Decouple EncryptionParameters and Scheme

Author: fboemer

Benchmarks/RlweBenchmark/RlweBenchmark.swift

@@ -42,7 +42,7 @@ func getRandomPlaintextData<T: ScalarType>(count: Int, in range: Range<T>) -> [T
 }
 
 struct RlweBenchmarkContext<Scheme: HeScheme>: Sendable {
-    var encryptionParameters: EncryptionParameters<Scheme>
+    var encryptionParameters: EncryptionParameters<Scheme.Scalar>
     var context: Context<Scheme>
 
     let data: [Scheme.Scalar]
@@ -130,15 +130,15 @@ extension EncryptionParametersConfig: CustomStringConvertible {
 
 extension EncryptionParameters {
     init(config: EncryptionParametersConfig) throws {
-        let plaintextModuli = try Scheme.Scalar.generatePrimes(
+        let plaintextModuli = try Scalar.generatePrimes(
             significantBitCounts: config.plaintextModulusBits,
             preferringSmall: true,
             nttDegree: config.polyDegree)
-        let coefficientModuli = try Scheme.Scalar.generatePrimes(
+        let coefficientModuli = try Scalar.generatePrimes(
             significantBitCounts: config.coefficientModulusBits,
             preferringSmall: false,
             nttDegree: config.polyDegree)
-        self = try EncryptionParameters<Scheme>(
+        self = try EncryptionParameters<Scalar>(
             polyDegree: config.polyDegree,
             plaintextModulus: plaintextModuli[0],
             coefficientModuli: coefficientModuli,
@@ -160,10 +160,10 @@ func contextInitBenchmark<Scheme: HeScheme>(_: Scheme.Type, config: EncryptionPa
     {
         let benchmarkName = ["ContextInit", String(describing: Scheme.self), config.description].joined(separator: "/")
         Benchmark(benchmarkName, configuration: benchmarkConfiguration) { benchmark in
-            let encryptionParameters = try EncryptionParameters<Scheme>(config: config)
+            let encryptionParameters = try EncryptionParameters<Scheme.Scalar>(config: config)
             benchmark.startMeasurement()
             for _ in benchmark.scaledIterations {
-                try blackHole(_ = Context(encryptionParameters: encryptionParameters))
+                try blackHole(_ = Context<Scheme>(encryptionParameters: encryptionParameters))
             }
         }
     }

Snippets/.swiftformat

@@ -1 +1 @@
---maxwidth 81 # Copyright header is 81 characters
+--maxwidth 87 # Copyright header is 87 characters

Snippets/.swiftlint.yml

@@ -1,3 +1,3 @@
 line_length:
-  # Copyright header is 81 characters
-  warning: 81
+  # Copyright header is 87 characters
+  warning: 87

Snippets/HomomorphicEncryption/BasicsSnippet.swift

@@ -1,7 +1,7 @@
 // Example showing the basics.
 
 // snippet.hide
-// Copyright 2024 Apple Inc. and the Swift Homomorphic Encryption project authors
+// Copyright 2024-2025 Apple Inc. and the Swift Homomorphic Encryption project authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -22,9 +22,9 @@ import HomomorphicEncryption
 // We start by choosing some encryption parameters for the Bfv<UInt64> scheme.
 // *These encryption parameters are insecure, suitable for testing only.*
 let encryptParams =
-    try EncryptionParameters<Bfv<UInt64>>(from: .insecure_n_8_logq_5x18_logt_5)
+    try EncryptionParameters<UInt64>(from: .insecure_n_8_logq_5x18_logt_5)
 // Perform pre-computation for HE computation with these parameters.
-let context = try Context(encryptionParameters: encryptParams)
+let context = try Context<Bfv<UInt64>>(encryptionParameters: encryptParams)
 
 // We encode N values using coefficient encoding.
 let values: [UInt64] = [8, 5, 12, 12, 15, 0, 8, 5]

Snippets/HomomorphicEncryption/EncryptionParametersSnippet.swift

@@ -1,7 +1,7 @@
 // Choosing encryption parameters.
 
