//
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// CryptoSwift
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//
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// Copyright (C) 2014-2022 Marcin Krzyżanowski <marcin@krzyzanowskim.com>
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// This software is provided 'as-is', without any express or implied warranty.
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//
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// In no event will the authors be held liable for any damages arising from the use of this software.
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//
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// Permission is granted to anyone to use this software for any purpose,including commercial applications, and to alter it and redistribute it freely, subject to the following restrictions:
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//
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// - The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation is required.
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// - Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
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// - This notice may not be removed or altered from any source or binary distribution.
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//
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public final class HMAC: Authenticator {
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public enum Error: Swift.Error {
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case authenticateError
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case invalidInput
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}
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public enum Variant {
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case md5
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case sha1
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case sha2(SHA2.Variant)
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case sha3(SHA3.Variant)
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@available(*, deprecated, message: "Use sha2(variant) instead.")
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case sha256, sha384, sha512
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var digestLength: Int {
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switch self {
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case .sha1:
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return SHA1.digestLength
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case .sha256:
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return SHA2.Variant.sha256.digestLength
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case .sha384:
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return SHA2.Variant.sha384.digestLength
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case .sha512:
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return SHA2.Variant.sha512.digestLength
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case .sha2(let variant):
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return variant.digestLength
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case .sha3(let variant):
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return variant.digestLength
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case .md5:
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return MD5.digestLength
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}
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}
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func calculateHash(_ bytes: Array<UInt8>) -> Array<UInt8> {
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switch self {
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case .sha1:
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return Digest.sha1(bytes)
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case .sha256:
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return Digest.sha256(bytes)
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case .sha384:
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return Digest.sha384(bytes)
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case .sha512:
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return Digest.sha512(bytes)
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case .sha2(let variant):
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return Digest.sha2(bytes, variant: variant)
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case .sha3(let variant):
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return Digest.sha3(bytes, variant: variant)
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case .md5:
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return Digest.md5(bytes)
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}
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}
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func blockSize() -> Int {
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switch self {
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case .md5:
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return MD5.blockSize
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case .sha1:
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return SHA1.blockSize
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case .sha256:
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return SHA2.Variant.sha256.blockSize
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case .sha384:
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return SHA2.Variant.sha384.blockSize
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case .sha512:
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return SHA2.Variant.sha512.blockSize
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case .sha2(let variant):
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return variant.blockSize
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case .sha3(let variant):
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return variant.blockSize
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}
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}
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}
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var key: Array<UInt8>
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let variant: Variant
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public init(key: Array<UInt8>, variant: HMAC.Variant = .md5) {
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self.variant = variant
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self.key = key
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if key.count > variant.blockSize() {
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let hash = variant.calculateHash(key)
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self.key = hash
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}
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if key.count < variant.blockSize() {
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self.key = ZeroPadding().add(to: key, blockSize: variant.blockSize())
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}
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}
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// MARK: Authenticator
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public func authenticate(_ bytes: Array<UInt8>) throws -> Array<UInt8> {
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var opad = Array<UInt8>(repeating: 0x5c, count: variant.blockSize())
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for idx in self.key.indices {
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opad[idx] = self.key[idx] ^ opad[idx]
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}
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var ipad = Array<UInt8>(repeating: 0x36, count: variant.blockSize())
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for idx in self.key.indices {
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ipad[idx] = self.key[idx] ^ ipad[idx]
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}
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let ipadAndMessageHash = self.variant.calculateHash(ipad + bytes)
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let result = self.variant.calculateHash(opad + ipadAndMessageHash)
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// return Array(result[0..<10]) // 80 bits
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return result
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}
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}
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