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IOS-8008 Sign hashes with different sizes (#382)
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,56 @@ | ||
| // | ||
| // ChunkHashesUtil.swift | ||
| // TangemSdk | ||
| // | ||
| // Created by Alexander Osokin on 31.10.2024. | ||
| // Copyright © 2024 Tangem AG. All rights reserved. | ||
| // | ||
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| struct ChunkHashesUtil { | ||
| func chunkHashes(_ hashes: [Data]) -> [Chunk] { | ||
| let hashes = hashes.enumerated().map { Hash(index: $0.offset, data: $0.element) } | ||
| let hashesBySize = Dictionary(grouping: hashes, by: { $0.data.count }) | ||
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| let chunks = hashesBySize.flatMap { hashesGroup in | ||
| let hashSize = hashesGroup.key | ||
| let chunkSize = getChunkSize(for: hashSize) | ||
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| let chunkedHashes = hashesGroup.value.chunked(into: chunkSize) | ||
| let chunks = chunkedHashes.map { Chunk(hashSize: hashSize, hashes: $0) } | ||
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| return chunks | ||
| } | ||
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| return chunks | ||
| } | ||
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| func getChunkSize(for hashSize: Int) -> Int { | ||
| /// These devices are not able to sign long hashes. | ||
| if NFCUtils.isPoorNfcQualityDevice { | ||
| return Constants.maxChunkSizePoorNfcQualityDevice | ||
| } | ||
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| guard hashSize > 0 else { | ||
| return Constants.maxChunkSize | ||
| } | ||
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| let estimatedChunkSize = Constants.packageSize / hashSize | ||
| let chunkSize = max(1, min(estimatedChunkSize, Constants.maxChunkSize)) | ||
| return chunkSize | ||
| } | ||
| } | ||
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| // MARK: - Constants | ||
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| private extension ChunkHashesUtil { | ||
| enum Constants { | ||
| /// The max answer is 1152 bytes (unencrypted) and 1120 (encrypted). The worst case is 8 hashes * 64 bytes for ed + 512 bytes of signatures + cardId, SignedHashes + TLV + SW is ok. | ||
| static let packageSize = 512 | ||
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| /// Card limitation | ||
| static let maxChunkSize = 10 | ||
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| /// Empirical value | ||
| static let maxChunkSizePoorNfcQualityDevice = 2 | ||
| } | ||
| } |
51 changes: 51 additions & 0 deletions
51
TangemSdk/TangemSdk/Operations/Sign/ChunkedHashesContainer.swift
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,51 @@ | ||
| // | ||
| // ChunkedHashesContainer.swift | ||
| // TangemSdk | ||
| // | ||
| // Created by Alexander Osokin on 31.10.2024. | ||
| // Copyright © 2024 Tangem AG. All rights reserved. | ||
| // | ||
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| import Foundation | ||
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| struct ChunkedHashesContainer { | ||
| var isEmpty: Bool { chunks.isEmpty } | ||
| let chunksCount: Int | ||
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| private(set) var currentChunkIndex: Int = 0 | ||
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| private let chunks: [Chunk] | ||
| private var signedChunks: [SignedChunk] = [] | ||
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| init(hashes: [Data]) { | ||
| self.chunks = ChunkHashesUtil().chunkHashes(hashes) | ||
| self.chunksCount = chunks.count | ||
| } | ||
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| func getCurrentChunk() throws -> Chunk { | ||
| guard currentChunkIndex < chunks.count else { | ||
| throw ChunkedHashesContainerError.processingError | ||
| } | ||
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| return chunks[currentChunkIndex] | ||
| } | ||
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| mutating func addSignedChunk(_ signedChunk: SignedChunk) { | ||
| signedChunks.append(signedChunk) | ||
| currentChunkIndex += 1 | ||
| } | ||
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| func getSignatures() -> [Data] { | ||
| let signedHashes = signedChunks.flatMap { $0.signedHashes }.sorted() | ||
| let signatures = signedHashes.map { $0.signature } | ||
| return signatures | ||
| } | ||
| } | ||
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| // MARK: - ChunkedHashesContainerError | ||
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| enum ChunkedHashesContainerError: Error { | ||
| case processingError | ||
| } | ||
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