CBC 模式下的 AES 加密，随机 IV（Swift 2.3）

iv 以加密数据为前缀

aesCBC128Encrypt 将创建一个随机 IV 并以加密代码为前缀。aesCBC128Decrypt 将在解密期间使用前缀 IV。

输入是数据，键是数据对象。如果需要的编码形式（如 Base64）在调用方法中转换为和/或来自。

密钥应该是 128 位（16 字节）。有关其他键大小，请参阅 Swift 3.0 示例。

PKCS#7 填充默认设置。

此示例需要 Common Crypto 必须为项目提供桥接头：#import <CommonCrypto / CommonCrypto.h>将 Security.framework 添加到项目中。

有关说明，请参阅 Swift 3 示例。

这是示例，而不是生产代码。

func aesCBC128Encrypt(data data:[UInt8], keyData:[UInt8]) -> [UInt8]? {
    let keyLength   = size_t(kCCKeySizeAES128)
    let ivLength    = size_t(kCCBlockSizeAES128)
    let cryptDataLength = size_t(data.count + kCCBlockSizeAES128)
    var cryptData = [UInt8](count:ivLength + cryptDataLength, repeatedValue:0)

    let status = SecRandomCopyBytes(kSecRandomDefault, Int(ivLength), UnsafeMutablePointer<UInt8>(cryptData));
    if (status != 0) {
        print("IV Error, errno: \(status)")
        return nil
    }

    var numBytesEncrypted :size_t = 0
    let cryptStatus = CCCrypt(CCOperation(kCCEncrypt),
                              CCAlgorithm(kCCAlgorithmAES128),
                              CCOptions(kCCOptionPKCS7Padding),
                              keyData, keyLength,
                              cryptData,
                              data, data.count,
                              &cryptData + ivLength, cryptDataLength,
                              &numBytesEncrypted)

    if UInt32(cryptStatus) == UInt32(kCCSuccess) {
        cryptData.removeRange(numBytesEncrypted+ivLength..<cryptData.count)
    }
    else {
        print("Error: \(cryptStatus)")
        return nil;
    }

    return cryptData;
}

func aesCBC128Decrypt(data data:[UInt8], keyData:[UInt8]) -> [UInt8]? {
    let clearLength = size_t(data.count)
    var clearData   = [UInt8](count:clearLength, repeatedValue:0)

    let keyLength   = size_t(kCCKeySizeAES128)
    let ivLength    = size_t(kCCBlockSizeAES128)

    var numBytesDecrypted :size_t = 0
    let cryptStatus = CCCrypt(CCOperation(kCCDecrypt),
                              CCAlgorithm(kCCAlgorithmAES128),
                              CCOptions(kCCOptionPKCS7Padding),
                              keyData, keyLength,
                              data,
                              UnsafePointer<UInt8>(data) + ivLength, data.count - ivLength,
                              &clearData, clearLength,
                              &numBytesDecrypted)

    if UInt32(cryptStatus) == UInt32(kCCSuccess) {
        clearData.removeRange(numBytesDecrypted..<clearLength)

    } else {
        print("Error: \(cryptStatus)")
        return nil;
    }

    return clearData;
}

用法示例：

let clearData = toData("clearData0123456")
let keyData   = toData("keyData890123456")

print("clearData:   \(toHex(clearData))")
print("keyData:     \(toHex(keyData))")
let cryptData = aesCBC128Encrypt(data:clearData, keyData:keyData)!
print("cryptData:   \(toHex(cryptData))")
let decryptData = aesCBC128Decrypt(data:cryptData, keyData:keyData)!
print("decryptData: \(toHex(decryptData))")

示例输出：

clearData:   <636c6561 72446174 61303132 33343536>
keyData:     <6b657944 61746138 39303132 33343536>
cryptData:   <9fce4323 830e3734 93dd93bf e464f72a a653a3a5 2c40d5ea e90c1017 958750a7 ff094c53 6a81b458 b1fbd6d4 1f583298>
decryptData: <636c6561 72446174 61303132 33343536>