How to hash NSString with SHA1 in Swift?
Your Objective-C code (using a NSString
category) can be directly translated to Swift
(using a String
extension).
First you have to create a "bridging header" and add
#import <CommonCrypto/CommonCrypto.h>
Then:
extension String {
func sha1() -> String {
let data = self.dataUsingEncoding(NSUTF8StringEncoding)!
var digest = [UInt8](count:Int(CC_SHA1_DIGEST_LENGTH), repeatedValue: 0)
CC_SHA1(data.bytes, CC_LONG(data.length), &digest)
let output = NSMutableString(capacity: Int(CC_SHA1_DIGEST_LENGTH))
for byte in digest {
output.appendFormat("%02x", byte)
}
return output as String
}
}
println("Hello World".sha1())
This can be written slightly shorter and Swifter as
extension String {
func sha1() -> String {
let data = self.dataUsingEncoding(NSUTF8StringEncoding)!
var digest = [UInt8](count:Int(CC_SHA1_DIGEST_LENGTH), repeatedValue: 0)
CC_SHA1(data.bytes, CC_LONG(data.length), &digest)
let hexBytes = map(digest) { String(format: "%02hhx", $0) }
return "".join(hexBytes)
}
}
Update for Swift 2:
extension String {
func sha1() -> String {
let data = self.dataUsingEncoding(NSUTF8StringEncoding)!
var digest = [UInt8](count:Int(CC_SHA1_DIGEST_LENGTH), repeatedValue: 0)
CC_SHA1(data.bytes, CC_LONG(data.length), &digest)
let hexBytes = digest.map { String(format: "%02hhx", $0) }
return hexBytes.joinWithSeparator("")
}
}
To return a Base-64 encoded string instead of a hex encoded string, just replace
let hexBytes = digest.map { String(format: "%02hhx", $0) }
return hexBytes.joinWithSeparator("")
with
return NSData(bytes: digest, length: digest.count).base64EncodedStringWithOptions([])
Update for Swift 3:
extension String {
func sha1() -> String {
let data = self.data(using: String.Encoding.utf8)!
var digest = [UInt8](repeating: 0, count:Int(CC_SHA1_DIGEST_LENGTH))
data.withUnsafeBytes {
_ = CC_SHA1($0, CC_LONG(data.count), &digest)
}
let hexBytes = digest.map { String(format: "%02hhx", $0) }
return hexBytes.joined()
}
}
To return a Base-64 encoded string instead of a hex encoded string, just replace
let hexBytes = digest.map { String(format: "%02hhx", $0) }
return hexBytes.joined()
by
return Data(bytes: digest).base64EncodedString()
Update for Swift 4:
The bridging header file is no longer needed, one can import CommonCrypto
instead:
import CommonCrypto
extension String {
func sha1() -> String {
let data = Data(self.utf8)
var digest = [UInt8](repeating: 0, count:Int(CC_SHA1_DIGEST_LENGTH))
data.withUnsafeBytes {
_ = CC_SHA1($0, CC_LONG(data.count), &digest)
}
let hexBytes = digest.map { String(format: "%02hhx", $0) }
return hexBytes.joined()
}
}
Update for Swift 5:
The Data.withUnsafeBytes()
method now calls the closure with an UnsafeRawBufferPointer
to, and baseAddress
is used to pass the initial address to the C function:
import CommonCrypto
extension String {
func sha1() -> String {
let data = Data(self.utf8)
var digest = [UInt8](repeating: 0, count:Int(CC_SHA1_DIGEST_LENGTH))
data.withUnsafeBytes {
_ = CC_SHA1($0.baseAddress, CC_LONG(data.count), &digest)
}
let hexBytes = digest.map { String(format: "%02hhx", $0) }
return hexBytes.joined()
}
}
With CryptoKit
added in iOS13, we now have native Swift API:
import Foundation
import CryptoKit
// CryptoKit.Digest utils
extension Digest {
var bytes: [UInt8] { Array(makeIterator()) }
var data: Data { Data(bytes) }
var hexStr: String {
bytes.map { String(format: "%02X", $0) }.joined()
}
}
func example() {
guard let data = "hello world".data(using: .utf8) else { return }
let digest = Insecure.SHA1.hash(data: data)
print(digest.data) // 20 bytes
print(digest.hexStr) // 2AAE6C35C94FCFB415DBE95F408B9CE91EE846ED
}