![]() Display whether or not the hash values are the same.Ĭonsole.WriteLine("The hash codes match.") Ĭonsole.WriteLine("The hash codes do not match.") Compare the values of the two byte arrays.īool same = sentHashValue.SequenceEqual(compareHashValue) This is the string that corresponds to the previous hash value.īyte compareHashValue = SHA256.HashData(messageBytes) This hash value is produced from "This is the original message!"īyte sentHashValue = Convert.FromHexString("67A1790DCA55B8803AD024EE28F616A284DF5DD7B8BA5F68B4B252A5E925AF79") The following example compares the previous hash value of a string to a new hash value. For this system to work, the protected hash must be encrypted or kept secret from all untrusted parties. If the values do not match, the data has been corrupted. If the hash values match, the data has not been altered. At a later time, the data can be hashed again and compared to the protected value. Usually, data is hashed at a certain time and the hash value is protected in some way. This code will display the following string to the console: 67A1790DCA55B8803AD024EE28F616A284DF5DD7B8BA5F68B4B252A5E925AF79ĭata can be compared to a hash value to determine its integrity. 'Create the hash value from the array of bytes.ĭim hashValue As Byte() = SHA256.HashData(messageBytes)Ĭonsole.WriteLine(Convert.ToHexString(hashValue)) 'Convert the string into an array of bytes.ĭim messageBytes As Byte() = (messageString) Create the hash value from the array of bytes.īyte hashValue = SHA256.HashData(messageBytes) Ĭonsole.WriteLine(Convert.ToHexString(hashValue)) ĭim messageString As String = "This is the original message!" Convert the string into an array of bytes.īyte messageBytes = (messageString) String messageString = "This is the original message!" The hash value is then displayed to the console. The example uses Encoding.UTF8 to convert the string into an array of bytes that are hashed by using the SHA256 class. The following example uses the SHA-256 hash algorithm to create a hash value for a string. The hash classes can hash either an array of bytes or a stream object. ![]() This topic describes how to generate and verify hash codes by using the classes in the namespace. ![]() The hash value of received data can be compared to the hash value of data as it was sent to determine whether the data was altered. Hash values are also useful for verifying the integrity of data sent through insecure channels. You can sign a hash value more efficiently than signing the larger value. Hash values represent large amounts of data as much smaller numeric values, so they are used with digital signatures. A hash value is a numeric value of a fixed length that uniquely identifies data.
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