);
}

### AES-ECB加密解密

NSData *AESECBEncrypt(NSData *key, NSData *plainText) {
    unsigned char *keyBytes = (unsigned char *)[key bytes];
    unsigned char *plainTextBytes = (unsigned char *)[plainText bytes];

    size_t cipherTextLength = plainText.length + AES_BLOCK_SIZE;
    unsigned char *cipherTextBytes = malloc(cipherTextLength);
    memset(cipherTextBytes, 0, cipherTextLength);

    unsigned char *cipherTextPtr = cipherTextBytes;
    size_t cipherTextLen = 0;

    AES_KEY aesKey;
    AES_set_encrypt_key(keyBytes, (int)(key.length*8), &aesKey);
    AES_encrypt(plainTextBytes, cipherTextPtr, &aesKey);

    NSData *cipherText = [[NSData alloc] initWithBytes:cipherTextBytes length:cipherTextLen+AES_BLOCK_SIZE];
    free(cipherTextBytes);

    return cipherText;
}

NSData *AESECBDecrypt(NSData *key, NSData *cipherText) {
    unsigned char *keyBytes = (unsigned char *)[key bytes];
    unsigned char *cipherTextBytes = (unsigned char *)[cipherText bytes];

    size_t plainTextLength = cipherText.length;
    unsigned char *plainTextBytes = malloc(plainTextLength);
    memset(plainTextBytes, 0, plainTextLength);

    unsigned char *plainTextPtr = plainTextBytes;
    size_t plainTextLen = 0;

    AES_KEY aesKey;
    AES_set_decrypt_key(keyBytes, (int)(key.length*8), &aesKey);
    AES_decrypt(cipherTextBytes, plainTextPtr, &aesKey);

    NSData *plainText = [[NSData alloc] initWithBytes:plainTextBytes length:plainTextLen];
    free(plainTextBytes);

    return plainText;
}

使用示例：

NSData *key = [NSData dataWithBytes:"01234567890123456789012345678901" length:32];
NSData *plainText = [@"plain text" dataUsingEncoding:NSUTF8StringEncoding];

NSData *cipherText = AESECBEncrypt(key, plainText);
NSData *decryptedPlainText = AESECBDecrypt(key, cipherText);
NSLog(@"Decrypted plain text: %@", [[NSString alloc] initWithData:decryptedPlainText encoding:NSUTF8StringEncoding]);

注意：`AES-ECB`加密模式不安全，不建议使用。建议使用`AES-GCM`等更加安全的加密模式。