android – 相当于ios的spongycastle加密

这让我很难过 – 以下代码使用spongycastle的Android加密/解密 – 我正在尝试为iOS实现跨平台加密/解密.

下面的代码(来自Android)使用PKCS7Padding处理AES 128bit CBC,使用提供的salt和密码,salt存储在MysqL 数据库中,密码由最终用户提供,以下代码改编自此回答kelhoer.

我之所以使用AES128bit是因为AES256在iOS 4中不可用,它是在iOS5中引入的,并且不得不使用openssl来生成派生密钥和初始化向量(iv),因为学到苹果拒绝它是很冒险的与openssl库静态链接的应用程序.

由于该平台基于iOS 4.2,使用bundling and statically linking the openssl库似乎相当,过度杀死并且最好使用CommonCryptor库.

这是使用spongycastle 代码的Android版本：

private static void encrypt(InputStream fin,OutputStream fout,String password,byte[] bSalt) {
    try {
        PKCS12ParametersGenerator pGen = new PKCS12ParametersGenerator(
            new SHA256Digest()
            );
        char[] passwordChars = password.tochararray();
        final byte[] pkcs12PasswordBytes = 
            PBEParametersGenerator.PKCS12PasswordToBytes(passwordChars);
        pGen.init(pkcs12PasswordBytes,bSalt,IteraTIONS);
        CBCBlockCipher aesCBC = new CBCBlockCipher(new AESEngine());
        ParametersWithIV aesCBCParams = 
            (ParametersWithIV) pGen.generateDerivedParameters(128,128);
        aesCBC.init(true,aesCBCParams);
        PaddedBufferedBlockCipher aesCipher = 
            new PaddedBufferedBlockCipher(aesCBC,new PKCS7Padding());
        aesCipher.init(true,aesCBCParams);
        byte[] buf = new byte[BUF_SIZE];
        // Read in the decrypted bytes and write the cleartext to out
        int numRead = 0;
        while ((numRead = fin.read(buf)) >= 0) {
            if (numRead == 1024) {
                byte[] plainTemp = new byte[
                    aesCipher.getUpdateOutputSize(numRead)];
                int offset = 
                    aesCipher.processBytes(buf,numRead,plainTemp,0);
                final byte[] plain = new byte[offset];
                System.arraycopy(plainTemp,plain,plain.length);
                fout.write(plain,plain.length);
            } else {
                byte[] plainTemp = new byte[aesCipher.getoutputSize(numRead)];
                int offset = 
                    aesCipher.processBytes(buf,0);
                int last = aesCipher.doFinal(plainTemp,offset);
                final byte[] plain = new byte[offset + last];
                System.arraycopy(plainTemp,plain.length);
            }
        }
        fout.close();
        fin.close();
    } catch (Exception e) {
        e.printstacktrace();
    }

}

private static void decrypt(InputStream fin,128);
        aesCBC.init(false,new PKCS7Padding());
        aesCipher.init(false,0);
                // int last = aesCipher.doFinal(plainTemp,offset);
                final byte[] plain = new byte[offset];
                System.arraycopy(plainTemp,plain.length);
            } else {
                byte[] plainTemp = new byte[
                    aesCipher.getoutputSize(numRead)];
                int offset = 
                    aesCipher.processBytes(buf,plain.length);
            }
        }
        fout.close();
        fin.close();
    } catch (Exception e) {
        e.printstacktrace();
    }
}

但是在iOS 4.2(使用XCode)下我无法弄清楚如何做等效的,

这就是我在Objective C下尝试过的,其目标是解密来自Android端的数据,存储在MysqL 数据库中,以测试它：

+(NSData*) decrypt:(NSData*)cipherData 
    userPassword:(Nsstring*)argPassword 
    genSalt:(NSData*)argPtrSalt{

    size_t szPlainBufLen = cipherData.length + (kCCBlockSizeAES128);
    uint8_t *ptrPlainBuf = malloc(szPlainBufLen);
    //
    const unsigned char *ptrPasswd = 
        (const unsigned char*)[argPassword 
            cStringUsingEncoding:NSASCIIStringEncoding];
    int ptrPasswdLen = strlen(ptrPasswd);
    //
    Nsstring *ptrSaltStr = [[Nsstring alloc]
        initWithData:argPtrSalt 
        encoding:NSASCIIStringEncoding];

    const unsigned char *ptrSalt = 
        (const unsigned char *)[ptrSaltStr UTF8String];
    Nsstring *ptrCipherStr = 
        [[Nsstring alloc]initWithData:cipherData 
            encoding:NSASCIIStringEncoding];
    unsigned char *ptrCipher = (unsigned char *)[ptrCipherStr UTF8String];
    unsigned char key[kCCKeySizeAES128];
    unsigned char iv[kCCKeySizeAES128];
    //
    //int     EVP_BytesToKey(const EVP_CIPHER *type,const EVP_MD *md,//const unsigned char *salt,const unsigned char *data,//int datal,int count,unsigned char *key,unsigned char *iv);
    int i = EVP_BytesToKey(EVP_aes_128_cbc(),EVP_sha256(),ptrSalt,ptrPasswd,ptrPasswdLen,PBKDF2_IteraTIONS,key,iv);
    NSAssert(i == kCCKeySizeAES128,@"Unable to generate key for AES");
    //
    size_t cipherLen = [cipherData length];
    size_t outlength = 0;
    //
    CCCryptorStatus resultCCStatus = CCCrypt(kCCDecrypt,kCCAlgorithmAES128,kCcoptionPKCS7Padding,kCCBlockSizeAES128,iv,ptrCipher,cipherLen,ptrPlainBuf,szPlainBufLen,&outlength);
    NSAssert(resultCCStatus == kCCSuccess,@"Unable to perform PBE AES128bit decryption: %d",errno);
    NSData *ns_dta_PlainData = nil;