 // snippet.hide
-// Copyright 2024 Apple Inc. and the Swift Homomorphic Encryption project authors
+// Copyright 2024-2025 Apple Inc. and the Swift Homomorphic Encryption project authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -37,22 +37,20 @@ import HomomorphicEncryption
 // encryption parameters. Generally, the coefficient moduli should all be as
 // large as possible, while remaining under the maxLog2CoefficientModulus, and
 // as close to the same size as possible.
-let params4096 =
-    try EncryptionParameters<Bfv<UInt64>>(from: .n_4096_logq_27_28_28_logt_5)
-let params8192 =
-    try EncryptionParameters<Bfv<UInt64>>(from: .n_8192_logq_3x55_logt_24)
+let params4096 = try EncryptionParameters<UInt64>(from: .n_4096_logq_27_28_28_logt_5)
+let params8192 = try EncryptionParameters<UInt64>(from: .n_8192_logq_3x55_logt_24)
 
 // We can also create custom parameters.
 // For instance, for a very small HE circuit, N=2048 might suffice.
 // To maintain security, we ensure the coefficient modulus does not exceed the
 // maximum log2 coefficient modulus for post-quantum 128-bit security.
 let degree = 2048
-let maxLog2Q = try EncryptionParameters<Bfv<UInt64>>.maxLog2CoefficientModulus(
+let maxLog2Q = try EncryptionParameters<UInt64>.maxLog2CoefficientModulus(
     degree: degree,
     securityLevel: .quantum128)
 precondition(maxLog2Q == 41)
 // We can also stay in the range for 32-bit moduli, for faster runtimes.
-let max2BitModulus = EncryptionParameters<Bfv<UInt32>>.maxSingleModulus
+let max2BitModulus = EncryptionParameters<UInt32>.maxSingleModulus
 precondition(max2BitModulus.ceilLog2 == 30)
 
 // The coefficient moduli must be NTT-friendly, so we set nttDegree: degree.
@@ -73,21 +71,21 @@ let plaintextModulus = try UInt32.generatePrimes(
     preferringSmall: false)[0]
 // This custom parameter set has only a single coefficient modulus, so it is not
 // compatible with evaluation key operations.
-let customParams = try EncryptionParameters<Bfv<UInt32>>(
+let customUInt32Params = try EncryptionParameters<UInt32>(
     polyDegree: degree,
     plaintextModulus: plaintextModulus,
     coefficientModuli: coefficientModuli,
     errorStdDev: .stdDev32,
     securityLevel: .quantum128)
-precondition(!customParams.supportsSimdEncoding)
-precondition(!customParams.supportsEvaluationKey)
+precondition(!customUInt32Params.supportsSimdEncoding)
+precondition(!customUInt32Params.supportsEvaluationKey)
 
 // snippet.hide
 func summarize<Scheme: HeScheme>(
-    parameters: EncryptionParameters<Scheme>) throws
+    parameters: EncryptionParameters<Scheme.Scalar>, _: Scheme.Type) throws
 {
     let values = (0..<8).map { Scheme.Scalar($0) }
-    let context = try Context(encryptionParameters: parameters)
+    let context = try Context<Scheme>(encryptionParameters: parameters)
     let plaintext: Scheme.CoeffPlaintext = try context.encode(
         values: values,
         format: .coefficient)
@@ -106,6 +104,6 @@ func summarize<Scheme: HeScheme>(
         """)
 }
 
-try summarize(parameters: customParams)
-try summarize(parameters: params4096)
-try summarize(parameters: params8192)
+try summarize(parameters: customUInt32Params, Bfv<UInt32>.self)
+try summarize(parameters: params4096, Bfv<UInt64>.self)
+try summarize(parameters: params8192, Bfv<UInt64>.self)

Snippets/HomomorphicEncryption/EvaluationKeySnippet.swift

@@ -1,7 +1,7 @@
 // Example using an ``EvaluationKey``.
 
