ios - tutorial - swift 4.2 commoncrypto




Importing CommonCrypto in a Swift framework (11)

How do you import CommonCrypto in a Swift framework for iOS?

I understand how to use CommonCrypto in a Swift app: You add #import <CommonCrypto/CommonCrypto.h> to the bridging header. However, Swift frameworks don't support bridging headers. The documentation says:

You can import external frameworks that have a pure Objective-C codebase, a pure Swift codebase, or a mixed-language codebase. The process for importing an external framework is the same whether the framework is written in a single language or contains files from both languages. When you import an external framework, make sure the Defines Module build setting for the framework you’re importing is set to Yes.

You can import a framework into any Swift file within a different target using the following syntax:

import FrameworkName

Unfortunately, import CommonCrypto doesn't work. Neither does adding #import <CommonCrypto/CommonCrypto.h> to the umbrella header.


@mogstad has been kind enough to wrap @stephencelis solution in a Cocoapod:

pod 'libCommonCrypto'

The other pods available did not work for me.


For anyone using swift 4.2 with Xcode 10 :

CommonCrypto module is now provided by the system, so you can directly import it like any other system framework.

import CommonCrypto

I found a GitHub project that successfully uses CommonCrypto in a Swift framework: SHA256-Swift . Also, this article about the same problem with sqlite3 was useful.

Based on the above, the steps are:

1) Create a CommonCrypto directory inside the project directory. Within, create a module.map file. The module map will allow us to use the CommonCrypto library as a module within Swift. Its contents are:

module CommonCrypto [system] {
    header "/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator8.0.sdk/usr/include/CommonCrypto/CommonCrypto.h"
    link "CommonCrypto"
    export *
}

2) In Build Settings, within Swift Compiler - Search Paths , add the CommonCrypto directory to Import Paths ( SWIFT_INCLUDE_PATHS ).

3) Finally, import CommonCrypto inside your Swift files as any other modules. For example:

import CommonCrypto

extension String {

    func hnk_MD5String() -> String {
        if let data = self.dataUsingEncoding(NSUTF8StringEncoding)
        {
            let result = NSMutableData(length: Int(CC_MD5_DIGEST_LENGTH))
            let resultBytes = UnsafeMutablePointer<CUnsignedChar>(result.mutableBytes)
            CC_MD5(data.bytes, CC_LONG(data.length), resultBytes)
            let resultEnumerator = UnsafeBufferPointer<CUnsignedChar>(start: resultBytes, length: result.length)
            let MD5 = NSMutableString()
            for c in resultEnumerator {
                MD5.appendFormat("%02x", c)
            }
            return MD5
        }
        return ""
    }
}

Limitations

Using the custom framework in another project fails at compile time with the error missing required module 'CommonCrypto' . This is because the CommonCrypto module does not appear to be included with the custom framework. A workaround is to repeat step 2 (setting Import Paths ) in the project that uses the framework.

The module map is not platform independent (it currently points to a specific platform, the iOS 8 Simulator). I don't know how to make the header path relative to the current platform.

Updates for iOS 8 <= We should remove the line link "CommonCrypto" , to get the successful compilation.

UPDATE / EDIT

I kept getting the following build error:

ld: library not found for -lCommonCrypto for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation)

Unless I removed the line link "CommonCrypto" from the module.map file I created. Once I removed this line it built ok.


I know this is an old question. But I figure out an alternative way to use the library in Swift project, which might be helpful for those who don't want to import framework introduced in these answers.

In Swift project, create a Objective-C bridging header, create NSData category (or custom class that to use the library) in Objective-C. The only drawback would be that you have to write all implementation code in Objective-C. For example:

#import "NSData+NSDataEncryptionExtension.h"
#import <CommonCrypto/CommonCryptor.h>

@implementation NSData (NSDataEncryptionExtension)
- (NSData *)AES256EncryptWithKey:(NSString *)key {
    //do something
}

- (NSData *)AES256DecryptWithKey:(NSString *)key {
//do something
}

And then in your objective-c bridging header, add this

#import "NSData+NSDataEncryptionExtension.h"

And then in Swift class do similar thing:

public extension String {
func encryp(withKey key:String) -> String? {
    if let data = self.data(using: .utf8), let encrypedData = NSData(data: data).aes256Encrypt(withKey: key) {
        return encrypedData.base64EncodedString()
    }
    return nil
}
func decryp(withKey key:String) -> String? {
    if let data = NSData(base64Encoded: self, options: []), let decrypedData = data.aes256Decrypt(withKey: key) {
        return decrypedData.UTF8String
    }
    return nil
}
}

It works as expected.


