HMACSHA512.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / clr / src / BCL / System / Security / Cryptography / HMACSHA512.cs / 1305376 / 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)) {} 

        [System.Security.SecuritySafeCritical]  // auto-generated 
        public HMACSHA512 (byte[] key) { 
            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.
        /// 
        public bool ProduceLegacyHmacValues { 
            get { return m_useLegacyBlockSize; }
 
            set { 
                m_useLegacyBlockSize = value;
 
                BlockSizeValue = BlockSize;
                InitializeKey(KeyValue);
            }
        } 
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.

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