How to Convert a String to an Md5 Hash in iOS Using Swift

How can I convert a String to an MD5 hash in iOS using Swift?

There are two steps:

1. Create md5 data from a string

2. Covert the md5 data to a hex string

Swift 2.0:

func md5(string string: String) -> String {
    var digest = [UInt8](count: Int(CC_MD5_DIGEST_LENGTH), repeatedValue: 0)
    if let data = string.dataUsingEncoding(NSUTF8StringEncoding) {
        CC_MD5(data.bytes, CC_LONG(data.length), &digest)
    }

    var digestHex = ""
    for index in 0..        digestHex += String(format: "%02x", digest[index])
    }

    return digestHex
}

//Test:
let digest = md5(string:"Hello")
print("digest: \(digest)")

Output:

digest: 8b1a9953c4611296a827abf8c47804d7

Swift 3.0:

func MD5(string: String) -> Data {
    let messageData = string.data(using:.utf8)!
    var digestData = Data(count: Int(CC_MD5_DIGEST_LENGTH))

    _ = digestData.withUnsafeMutableBytes {digestBytes in
        messageData.withUnsafeBytes {messageBytes in
            CC_MD5(messageBytes, CC_LONG(messageData.count), digestBytes)
        }
    }

    return digestData
}

//Test:
let md5Data = MD5(string:"Hello")

let md5Hex =  md5Data.map { String(format: "%02hhx", $0) }.joined()
print("md5Hex: \(md5Hex)")

let md5Base64 = md5Data.base64EncodedString()
print("md5Base64: \(md5Base64)")

Output:

md5Hex: 8b1a9953c4611296a827abf8c47804d7

md5Base64: ixqZU8RhEpaoJ6v4xHgE1w==

Swift 5.0:

import Foundation
import var CommonCrypto.CC_MD5_DIGEST_LENGTH
import func CommonCrypto.CC_MD5
import typealias CommonCrypto.CC_LONG

func MD5(string: String) -> Data {
        let length = Int(CC_MD5_DIGEST_LENGTH)
        let messageData = string.data(using:.utf8)!
        var digestData = Data(count: length)

        _ = digestData.withUnsafeMutableBytes { digestBytes -> UInt8 in
            messageData.withUnsafeBytes { messageBytes -> UInt8 in
                if let messageBytesBaseAddress = messageBytes.baseAddress, let digestBytesBlindMemory = digestBytes.bindMemory(to: UInt8.self).baseAddress {
                    let messageLength = CC_LONG(messageData.count)
                    CC_MD5(messageBytesBaseAddress, messageLength, digestBytesBlindMemory)
                }
                return 0
            }
        }
        return digestData
    }

//Test:
let md5Data = MD5(string:"Hello")

let md5Hex =  md5Data.map { String(format: "%02hhx", $0) }.joined()
print("md5Hex: \(md5Hex)")

let md5Base64 = md5Data.base64EncodedString()
print("md5Base64: \(md5Base64)")

Output:

md5Hex: 8b1a9953c4611296a827abf8c47804d7

md5Base64: ixqZU8RhEpaoJ6v4xHgE1w==

Notes:

#import must be added to a Bridging-Header file

For how to create a Bridging-Header see this SO answer.

In general MD5 should not be used for new work, SHA256 is a current best practice.

Example from deprecated documentation section:

MD2, MD4, MD5, SHA1, SHA224, SHA256, SHA384, SHA512 (Swift 3+)

These functions will hash either String or Data input with one of eight cryptographic hash algorithms.

The name parameter specifies the hash function name as a String

Supported functions are MD2, MD4, MD5, SHA1, SHA224, SHA256, SHA384 and SHA512
a
This example requires Common Crypto

It is necessary to have a bridging header to the project:

#import

Add the Security.framework to the project.

---

---

This function takes a hash name and String to be hashed and returns a Data:

name: A name of a hash function as a String  
string: The String to be hashed  
returns: the hashed result as Data  

func hash(name:String, string:String) -> Data? {
    let data = string.data(using:.utf8)!
    return hash(name:name, data:data)
}

Examples:

let clearString = "clearData0123456"
let clearData   = clearString.data(using:.utf8)!
print("clearString: \(clearString)")
print("clearData: \(clearData as NSData)")

let hashSHA256 = hash(name:"SHA256", string:clearString)
print("hashSHA256: \(hashSHA256! as NSData)")

let hashMD5 = hash(name:"MD5", data:clearData)
print("hashMD5: \(hashMD5! as NSData)")

Output:

clearString: clearData0123456
clearData: <636c6561 72446174 61303132 33343536>

hashSHA256: 
hashMD5: <4df665f7 b94aea69 695b0e7b baf9e9d6>

Get string md5 in Swift 5

Swift 5 version: Use UnsafeRawBufferPointer as type of the closure argument, and bytes.baseAddress to pass address to the Common Crypto function:

import Foundation
import CommonCrypto

extension String {
    var md5: String {
        let data = Data(self.utf8)
        let hash = data.withUnsafeBytes { (bytes: UnsafeRawBufferPointer) -> [UInt8] in
            var hash = [UInt8](repeating: 0, count: Int(CC_MD5_DIGEST_LENGTH))
            CC_MD5(bytes.baseAddress, CC_LONG(data.count), &hash)
            return hash
        }
        return hash.map { String(format: "%02x", $0) }.joined()
    }
}

(Note that the conversion of a string to UTF-8 data cannot fail, there is no need to return an optional.)

CC_MD5 has been deprecated with the iOS 13. Instead, you can use CC_SHA256.

How to get MD5 hash from string in SWIFT and make bridge-header

You need to add a bridging header and add the #import statement to it.

The easiest way to add a bridging header is to add an Objective-C file to the project, you will be aked ig you want to add a bridging header, reply yes. After that you can delete the Objective-C file file that was added.

Example code:

func md5(#string: String) -> NSData {
    var digest = NSMutableData(length: Int(CC_MD5_DIGEST_LENGTH))!
    if let data :NSData = string.dataUsingEncoding(NSUTF8StringEncoding) {
        CC_MD5(data.bytes, CC_LONG(data.length),
            UnsafeMutablePointer(digest.mutableBytes))
    }
    return digest
}

//Test:
let digest = md5(string:"Here is the test string")
println("digest: \(digest)")

Output:

digest: 8f833933 03a151ea 33bf6e3e bbc28594

Here is a more Swift 2.0 version returning an array of UInt8:

func md5(string string: String) -> [UInt8] {
    var digest = [UInt8](count: Int(CC_MD5_DIGEST_LENGTH), repeatedValue: 0)
    if let data = string.dataUsingEncoding(NSUTF8StringEncoding) {
        CC_MD5(data.bytes, CC_LONG(data.length), &digest)
    }

    return digest
}

Get Base64 encoded SHA12 MD5 digest in Swift

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)

---

Related Topics