Release 2.6.0

Package.swift

@@ -14,9 +14,9 @@ let package = Package(
     ],
     dependencies: [
         // Dependencies declare other packages that this package depends on.
-        .package(url: "https://github.com/leif-ibsen/BigInt", from: "1.17.0"),
-        .package(url: "https://github.com/leif-ibsen/ASN1", from: "2.5.0"),
-        .package(url: "https://github.com/leif-ibsen/Digest", from: "1.6.0"),
+        .package(url: "https://github.com/leif-ibsen/BigInt", from: "1.19.0"),
+        .package(url: "https://github.com/leif-ibsen/ASN1", from: "2.6.0"),
+        .package(url: "https://github.com/leif-ibsen/Digest", from: "1.8.0"),
     ],
     targets: [
         // Targets are the basic building blocks of a package. A target can define a module or a test suite.

Sources/SwiftHPKE/Exception.swift

@@ -11,8 +11,6 @@ public enum HPKEException: Error, CustomStringConvertible {
     /// Textual description of `self`
     public var description: String {
         switch self {
-        case .base64:
-            return "Base64 decoding exception"
         case .asn1Structure:
             return "ASN1 structure is wrong"
         case .pemStructure:
@@ -38,9 +36,6 @@ public enum HPKEException: Error, CustomStringConvertible {
         }
     }
 
-    /// Base64 decoding exception
-    case base64
-
     /// ASN1 structure is wrong
     case asn1Structure
 

Sources/SwiftHPKE/PrivateKey.swift

@@ -7,6 +7,7 @@
 
 import ASN1
 import BigInt
+import Digest
 
 public struct PrivateKey: CustomStringConvertible, Equatable {
 
@@ -146,7 +147,10 @@ public struct PrivateKey: CustomStringConvertible, Equatable {
     ///   - pem: The PEM encoding of the key
     /// - Throws: An exception if the PEM encoding is wrong
     public init(pem: String) throws {
-        try self.init(der: Base64.pemDecode(pem, "PRIVATE KEY"))
+        guard let der = Base64.pemDecode(pem, "PRIVATE KEY") else {
+            throw HPKEException.pemStructure
+        }
+        try self.init(der: der)
     }
 
 

Sources/SwiftHPKE/PublicKey.swift

@@ -7,6 +7,7 @@
 
 import ASN1
 import BigInt
+import Digest
 
 public struct PublicKey: CustomStringConvertible, Equatable {
 
@@ -143,7 +144,10 @@ public struct PublicKey: CustomStringConvertible, Equatable {
     ///   - pem: The PEM encoding of the key
     /// - Throws: An exception if the PEM encoding is wrong
     public init(pem: String) throws {
-        try self.init(der: Base64.pemDecode(pem, "PUBLIC KEY"))
+        guard let der = Base64.pemDecode(pem, "PUBLIC KEY") else {
+            throw HPKEException.pemStructure
+        }
+        try self.init(der: der)
     }
 
 

Sources/SwiftHPKE/SwiftHPKE.docc/Articles/KeyManagement.md

@@ -44,9 +44,9 @@ import SwiftHPKE
 let pubKeyPem =
 """
 -----BEGIN PUBLIC KEY-----
-MHYwEAYHKoZIzj0CAQYFK4EEACIDYgAEQW/MahMwMTFjwY95uOEdfBVC7HrQhTGG
-TwxiPlgDiARqC6y6EQ1Ajkuhe4A02WOltRYQRXKytzspOR25UfgtagURAwxVFYzR
-9cmi6FRmvvq/Tsigd/dAi4FNjniR7/Pg
+MHYwEAYHKoZIzj0CAQYFK4EEACIDYgAEQW/MahMwMTFjwY95uOEdfBVC7HrQhTGGTwxiPlgDiARq
+C6y6EQ1Ajkuhe4A02WOltRYQRXKytzspOR25UfgtagURAwxVFYzR9cmi6FRmvvq/Tsigd/dAi4FN
+jniR7/Pg
 -----END PUBLIC KEY-----
 """
 let pubKey = try PublicKey(pem: pubKeyPem)
@@ -55,11 +55,10 @@ let pubKey = try PublicKey(pem: pubKeyPem)
 let privKeyPem =
 """
 -----BEGIN PRIVATE KEY-----
-MIG/AgEAMBAGByqGSM49AgEGBSuBBAAiBIGnMIGkAgEBBDBmpNziSYmGoWwl7apJ
-M9ZdDBxkJqmxMScHGXG45ZQXSv7fIuJlsSwxK76nUiiO7gigBwYFK4EEACKhZANi
-AARBb8xqEzAxMWPBj3m44R18FULsetCFMYZPDGI+WAOIBGoLrLoRDUCOS6F7gDTZ
-Y6W1FhBFcrK3Oyk5HblR+C1qBREDDFUVjNH1yaLoVGa++r9OyKB390CLgU2OeJHv
-8+A=
+MIG/AgEAMBAGByqGSM49AgEGBSuBBAAiBIGnMIGkAgEBBDBmpNziSYmGoWwl7apJM9ZdDBxkJqmx
+MScHGXG45ZQXSv7fIuJlsSwxK76nUiiO7gigBwYFK4EEACKhZANiAARBb8xqEzAxMWPBj3m44R18
+FULsetCFMYZPDGI+WAOIBGoLrLoRDUCOS6F7gDTZY6W1FhBFcrK3Oyk5HblR+C1qBREDDFUVjNH1
+yaLoVGa++r9OyKB390CLgU2OeJHv8+A=
 -----END PRIVATE KEY-----
 """
 let privKey = try PrivateKey(pem: privKeyPem)