 // snippet.hide
-// Copyright 2024 Apple Inc. and the Swift Homomorphic Encryption project authors
+// Copyright 2024-2025 Apple Inc. and the Swift Homomorphic Encryption project authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -43,10 +43,10 @@ func checkDecryptsDecodes<Scheme: HeScheme>(
 precondition(PredefinedRlweParameters.insecure_n_8_logq_5x18_logt_5
     .supportsScalar(Bfv<UInt32>.Scalar.self))
 let encryptionParameters =
-    try EncryptionParameters<Bfv<UInt32>>(from: .insecure_n_8_logq_5x18_logt_5)
+    try EncryptionParameters<UInt32>(from: .insecure_n_8_logq_5x18_logt_5)
 precondition(encryptionParameters.plaintextModulus == 17)
 // Perform pre-computation for HE computation with these parameters.
-let context = try Context(encryptionParameters: encryptionParameters)
+let context = try Context<Bfv<UInt32>>(encryptionParameters: encryptionParameters)
 
 // We encode N values using SIMD encoding.
 // Each value is a Bfv<UInt32>.Scalar, which is UInt32.

Snippets/HomomorphicEncryption/MultiplicationSnippet.swift

@@ -1,7 +1,7 @@
 // Example showing HE multiplication.
 
 // snippet.hide
-// Copyright 2024 Apple Inc. and the Swift Homomorphic Encryption project authors
+// Copyright 2024-2025 Apple Inc. and the Swift Homomorphic Encryption project authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -31,10 +31,10 @@ precondition(PredefinedRlweParameters.insecure_n_8_logq_5x18_logt_5
 precondition(PredefinedRlweParameters.insecure_n_8_logq_5x18_logt_5
     .supportsScalar(UInt32.self))
 let encryptParams =
-    try EncryptionParameters<Bfv<UInt32>>(from: .insecure_n_8_logq_5x18_logt_5)
+    try EncryptionParameters<UInt32>(from: .insecure_n_8_logq_5x18_logt_5)
 precondition(encryptParams.plaintextModulus == 17)
 // Perform pre-computation for HE computation with these parameters.
-let context = try Context(encryptionParameters: encryptParams)
+let context = try Context<Bfv<UInt32>>(encryptionParameters: encryptParams)
 
 // We don't need to use all the slots in the encoding.
 // However, performing HE operations on ciphertexts with fewer slots doesn't give

Snippets/HomomorphicEncryption/NoiseBudgetSnippet.swift

@@ -1,7 +1,7 @@
 // Example for noise budget: ``Ciphertext/noiseBudget(using:variableTime:)``.
 
 // snippet.hide
-// Copyright 2024 Apple Inc. and the Swift Homomorphic Encryption project authors
+// Copyright 2024-2025 Apple Inc. and the Swift Homomorphic Encryption project authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -43,9 +43,9 @@ func checkDecryptsDecodes<Scheme: HeScheme>(
 // snippet.show
 // We start by choosing some encryption parameters for the Bfv<UInt32> scheme.
 let encryptionParameters =
-    try EncryptionParameters<Bfv<UInt32>>(from: .insecure_n_8_logq_5x18_logt_5)
+    try EncryptionParameters<UInt32>(from: .insecure_n_8_logq_5x18_logt_5)
 // Perform pre-computation for HE computation with these parameters.
-let context = try Context(encryptionParameters: encryptionParameters)
+let context = try Context<Bfv<UInt32>>(encryptionParameters: encryptionParameters)
 
 // We encode N values in coefficient format and SIMD encoding.
 let values = (0..<8).map { UInt32($0) }

Snippets/HomomorphicEncryption/SerializationSnippet.swift

@@ -1,7 +1,7 @@
 // Example for serialization.
 
