diff --git a/Sources/Keycard/Crypto.swift b/Sources/Keycard/Crypto.swift
index 71137b9..1ecd17c 100644
--- a/Sources/Keycard/Crypto.swift
+++ b/Sources/Keycard/Crypto.swift
@@ -46,6 +46,17 @@ class Crypto {
         CCCrypt(CCOperation(kCCEncrypt), CCAlgorithm(kCCAlgorithmDES), CCOptions(0), &tmpKey, key.count, &tmpIV, &tmpData, data.count, &out, out.count, &encrypted)
         return out
     }
+    
+    func desDec(data: [UInt8], iv: [UInt8], key: [UInt8]) -> [UInt8] {
+        var out: [UInt8] = [UInt8](repeating: 0, count: data.count)
+        var decrypted: Int = 0
+        var tmpKey = key
+        var tmpData = data
+        var tmpIV = iv
+        
+        CCCrypt(CCOperation(kCCDecrypt), CCAlgorithm(kCCAlgorithmDES), CCOptions(0), &tmpKey, key.count, &tmpIV, &tmpData, data.count, &out, out.count, &decrypted)
+        return out
+    }
        
     func des3Enc(data: [UInt8], iv: [UInt8], key: [UInt8]) -> [UInt8] {
         var out: [UInt8] = [UInt8](repeating: 0, count: data.count)
@@ -58,6 +69,17 @@ class Crypto {
         return out
     }
     
+    func des3Dec(data: [UInt8], iv: [UInt8], key: [UInt8]) -> [UInt8] {
+        var out: [UInt8] = [UInt8](repeating: 0, count: data.count)
+        var decrypted: Int = 0
+        var tmpKey = key
+        var tmpData = data
+        var tmpIV = iv
+        
+        CCCrypt(CCOperation(kCCDecrypt), CCAlgorithm(kCCAlgorithm3DES), CCOptions(0), &tmpKey, key.count, &tmpIV, &tmpData, data.count, &out, out.count, &decrypted)
+        return out
+    }
+    
     func des3Mac(data: [UInt8], iv: [UInt8], key: [UInt8]) -> [UInt8] {
         let enc: [UInt8] = des3Enc(data: data, iv: iv, key: key)
         return Array(enc.suffix(8))
diff --git a/Sources/Keycard/Keycard.swift b/Sources/Keycard/Keycard.swift
index b4b4699..3148413 100644
--- a/Sources/Keycard/Keycard.swift
+++ b/Sources/Keycard/Keycard.swift
@@ -127,8 +127,8 @@ public enum Identifier: String {
 }
 
 public enum GlobalPlatformKeys: String {
-    case defaultKeys = "404142434445464748494a4b4c4d4e4f"
-    case statusKeys = "c212e073ff8b4bbfaff4de8ab655221f"
+    case defaultKeys = "404142434445464748494a4b4c4d4e4f4041424344454647"
+    case statusKeys = "c212e073ff8b4bbfaff4de8ab655221fc212e073ff8b4bbf"
     
     public var val: [UInt8] {
         return rawValue.hexToBytes
diff --git a/Tests/KeycardTests/CryptoTests.swift b/Tests/KeycardTests/CryptoTests.swift
index a315722..a1febd9 100644
--- a/Tests/KeycardTests/CryptoTests.swift
+++ b/Tests/KeycardTests/CryptoTests.swift
@@ -2,8 +2,7 @@ import XCTest
 @testable import Keycard
 
 final class CryptoTests: XCTestCase {
-
-    func test_encrypt_decrypt() {
+    func testAES() {
         let plaintext = "Hello, World!"
         let plaintextBytes = [UInt8](plaintext.utf8)
 
@@ -17,4 +16,25 @@ final class CryptoTests: XCTestCase {
         XCTAssertEqual(decryptedText, plaintext)
     }
 
+    func testDES() {
+        let plaintext = "Hello, World!"
+        let paddedData = Crypto.shared.iso7816_4Pad(data: [UInt8](plaintext.utf8), blockSize: 8)
+        
+        let iv = Crypto.shared.random(count: 8)
+        let key = GlobalPlatformKeys.statusKeys.val
+
+        let encrypted = Crypto.shared.desEnc(data: paddedData, iv: iv, key: Crypto.shared.resizeDESKey8(key))
+        let decrypted = Crypto.shared.desDec(data: encrypted, iv: iv, key: Crypto.shared.resizeDESKey8(key))
+        XCTAssertEqual(decrypted, paddedData)
+        
+        let encrypted3 = Crypto.shared.des3Enc(data: paddedData, iv: iv, key: key)
+        let decrypted3 = Crypto.shared.des3Dec(data: encrypted3, iv: iv, key: key)
+        XCTAssertEqual(decrypted3, paddedData)
+        
+        let mac = Crypto.shared.des3Mac(data: paddedData, iv: iv, key: key)
+        XCTAssertEqual(encrypted3.suffix(8), mac)
+        
+        let fullMac = Crypto.shared.des3FullMac(data: paddedData, iv: iv, key: key)
+        XCTAssertEqual(fullMac.count, 8)
+    }
 }
diff --git a/Tests/KeycardTests/GlobalPlatformTests.swift b/Tests/KeycardTests/GlobalPlatformTests.swift
new file mode 100644
index 0000000..49d4e60
--- /dev/null
+++ b/Tests/KeycardTests/GlobalPlatformTests.swift
@@ -0,0 +1,22 @@
+import XCTest
+@testable import Keycard
+
+final class GlobalPlatformTests: XCTestCase {
+    func testSCP02() {
+        let scp02 = SCP02(channel: TestCardChannel())
+        let hostChallenge = Crypto.shared.random(count: 8)
+        var cardChallenge = Crypto.shared.random(count: 8)
+        cardChallenge[0] = 0x00
+        cardChallenge[1] = 0x0f
+        
+        var cardData = [UInt8](repeating: 0, count: 12)
+        cardData.append(contentsOf: cardChallenge)
+        
+        let encKey = scp02.deriveSessionKey(key: GlobalPlatformKeys.statusKeys.val, seq: [0x00, 0x0f], purpose: SCP02.derivationPurposeEnc)
+        scp02.encKey = encKey
+        cardData.append(contentsOf: scp02.generateCryptogram(challenge1: hostChallenge, challenge2: cardChallenge))
+        
+        XCTAssertTrue(scp02.verifyChallenge(hostChallenge: hostChallenge, key: GlobalPlatformKeys.statusKeys.val, cardResponse: cardData))
+        XCTAssertFalse(scp02.verifyChallenge(hostChallenge: hostChallenge, key: GlobalPlatformKeys.defaultKeys.val, cardResponse: cardData))
+    }
+}