    if (resultCCStatus == kCCSuccess){
        ns_dta_PlainData = 
        [NSData dataWithBytesNocopy:ptrPlainBuf length:outlength];
    }else{
        return nil;
    }
    return ns_dta_PlainData;
}

提供了数据和用户密码,并从CCCrypt获得返回码为-4304,表示解码不成功和错误.

我原以为编码方案可能会抛弃CommonCryptor的解密路由,因此转换为NSASCIIStringEncoding的方法很冗长.

Salt与密码数据一起存储,长度为32字节.

考虑到密码学方面的问题,我在这方面缺少什么.

最佳答案

我已经冒昧地编写了Android端口上使用的PKCS12Parameters generator的直接端口,这个标题的要点就在上面.

实现也是直接复制,如发现here,密码,转换为PKCS12等效 – unicode,big-endian,最后填充两个额外的零.

Generator通过执行迭代次数生成派生密钥,在本例中为1000,如在Android端,使用SHA256摘要,最终生成的密钥和iv然后用作CCCryptorCreate的参数.

使用以下代码示例也不起作用,它在调用CCCryptorFinal时以-4304结束

代码摘录如下所示：

#define IteraTIONS 1000

PKCS12ParametersGenerator *pGen = [[PKCS12ParametersGenerator alloc]
        init:argPassword 
        saltedHash:argPtrSalt 
        iterCount:IteraTIONS 
        keySize:128 
        initVectSize:128]; 
//
[pGen generateDerivedParameters];
//
CCCryptorRef decryptor = NULL;
// Create and Initialize the crypto reference.
CCCryptorStatus ccStatus = CCCryptorCreate(kCCDecrypt,pGen.derivedKey.bytes,kCCKeySizeAES128,pGen.derivedIV.bytes,&decryptor
                           );
NSAssert(ccStatus == kCCSuccess,@"Unable to initialise decryptor!");
//
size_t szPlainBufLen = cipherData.length + (kCCBlockSizeAES128);

// Calculate byte block alignment for all calls through to and including final.
size_t szPtrPlainBufSize = CCCryptorGetoutputLength(decryptor,true);
uint8_t *ptrPlainBuf = calloc(szPtrPlainBufSize,sizeof(uint8_t));
//
// Set up initial size.
size_t remainingBytes = szPtrPlainBufSize;
uint8_t *ptr = ptrPlainBuf;
size_t movedBytes = 0;
size_t totalBytesWritten = 0;

// Actually perform the encryption or decryption.
ccStatus = CCCryptorUpdate(decryptor,(const void *) cipherData.bytes,szPtrPlainBufSize,ptr,remainingBytes,&movedBytes
                           );
NSAssert(ccStatus == kCCSuccess,@"Unable to update decryptor! Error: %d",ccStatus);
ptr += movedBytes;
remainingBytes -= movedBytes;
totalBytesWritten += movedBytes;
//
// Finalize everything to the output buffer.
CCCryptorStatus resultCCStatus = CCCryptorFinal(decryptor,&movedBytes
                          );

totalBytesWritten += movedBytes;

if(decryptor) {
    (void) CCCryptorRelease(decryptor);
    decryptor = NULL;
}

NSAssert(resultCCStatus == kCCSuccess,resultCCStatus);

有趣的是,解密工作,对CCCryptorFinal的最后调用返回0,如果我在CCCryptorCreate的开头用kCcoptionPKCS7Padding代替0x0000,即没有填充.唉,这些数据并不是我所期望的,无论什么时候“不起作用”,它仍然是完全混乱的.

它在某个地方失败了,所以如果有人对如何实现等价物有任何更好的想法,我会很高兴听到其他意见.

要么改变Android方面的机制,使其与iPhone“跨平台”兼容,要么寻求替代的加密解决方案,在两端兼容,代价是用于使数据交换便携的平台两侧的加密能力较弱.

提供的输入数据：

> Base64编码密码,盐和密码用’：’分隔：tnNhKyJ2vvrUzAmtQV5q9uEwzzAH63sTKtLf4pOQylw =：qTBluA aNeFnEUfkUFUEVgNYrdz7enn5W1n4Q9uBKYmFfJeSCcbsfziErsa4EU9Cz / pO0KE4WE1QdqRcvSXthQ ==
>提供的密码是f00b4r
>最初的字符串是快速的棕色狐狸跳过懒狗并跑开了

android – 相当于ios的spongycastle加密

相关推荐