PKCS5.PBKDF2 works much slower after v1.0.0

[sche]

Describe the bug

After v1.0.0 the PKCS5.PBKDF2 works much slower. It influences crypto-projects that rely on CryptoSwift.
E.g.
HDWallet: https://github.com/essentiaone/HDWallet/blob/c1c5beb470d52673b89388b09d782345609d78f2/HDWalletKit/Mnemonic/Mnemonic.swift#L51
web3swift: https://github.com/matter-labs/web3swift/blob/e36e767eb2de26decb0c157aeef2d023a1175076/Sources/web3swift/KeystoreManager/BIP39.swift#L152

Both libraries rely at the moment on CryptoSwift v1.0.0

Because of this, provided places in libs generate mnemonic seed several seconds with CryptoSwift v > 1.0.0

I tried to dig into to understand what causes it, and the bottleneck is here:

CryptoSwift/Sources/CryptoSwift/SHA2.swift

Line 184 in af1b58f

for j in 0..<self.k.count {

Benchmarking this loop in v1.0.0 compared to v1.2.0 demonstrates that in v1.0.0 it works much faster.

Here is a unit test to check it:

    func testPBKDF2Performance() {
        let passwordBytesHex = "73686f7020656c656374726963206c616464657220666f727761"
        let saltBytes = "6d6e656d6f6e6968"
        print("Start: \(Date())")
        _ = try! PKCS5.PBKDF2(password: Data(hex: passwordBytesHex).bytes,
                              salt: Data(hex: saltBytes).bytes,
                              iterations: 2048,
                              keyLength: 64,
                              variant: HMAC.Variant.sha512).calculate()
        print("End: \(Date())")
    }

Results for v1.0.0 on my mac with 2,4 GHz 8-Core Intel Core i9:
Start: 2020-10-07 13:11:01 +0000
End: 2020-10-07 13:11:01 +0000

Results for v1.2.0
Start: 2020-10-07 13:16:27 +0000
End: 2020-10-07 13:16:32 +0000

I tied to replace in 1.2.0 completely files SHA2.swift and Utils.swift with version from 1.0.0 but it did not help.

Probably this is an already known issue.

[krzyzanowskim]

Do you test Release build? I didn't notice this regression in performance tests hm.

[sche]

Yes, I tried different release builds.
So it works fine on your side (the example I provided)?

[grillr]

Same here! Version 1.0.0 is way faster than 1.3.2.

[krzyzanowskim]

do you use swift 5.3 on CryptoSwift 1.0? I'm yet to diagnose whether it's compiler or swift code regression

[grillr]

Yes, I use swift 5.3.

[krzyzanowskim]

This makes me think and I run test PBKDFPerf and that's what I see. That is for 65536 iterations

SHA1
v1.0.0 Avg 0.667
v1.3.0 Avg 0.796

SHA256
v1.0.0 Avg 0.445
v1.3.0 Avg 0.510

SHA512
v1.0.0 Avg 0.516
v1.3.0 Avg 0.640

When I run 2048 iterations, as per @sche example, the result is
SHA256
v1.0.0 Avg 0.029
v1.3.0 Avg 0.032

Although there's a difference that is visible in numbers, it's not what I expected to see. If it takes you more than a second, that cany only means you're running unoptimized Swift (aka debug build). What I'm missing here?

My mac is 2,8 GHz Quad-Core Intel Core i7

[sche]

Hi @krzyzanowskim ,
I am testing PBKDF2 when CryptoSwift is imported via CocoaPods or SwiftPM.
I tried to run performance tests in CryptoSwift repo master branch, but I am getting a compilation error:

No 'swiftinterface' files found within '..../Build/Products/Test-iphonesimulator/CryptoSwift.framework/Modules/CryptoSwift.swiftmodule'.
Command PhaseScriptExecution failed with a nonzero exit code

Although there's a difference that is visible in numbers, it's not what I expected to see. If it takes you more than a second, that cany only means you're running unoptimized Swift (aka debug build). What I'm missing here?

