2023-02-22

一、 Swift AES ECB Padding .pkcs7 加密解密，密钥字节数不够16位补全：

// AES加密
internal func aes_encrypt(_ str:String, _ aes_key:String) -> String{
    //AES ECB Padding pkcs7需要密钥长度16字节倍数，此处为不够16位补全
    var keyBytes = aes_key.bytes
    let letter = 0x00
    let diffByteNum = 16 - keyBytes.count
    if diffByteNum > 0 {
        for _ in 0..<diffByteNum {
            keyBytes.append(UInt8(letter))
        }
    }
    
    var encryptedStr = ""
    do {//  AES encrypt
        let encrypted = try AES(key: keyBytes, blockMode: ECB(), padding: .pkcs7).encrypt(str.bytes);
        let data = Data(base64Encoded: Data(encrypted), options: .ignoreUnknownCharacters)
        //加密结果从data转成string 转换失败  返回""
        encryptedStr = String(bytes: data!.bytes, encoding: .utf8) ?? ""
    } catch {
        print(error.localizedDescription)
    }
    return encryptedStr
}

//  AES解密
internal func aes_decrypt(_ str:String , _ aes_key:String) -> String{
    //decode base64
    let data = Data(base64Encoded: str, options: .ignoreUnknownCharacters)!
    
    //AES ECB Padding pkcs7需要密钥长度16字节倍数，此处为不够16位补全
    var keyBytes = aes_key.bytes
    let letter = 0x00
    let diffByteNum = 16 - keyBytes.count
    if diffByteNum > 0 {
        for _ in 0..<diffByteNum {
            keyBytes.append(UInt8(letter))
        }
    }
    
    var decrypted: [UInt8] = []
    do {
        // decode AES
        decrypted = try AES(key: keyBytes, blockMode: ECB(), padding: .pkcs7).decrypt(data.bytes);
    } catch {
        print(error.localizedDescription)
    }
    //解密结果从data转成string 转换失败  返回""
    return String(bytes: Data(decrypted).bytes, encoding: .utf8) ?? ""
}