Get Base64 encoded SHA12 MD5 digest in Swift

Question

I am trying to convert a string to SHA512 MD5 hash with Bas64 encoding. I tried below code for the same but it is returning wrong string.

func sha512Base64(string: String) -> String {
        let digest = NSMutableData(length: Int(CC_SHA512_DIGEST_LENGTH))!
        if let data = string.data(using: String.Encoding.utf8) {
    
            let value =  data as NSData
            let uint8Pointer = UnsafeMutablePointer<UInt8>.allocate(capacity: digest.length)
            CC_SHA512(value.bytes, CC_LONG(data.count), uint8Pointer)
    
        }
        return digest.base64EncodedString(options: NSData.Base64EncodingOptions([]))
    }

Please suggest me the exact solution or the defects in above method.

Thanks in advance.

Can you provide more details how do you validate an output string or where do you use it? — iUrii, Oct 26 '20 at 15:21

score 2 · Accepted Answer · answered Oct 26 '20 at 16:09

I rewrote your code a little. Try this

func sha512Base64(string: String) -> String? {
    guard let data = string.data(using: String.Encoding.utf8) else {
        return nil
    }

    var digest = Data(count: Int(CC_SHA512_DIGEST_LENGTH))
    _ = digest.withUnsafeMutableBytes { digestBytes -> UInt8 in
        data.withUnsafeBytes { messageBytes -> UInt8 in
            if let mb = messageBytes.baseAddress, let db = digestBytes.bindMemory(to: UInt8.self).baseAddress {
                let length = CC_LONG(data.count)
                CC_SHA512(mb, length, db)
            }
            return 0
        }
    }
    return digest.base64EncodedString()
}

I like this answer https://stackoverflow.com/a/52120827

with his approach you can use it like

"123".hashed(.sha512, output: .base64)

idz · Answer 2 · 2020-10-26T18:15:54.570

In your question title you mention SHA512 and MD5 these are two different things. Since your code appears to try to calculate SHA512, I am going to assume that is what you want.

When you're calling into C functions you can use appropriately typed Swift arrays to save you a lot of headaches. Leveraging this you can rewrite you code as follows:

func sha512Base64(string: String) -> String {
    guard let data = string.data(using: .utf8) else {
        fatalError("Failed to convert string to data")
    }
    var digest = [UInt8](repeating: 0, count: Int(CC_SHA512_DIGEST_LENGTH))
    let dataArray = Array(data)
    CC_SHA512(dataArray, CC_LONG(data.count), &digest)
    return Data(digest).base64EncodedString()
}

I should mention, if you can use Apple's CryptoKit, it's much easier:

import CryptoKit

func sha512Base64(string: String) -> String {
    guard let data = string.data(using: .utf8) else {
        fatalError("Failed to convert string to data")
    }
    let hash = SHA512.hash(data: data)
    return Data(hash).base64EncodedString()
}

CryptoKit is supported from iOS 13.0 onwards.

Get Base64 encoded SHA12 MD5 digest in Swift

2 Answers2