 // snippet.hide
-// Copyright 2024 Apple Inc. and the Swift Homomorphic Encryption project authors
+// Copyright 2024-2025 Apple Inc. and the Swift Homomorphic Encryption project authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -34,9 +34,9 @@ extension SerializedCiphertext {
 
 // We start by choosing some encryption parameters for the Bfv<UInt32> scheme.
 let encryptionParameters =
-    try EncryptionParameters<Bfv<UInt32>>(from: .n_4096_logq_27_28_28_logt_5)
+    try EncryptionParameters<UInt32>(from: .n_4096_logq_27_28_28_logt_5)
 // Perform pre-computation for HE computation with these parameters.
-let context = try Context(encryptionParameters: encryptionParameters)
+let context = try Context<Bfv<UInt32>>(encryptionParameters: encryptionParameters)
 
 // We encode some values in coefficient format and coefficient encoding.
 let values = (0..<8).map { UInt32($0) }

Sources/BenchmarkUtilities/PirBenchmarkUtilities.swift

@@ -57,10 +57,10 @@ extension PirEncryptionParametersConfig: CustomStringConvertible {
 
 extension EncryptionParameters {
     init(from config: PirEncryptionParametersConfig) throws {
-        let plaintextModulus = try Scheme.Scalar.generatePrimes(
+        let plaintextModulus = try Scalar.generatePrimes(
             significantBitCounts: [config.plaintextModulusBits],
             preferringSmall: true)[0]
-        let coefficientModuli = try Scheme.Scalar.generatePrimes(
+        let coefficientModuli = try Scalar.generatePrimes(
             significantBitCounts: config.coefficientModulusBits,
             preferringSmall: false,
             nttDegree: config.polyDegree)
@@ -88,7 +88,7 @@ struct ProcessBenchmarkContext<Server: IndexPirServer> {
     init(server _: Server.Type, pirConfig: IndexPirConfig,
          parameterConfig: PirEncryptionParametersConfig) throws
     {
-        let encryptParameter: EncryptionParameters<Server.Scheme> =
+        let encryptParameter: EncryptionParameters<Server.Scheme.Scalar> =
             try EncryptionParameters(from: parameterConfig)
         self.database = getDatabaseForTesting(
             numberOfEntries: pirConfig.entryCount,
@@ -169,8 +169,9 @@ struct IndexPirBenchmarkContext<Server: IndexPirServer, Client: IndexPirClient>
         pirConfig: IndexPirConfig,
         parameterConfig: PirEncryptionParametersConfig) throws
     {
-        let encryptParameter: EncryptionParameters<Server.Scheme> = try EncryptionParameters(from: parameterConfig)
-        let context = try Context(encryptionParameters: encryptParameter)
+        let encryptParameter: EncryptionParameters<Server.Scheme.Scalar> =
+            try EncryptionParameters(from: parameterConfig)
+        let context = try Context<Server.Scheme>(encryptionParameters: encryptParameter)
         let indexPirParameters = Server.generateParameter(config: pirConfig, with: context)
         let database = getDatabaseForTesting(
             numberOfEntries: pirConfig.entryCount,
@@ -283,9 +284,9 @@ struct KeywordPirBenchmarkContext<IndexServer: IndexPirServer, IndexClient: Inde
         parameterConfig: PirEncryptionParametersConfig,
         keyCompression: PirKeyCompressionStrategy) async throws
     {
-        let encryptParameter: EncryptionParameters<Server.Scheme> = try EncryptionParameters(from: parameterConfig)
-        let context = try Context(encryptionParameters: encryptParameter)
-
+        let encryptParameter: EncryptionParameters<Server.Scheme.Scalar> =
+            try EncryptionParameters(from: parameterConfig)
+        let context = try Context<Server.Scheme>(encryptionParameters: encryptParameter)
         let rows = (0..<databaseCount).map { index in KeywordValuePair(
             keyword: [UInt8](String(index).utf8),
             value: (0..<payloadSize).map { _ in UInt8.random(in: 0..<UInt8.max) })