SHA256 快速 [英] SHA256 in swift

问题描述

我想在我的项目中使用 sha256，但是在将 objC 代码重写为 swift 代码时遇到了一些麻烦.请帮帮我.我用了这个答案:如何在 iOS 中计算 SHA-2(最好是 SHA 256 或 SHA 512)哈希?

I want to use sha256 in my project, but I had some troubles rewriting objC code to swift code. Help me please. I used this answer: How can I compute a SHA-2 (ideally SHA 256 or SHA 512) hash in iOS?

这是我的代码

var hash : [CUnsignedChar]
CC_SHA256(data.bytes, data.length, hash)
var res : NSData = NSData.dataWithBytes(hash, length: CC_SHA256_DIGEST_LENGTH)

它给了我错误的一切，因为例如 swift 无法将 Int 转换为 CC_LONG.

it gives me error everything because swift cannot convert Int to CC_LONG, for example.

推荐答案

你必须在 Int 和 CC_LONG 之间显式转换，因为 Swift 没有进行隐式转换，如 (Objective-)C.

You have to convert explicitly between Int and CC_LONG, because Swift does not do implicit conversions, as in (Objective-)C.

您还必须将 hash 定义为所需大小的数组.

You also have to define hash as an array of the required size.

func sha256(data : NSData) -> NSData {
    var hash = [UInt8](count: Int(CC_SHA256_DIGEST_LENGTH), repeatedValue: 0)
    CC_SHA256(data.bytes, CC_LONG(data.length), &hash)
    let res = NSData(bytes: hash, length: Int(CC_SHA256_DIGEST_LENGTH))
    return res
}

或者，您可以使用 NSMutableData 来分配所需的缓冲区:

Alternatively, you can use NSMutableData to allocate the needed buffer:

func sha256(data : NSData) -> NSData {
    let res = NSMutableData(length: Int(CC_SHA256_DIGEST_LENGTH))
    CC_SHA256(data.bytes, CC_LONG(data.length), UnsafeMutablePointer(res.mutableBytes))
    return res
}

Swift 3 和 4 的更新:

func sha256(data : Data) -> Data {
    var hash = [UInt8](repeating: 0,  count: Int(CC_SHA256_DIGEST_LENGTH))
    data.withUnsafeBytes {
        _ = CC_SHA256($0, CC_LONG(data.count), &hash)
    }
    return Data(bytes: hash)
}

Swift 5 更新:

func sha256(data : Data) -> Data {
    var hash = [UInt8](repeating: 0,  count: Int(CC_SHA256_DIGEST_LENGTH))
    data.withUnsafeBytes {
        _ = CC_SHA256($0.baseAddress, CC_LONG(data.count), &hash)
    }
    return Data(hash)
}

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