Mihael Isaev Mihael Isaev - 7 months ago 698
Swift Question

How to crypt string to sha1 with Swift?

In objective-c it looks like this:

#include <sys/xattr.h>

@implementation NSString (reverse)

-(NSString*)sha1
{
NSData *data = [self dataUsingEncoding:NSUTF8StringEncoding];
uint8_t digest[CC_SHA1_DIGEST_LENGTH];
CC_SHA1(data.bytes, (int)data.length, digest);
NSMutableString *output = [NSMutableString stringWithCapacity:CC_SHA1_DIGEST_LENGTH * 2];
for (int i = 0; i < CC_SHA1_DIGEST_LENGTH; i++)
[output appendFormat:@"%02x", digest[i]];
return output;
}

@end


I need something like this with Swift, is it possible?

Please, show work example.

Answer

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("")
    }
}
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