Implementation of PKCS5.PBKDF2.

CryptoSwift.xcodeproj/project.pbxproj

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CryptoSwiftTests/PBKDF2Tests.swift

@@ -0,0 +1,29 @@
+//
+//  PBKDF2Tests.swift
+//  CryptoSwift
+//
+//  Created by Marcin Krzyzanowski on 04/04/16.
+//  Copyright © 2016 Marcin Krzyzanowski. All rights reserved.
+//
+
+import XCTest
+@testable import CryptoSwift
+
+class PBKDF2Tests: XCTestCase {
+
+    override func setUp() {
+        super.setUp()
+    }
+
+    override func tearDown() {
+        super.tearDown()
+    }
+
+    func test1() {
+        let p = try! PKCS5.PBKDF2(password: "s33krit".utf8.map({ $0 }), salt: "nacl".utf8.map({ $0 }), iterations: 2, keyLength: 123, hashVariant: .sha1)
+        let value = p.calculate()
+        print(value.toHexString());
+        print("done")
+    }
+
+}

Sources/CryptoSwift/PKCS5.swift

@@ -1,50 +0,0 @@
-//
-//  PKCS.swift
-//  CryptoSwift
-//
-//  Created by Marcin Krzyzanowski on 12/03/15.
-//  Copyright (c) 2015 Marcin Krzyzanowski. All rights reserved.
-//
-//  PKCS is a group of public-key cryptography standards devised 
-//  and published by RSA Security Inc, starting in the early 1990s.
-//
-//  PKCS#5 http://tools.ietf.org/html/rfc2898
-
-//public struct PKCS5 {
-//}
-//
-//extension PKCS5 {
-//    //
-//    // PBKDF2 - Password-Based Key Derivation Function 2. Key stretching technique.
-//    //          DK = PBKDF2(PRF, Password, Salt, c, dkLen)
-//    //
-//    struct PBKDF2 {
-//        typealias Bytes = [UInt8]
-//        private func calc(# hash:Hash,  password:Bytes, salt:Bytes, c:Int, dkLen:Int) -> [UInt8]? {
-//            if (dkLen > Int(pow(2,32) as Float - 1)) {
-//                println("ERROR: derived key too long");
-//                return nil
-//            }
-//
-//            if let prf = HMAC(password, variant: .sha256) { //FIXME: hardcoded SHA256
-//                let hLen = prf.variant.size
-//                let numBlocks = Int(ceilf(Float(dkLen) / Float(hLen)))  // l
-//                let lastBlockOctets = dkLen - (1 - numBlocks) * hLen    // r
-//                // blocks
-//                for block in 1...numBlocks {
-//                    // for each block T_i = U_1 ^ U_2 ^ ... ^ U_iter
-//                    // U_1 = PRF(password, salt || uint(i))
-//                    var uinti = [UInt8](count: 4, repeatedValue: 0)
-//                    uinti[0] = UInt8(block >> 24)
-//                    uinti[1] = UInt8(block >> 16)
-//                    uinti[2] = UInt8(block >> 8)
-//                    uinti[3] = UInt8(block)
-//                    if let dk = prf.authenticate(message: salt + uinti) {
-//                        let T = dk[dk.count - hLen]
-//                    }
-//                }
-//            }
-//            return nil
-//        }
-//    }
-//}

Sources/CryptoSwift/PKCS5/PBKDF2.swift

@@ -0,0 +1,78 @@
+//
+//  PBKDF2.swift
+//  CryptoSwift
+//
+//  Created by Marcin Krzyzanowski on 05/04/16.
+//  Copyright © 2016 Marcin Krzyzanowski. All rights reserved.
+//
+
+public extension PKCS5 {
+    // PBKDF2 - Password-Based Key Derivation Function 2. Key stretching technique.
+    //          DK = PBKDF2(PRF, Password, Salt, c, dkLen)
+    public struct PBKDF2 {
+
+        public enum Error: ErrorType {
+            case InvalidInput
+        }
+
+        private let salt: [UInt8]
+        private let iterations: Int // c
+        private let numBlocks: UInt  // l
+        private let prf: HMAC
+
+        init(password: [UInt8], salt: [UInt8], iterations: Int /* c */, keyLength: Int /* dkLen */ , hashVariant: HMAC.Variant = .sha256) throws {
+            guard let prf = HMAC(password, variant: hashVariant) where (keyLength <= Int(pow(2,32) as Float - 1)) && (iterations > 0) && (password.count > 0) && (salt.count > 0) else {
+                throw Error.InvalidInput
+            }
+
+            self.salt = salt
+            self.iterations = iterations
+            self.prf = prf
+            self.numBlocks = UInt(ceil(Double(keyLength) / Double(prf.variant.size)))  // l = ceil(keyLength / hLen)
+        }
+
+        func calculate() -> [UInt8] {
+            var ret = [UInt8]()
+            for i in 1...self.numBlocks {
+                // for each block T_i = U_1 ^ U_2 ^ ... ^ U_iter
+                if let value = calculateBlock(salt: self.salt, blockNum: i) {
+                    ret.appendContentsOf(value)
+                }
+            }
+            return ret
+        }
+    }
+}
+
+private extension PKCS5.PBKDF2 {
+    private func INT(i: UInt) -> [UInt8] {
+        var inti = [UInt8](count: 4, repeatedValue: 0)
+        inti[0] = UInt8((i >> 24) & 0xFF)
+        inti[1] = UInt8((i >> 16) & 0xFF)
+        inti[2] = UInt8((i >> 8) & 0xFF)
+        inti[3] = UInt8(i & 0xFF)
+        return inti
+    }
+
+    // F (P, S, c, i) = U_1 \xor U_2 \xor ... \xor U_c
+    // U_1 = PRF (P, S || INT (i))
+    private func calculateBlock(salt salt: [UInt8], blockNum: UInt) -> [UInt8]? {
+        guard let u1 = prf.authenticate(message: salt + INT(blockNum)) else {
+            return nil
+        }
+
+        var u = u1
+        var ret = u
+        if self.iterations > 1 {
+            // U_2 = PRF (P, U_1) ,
+            // U_c = PRF (P, U_{c-1}) .
+            for _ in 2...self.iterations {
+                u = prf.authenticate(message: u)!
+                for x in 0..<ret.count {
+                    ret[x] = ret[x] ^ u[x]
+                }
+            }
+        }
+        return ret
+    }
+}

Sources/CryptoSwift/PKCS5/PKCS5.swift

@@ -0,0 +1,15 @@
+//
+//  PKCS.swift
+//  CryptoSwift
+//
+//  Created by Marcin Krzyzanowski on 12/03/15.
+//  Copyright (c) 2015 Marcin Krzyzanowski. All rights reserved.
+//
+//  PKCS is a group of public-key cryptography standards devised 
+//  and published by RSA Security Inc, starting in the early 1990s.
+//
+
+public enum PKCS5 {
+    //  PKCS#5 http://tools.ietf.org/html/rfc2898
+}
+