I'm not sure if something's changed with Xcode 9.2 but it's now much simpler to achieve this. The only things I had to do are create a folder called "CommonCrypto" in my framework project directory and create two files inside it, one called "cc.h" as follows:

#include <CommonCrypto/CommonCrypto.h>
#include <CommonCrypto/CommonRandom.h>

And another called module.modulemap:

module CommonCrypto {
    export *
    header "cc.h"
}

(I don't know why you can't reference header files from the SDKROOT area directly in a modulemap file but I couldn't get it to work)

The third thing is to find the "Import Paths" setting and set to $(SRCROOT). In fact you can set it to whatever folder you want the CommonCrypto folder to be under, if you don't want it at the root level.

After this you should be able to use

import CommonCrypto

In any swift file and all the types/functions/etc. are available.

A word of warning though - if your app uses libCommonCrypto (or libcoreCrypto) it's exceptionally easy for a not-too-sophisticated hacker to attach a debugger to your app and find out what keys are being passed to these functions.


I've added some cocoapods magic to jjrscott's answer in case you need to use CommonCrypto in your cocoapods library.

1) Add this line to your podspec:

s.script_phase = { :name => 'CommonCrypto', :script => 'sh $PROJECT_DIR/../../install_common_crypto.sh', :execution_position => :before_compile }

2) Save this in your library folder or wherever you like (however don't forget to change the script_phase accordingly ...)

# This if-statement means we'll only run the main script if the
# CommonCrypto.framework directory doesn't exist because otherwise
# the rest of the script causes a full recompile for anything
# where CommonCrypto is a dependency
# Do a "Clean Build Folder" to remove this directory and trigger
# the rest of the script to run
FRAMEWORK_DIR="${BUILT_PRODUCTS_DIR}/CommonCrypto.framework"

if [ -d "${FRAMEWORK_DIR}" ]; then
echo "${FRAMEWORK_DIR} already exists, so skipping the rest of the script."
exit 0
fi

mkdir -p "${FRAMEWORK_DIR}/Modules"
echo "module CommonCrypto [system] {
    header "${SDKROOT}/usr/include/CommonCrypto/CommonCrypto.h"
    export *
}" >> "${FRAMEWORK_DIR}/Modules/module.modulemap"

ln -sf "${SDKROOT}/usr/include/CommonCrypto" "${FRAMEWORK_DIR}/Headers"

Works like a charm :)


It happened the same to me after updating Xcode. I tried everything I can do such as reinstalling cocoapods and cleaning the project, but it didn't work. Now it's been solved after restart the system.


It's very simple. Add

#import <CommonCrypto/CommonCrypto.h>

to a .h file (the bridging header file of your project). As a convention you can call it YourProjectName-Bridging-Header.h.

Then go to your project Build Settings and look for Swift Compiler - Code Generation. Under it, add the name of your bridging header to the entry "Objetive-C Bridging Header".

You're done. No imports required in your Swift code. Any public Objective-C headers listed in this bridging header file will be visible to Swift.


The modulemap solutions can be good, and are robust against SDK changes, but I've found them awkward to use in practice, and not as reliable as I'd like when handing things out to others. To try to make it all more foolproof, I went a different way:

Just copy the headers.

I know, fragile. But Apple almost never makes significant changes to CommonCrypto and I'm living the dream that they will not change it in any significant way without also finally making CommonCrypto a modular header.

By "copy the headers" I mean "cut and paste all of the headers you need into one massive header in your project just like the preprocessor would do." As an example of this that you can copy or adapt, see RNCryptor.h .

Note that all of these files are licensed under APSL 2.0, and this approach intentionally maintains the copyright and license notices. My concatenation step is licensed under MIT, and that only applies up to the next license notice).

I am not saying this is a beautiful solution, but so far it seems to have been an incredibly simple solution to both implement and support.


This answer discusses how to make it work inside a framework, and with Cocoapods and Carthage

🐟 modulemap approach

I use modulemap in my wrapper around CommonCrypto https://github.com/onmyway133/arcane , https://github.com/onmyway133/Reindeer

For those getting header not found , please take a look https://github.com/onmyway133/Arcane/issues/4 or run xcode-select --install

  • Make a folder CCommonCrypto containing module.modulemap

      module CCommonCrypto {
        header "/usr/include/CommonCrypto/CommonCrypto.h"
        export *
      }
  • Go to Built Settings -> Import Paths

      ${SRCROOT}/Sources/CCommonCrypto

🌳 Cocoapods with modulemap approach

🐘 public header approach

🐏 Cocoapods with public header approach

🐝 Interesting related posts


WARNING: iTunesConnect may reject apps that are using this method.

New member on my team accidentally broke the solution given by one of the top answers, so I decided to consolidate it in a small wrapper project called CommonCryptoModule . You can install it manually or via Cocoapods:

pod 'CommonCryptoModule', '~> 1.0.2'

Then, all you have to do is to import the module where you need CommonCrypto , like so:

import CommonCryptoModule

Hope someone else finds this useful.





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