20161121

CommonCrypto加密解密参数说明

CCCryptorStatus CCCrypt(
    CCOperation op,         /* kCCEncrypt, etc. */
    CCAlgorithm alg,        /* kCCAlgorithmAES128, etc. */
    CCOptions options,      /* kCCOptionPKCS7Padding, etc. */
    const void *key,
    size_t keyLength,
    const void *iv,         /* optional initialization vector */
    const void *dataIn,     /* optional per op and alg */
    size_t dataInLength,
    void *dataOut,          /* data RETURNED here */
    size_t dataOutAvailable,
    size_t *dataOutMoved)
__OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);

参数说明

• CCOperation op加密kCCEncrypt还是解密kCCDecrypt

• CCAlgorithm alg加密算法，枚举如下^[1]

enum {
    kCCAlgorithmAES128 = 0,
    kCCAlgorithmAES = 0,
    kCCAlgorithmDES,
    kCCAlgorithm3DES,       
    kCCAlgorithmCAST,       
    kCCAlgorithmRC4,
    kCCAlgorithmRC2,   
    kCCAlgorithmBlowfish    
};
typedef uint32_t CCAlgorithm;

• CCOptions options可以使用|符号，枚举如下

enum {
    /* options for block ciphers */
    kCCOptionPKCS7Padding   = 0x0001,
    kCCOptionECBMode        = 0x0002
    /* stream ciphers currently have no options */
};
typedef uint32_t CCOptions;

• const void *key加密或解密的钥匙^[2]
• size_t keyLength钥匙的内存长度，请根据加密算法从以下枚举中选择

enum {
    kCCKeySizeAES128          = 16,
    kCCKeySizeAES192          = 24,
    kCCKeySizeAES256          = 32,
    kCCKeySizeDES             = 8,
    kCCKeySize3DES            = 24,
    kCCKeySizeMinCAST         = 5,
    kCCKeySizeMaxCAST         = 16,
    kCCKeySizeMinRC4          = 1,
    kCCKeySizeMaxRC4          = 512,
    kCCKeySizeMinRC2          = 1,
    kCCKeySizeMaxRC2          = 128,
    kCCKeySizeMinBlowfish     = 8,
    kCCKeySizeMaxBlowfish     = 56,
};

• const void *iv初始化矢量，传NULL即可
• const void *dataIn需要加密的数据^[3]
• size_t dataInLength加密数据的内存长度^[4]
• void *dataOut数据输出的地址
• size_t dataOutAvailable为数据输出预留的内存大小
• size_t *dataOutMoved输出的位移

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1. 注意加密和解密时算法要一致 ↩

2. 请注意类型转化成C类型，笔者使用 UTF8String ↩

3. 请注意类型转化成C类型，笔者使用 bytes ↩

4. 内存长度的计算与数据类型有关，请自行百度，这里不做说明 ↩