It works slow on optimized Swift for me when it is improted as a dependency. But only with versions > 1.0

Could you try to run the same performance test in a setup I described? (importing CryptoSwift with CocoaPods / SwiftPM)
Thanks!

[krzyzanowskim]

I tried to run performance tests in CryptoSwift repo master branch, but I am getting a compilation error:

What is your Podfile, is this master branch or 1.3.2? what Xcode and CocoaPods version. Does Pod target uses Release for sure? There are so many configuration nuances with Cocoapods

(importing CryptoSwift with CocoaPods / SwiftPM)

I created SwiftPM sample package with your test code https://github.com/krzyzanowskim/CryptoSwift/issues/832#issue-716527818
CryptoSwift-sample-test.zip

❯ swift run -c release          
Fetching https://github.com/krzyzanowskim/CryptoSwift.git
Cloning https://github.com/krzyzanowskim/CryptoSwift.git
Resolving https://github.com/krzyzanowskim/CryptoSwift.git at 1.3.2
[3/3] Linking CryptoSwift-sample-test
Duration: 0.020466089248657227 (seconds)

And the same but with Xcode

Duration: 0.020154953002929688 (seconds)

Can you run it and report back result?

[sche]

Hi @krzyzanowskim

What is your Podfile, is this master branch or 1.3.2? what Xcode and CocoaPods version. Does Pod target uses Release for sure? There are so many configuration nuances with Cocoapods

I checked out CryptoSwift master branch, opened CryptoSwift.xcodeproj and tried to run PBKDFPerf tests.
I checked it one more time and it works now (I updated XCode recently and updated master branch, so problem solved here)

Your example on my mac:

% swift run -c release
Fetching https://github.com/krzyzanowskim/CryptoSwift.git
Cloning https://github.com/krzyzanowskim/CryptoSwift.git
Resolving https://github.com/krzyzanowskim/CryptoSwift.git at 1.3.2
[3/3] Linking CryptoSwift-sample-test
Duration: 0.022337913513183594 (seconds)

Here I tried to run same test in iOS app on iPhone 11 (14.1) simulator with CryptoSwift 1.3.2:

Start: 2020-11-06 17:29:53 +0000
End: 2020-11-06 17:29:57 +0000

TestCryptoSwift.zip

But now it is slow even if I try to run it with 1.0.0 version imported via SwiftPM 🤷‍♂️
Importing 1.0.0 via pod (v1.10.0) didn't work for me now... I am getting:

Undefined symbols for architecture x86_64:
  "(extension in CryptoSwift):Foundation.Data.init(hex: Swift.String) -> Foundation.Data", referenced from:
      TestCryptoSwiftPodTests.TestCryptoSwiftPodTests.testPBKDF2Performance() -> () in TestCryptoSwiftPodTests.o
  "(extension in CryptoSwift):Foundation.Data.bytes.getter : [Swift.UInt8]", referenced from:
      TestCryptoSwiftPodTests.TestCryptoSwiftPodTests.testPBKDF2Performance() -> () in TestCryptoSwiftPodTests.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

TestCryptoSwiftPod.zip

But it works if I change version to 1.3.2 (which is still slow)

[krzyzanowskim]

Here I tried to run same test in iOS app on iPhone 11 (14.1) simulator with CryptoSwift 1.3.2:

simulator speed is pretty much your mac speed, are you sure you didn't run debug build there?

Importing 1.0.0 via pod (v1.10.0) didn't work for me now... I am getting:

some cocoapods setup leftovers gets in the way, either re-setup cocoapods, delete pods caches, derived data etc. happens with Xcode quite a lot.

[krzyzanowskim]

Starting v1.3.4 I distribute pre-compiled release version of the framework for Apple platforms. https://github.com/krzyzanowskim/CryptoSwift/issues/833#issuecomment-727293595
If you use SPM integration, you should use an Optimized build that most likely solves the issue you experience. This is the only way I can think of to make it happen at the moment.