HMACSHA512.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / FX-1434 / FX-1434 / 1.0 / untmp / whidbey / REDBITS / ndp / clr / src / BCL / System / Security / Cryptography / HMACSHA512.cs / 2 / HMACSHA512.cs
                        

                        
                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 

// 
// HMACSHA512.cs 
//
 
namespace System.Security.Cryptography {
    [System.Runtime.InteropServices.ComVisible(true)]
    public class HMACSHA512 : HMAC {
 
        private bool m_useLegacyBlockSize = Utils._ProduceLegacyHmacValues();
 
        // 
        // public constructors
        // 

        public HMACSHA512 () : this (Utils.GenerateRandom(128)) {}

        public HMACSHA512 (byte[] key) { 
            Utils._ShowLegacyHmacWarning();
 
            m_hashName = "SHA512"; 
            m_hash1 = new SHA512Managed();
            m_hash2 = new SHA512Managed(); 
            HashSizeValue = 512;
            BlockSizeValue = BlockSize;
            base.InitializeKey(key);
        } 

        private int BlockSize { 
            get { return m_useLegacyBlockSize ? 64 : 128; } 
        }
 
        /// 
        ///     In Whidbey we incorrectly used a block size of 64 bytes for HMAC-SHA-384 and HMAC-SHA-512,
        ///     rather than using the correct value of 128 bytes.  Setting this to true causes us to fall
        ///     back to the Whidbey mode which produces incorrect HMAC values. 
        ///
        ///     This value should be set only once, before hashing has begun, since we need to reset the key 
        ///     buffer for the block size change to take effect. 
        ///
        ///     The default vaue is off, however this can be toggled for the application by setting the 
        ///     legacyHMACMode config switch.
        ///
        ///     We will also produce a warning when using either of these classes which is output to the
        ///     debugger and event log unless the showLegacyHMACWarning config setting is disabled.  This 
        ///     warning is generated for the first time either class is constructed.
        ///  
        public bool ProduceLegacyHmacValues { 
            get { return m_useLegacyBlockSize; }
 
            set {
                m_useLegacyBlockSize = value;

                BlockSizeValue = BlockSize; 
                InitializeKey(KeyValue);
            } 
        } 
    }
}

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