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// Copyright 2014 The Closure Library Authors. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//      http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS-IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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/**
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 * @fileoverview SHA-512/256 cryptographic hash.
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 *
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 * WARNING:  SHA-256 and SHA-512/256 are different members of the SHA-2
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 * family of hashes.  Although both give 32-byte results, the two results
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 * should bear no relationship to each other.
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 *
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 * Please be careful before using this hash function.
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 * <p>
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 * Usage:
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 *   var sha512_256 = new goog.crypt.Sha512_256();
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 *   sha512_256.update(bytes);
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 *   var hash = sha512_256.digest();
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 *
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 * @author [email protected] (Frank Yellin)
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 */
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goog.provide('goog.crypt.Sha512_256');
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goog.require('goog.crypt.Sha2_64bit');
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/**
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 * Constructs a SHA-512/256 cryptographic hash.
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 *
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 * @constructor
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 * @extends {goog.crypt.Sha2_64bit}
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 * @final
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 * @struct
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 */
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goog.crypt.Sha512_256 = function() {
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  goog.crypt.Sha512_256.base(
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      this, 'constructor', 4 /* numHashBlocks */,
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      goog.crypt.Sha512_256.INIT_HASH_BLOCK_);
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};
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goog.inherits(goog.crypt.Sha512_256, goog.crypt.Sha2_64bit);
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/** @private {!Array<number>} */
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goog.crypt.Sha512_256.INIT_HASH_BLOCK_ = [
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  // Section 5.3.6.2 of
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  // csrc.nist.gov/publications/fips/fips180-4/fips-180-4.pdf
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  0x22312194, 0xFC2BF72C,  // H0
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  0x9F555FA3, 0xC84C64C2,  // H1
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  0x2393B86B, 0x6F53B151,  // H2
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  0x96387719, 0x5940EABD,  // H3
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  0x96283EE2, 0xA88EFFE3,  // H4
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  0xBE5E1E25, 0x53863992,  // H5
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  0x2B0199FC, 0x2C85B8AA,  // H6
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  0x0EB72DDC, 0x81C52CA2   // H7
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];
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