Sources/SwiftHPKE/SwiftHPKE.docc/SwiftHPKE.md

@@ -108,17 +108,17 @@ To use SwiftHPKE, in your project *Package.swift* file add a dependency like
 
 ```swift
 dependencies: [
-  .package(url: "https://github.com/leif-ibsen/SwiftHPKE", from: "2.5.0"),
+  .package(url: "https://github.com/leif-ibsen/SwiftHPKE", from: "2.6.0"),
 ]
 ```
 
 SwiftHPKE itself depends on the ASN1, BigInt and Digest packages
 
 ```swift
 dependencies: [
-  .package(url: "https://github.com/leif-ibsen/ASN1", from: "2.5.0"),
-  .package(url: "https://github.com/leif-ibsen/BigInt", from: "1.17.0"),
-  .package(url: "https://github.com/leif-ibsen/Digest", from: "1.6.0"),
+  .package(url: "https://github.com/leif-ibsen/ASN1", from: "2.6.0"),
+  .package(url: "https://github.com/leif-ibsen/BigInt", from: "1.19.0"),
+  .package(url: "https://github.com/leif-ibsen/Digest", from: "1.8.0"),
 ],
 ```
 
@@ -140,7 +140,6 @@ for iOS the version must be at least 13, and for watchOS the version must be at
 - ``SwiftHPKE/CipherSuite``
 - ``SwiftHPKE/PrivateKey``
 - ``SwiftHPKE/PublicKey``
-- ``SwiftHPKE/Base64``
 
 ### Type Aliases
 

Sources/SwiftHPKE/X255_448/Field25519.swift

@@ -285,28 +285,21 @@ struct Field25519: CustomStringConvertible {
     }
 
     func invert() -> Field25519 {
-        let z2 = self.square()
-        var t = z2.square(2)
-        let z9 = t.mul(self)
-        let z11 = z9.mul(z2)
-        t = z11.square()
-        let z2_5_0 = t.mul(z9)
-        t = z2_5_0.square(5)
-        let z2_10_0 = t.mul(z2_5_0)
-        t = z2_10_0.square(10)
-        let z2_20_0 = t.mul(z2_10_0)
-        t = z2_20_0.square(20)
-        t = t.mul(z2_20_0)
-        t = t.square(10)
-        let z2_50_0 = t.mul(z2_10_0)
-        t = z2_50_0.square(50)
-        let z2_100_0 = t.mul(z2_50_0)
-        t = z2_100_0.square(100)
-        t = t.mul(z2_100_0)
-        t = t.square(50)
-        t = t.mul(z2_50_0)
-        t = t.square(5)
-        return t.mul(z11)
+
+        // 2^255 - 19 - 2 bit pattern: 250 x 1   1 x 0   1 x 1   1 x 0   2 x 1
+        // Addition chain: 1 2 3 5 10 15 25 50 75 125 250
+
+        let x2 = self.square().mul(self)
+        let x3 = x2.square().mul(self)
+        let x5 = x3.square(2).mul(x2)
+        let x10 = x5.square(5).mul(x5)
+        let x15 = x10.square(5).mul(x5)
+        let x25 = x15.square(10).mul(x10)
+        let x50 = x25.square(25).mul(x25)
+        let x75 = x50.square(25).mul(x25)
+        let x125 = x75.square(50).mul(x50)
+        let x250 = x125.square(125).mul(x125)        
+        return x250.square(2).mul(self).square(3).mul(x2)
     }
 
 }

Sources/SwiftHPKE/X255_448/Field448.swift

@@ -248,6 +248,10 @@ struct Field448: CustomStringConvertible {
     }
 
     func invert() -> Field448 {
+
+        // 2^448 - 2^224 - 1 - 2 bit pattern: 223 x 1   1 x 0   222 x 1   1 x 0   1 x 1
+        // Addition chain: 1 2 3 6 9 18 19 37 74 111 222 223
+
         let x2 = self.square().mul(self)
         let x3 = x2.square().mul(self)
         let x6 = x3.square(3).mul(x3)