GetStringHash.psm1
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#requires -Version 1 <# #> Function Get-StringHash {<# .SYNOPSIS Similar to Get-FileHash, computes the hash value for a string by using a specified hash algorithm. .DESCRIPTION Get-StringHash computes the hash value for a string by using a specified hash algorithm. A hash value is a unique value that corresponds to the characters of the string. The purpose of hash values is to provide a cryptographically consistent and reliable way to summarize or abstract a string by using a seemingly random token. While some hash algorithms, including MD5 and SHA1, are no longer considered secure, they still useful, and somewhat common mechanisms to generate summary hashes/token values for other, more complex data elements. By default, the Get-StringHash cmdlet uses the SHA256 algorithm, although all hash algorithms that are also supported by Get-FileHash cmdlet can be used. .PARAMETER String String to be encoded through the hash function / algorithm .PARAMETER Algorithm Specifies the cryptographic hash function to use for computing the hash value of the contents of the specified string. A cryptographic hash function includes the property that it is not possible to find two distinct inputs that generate the same hash values. Hash functions are commonly used with digital signatures and for data integrity. Valid values for this parameter are SHA1, SHA256, SHA384, SHA512, MACTripleDES, MD5, and RIPEMD160. If no value is specified, or if the parameter is omitted, the default value is SHA256. For security reasons, MD5 and SHA1, which are no longer considered secure, should only be used for simple change validation, and should not be used to generate hash values for strings that require protection from attack or tampering. MACTripleDES creates the shortest hash value string length .Example PS .\> Get-StringHash http://jongurgul.com/blog/get-stringhash-get-filehash/ | Format-List Algorithm : SHA256 Hash : a91e4392f788b8800b32c6bdc03db6385c373ff5983ba0a5b35f4babe9b4ec99 String : http://jongurgul.com/blog/get-stringhash-get-filehash/ This example uses the Get-StringHash cmdlet to compute the hash value for the URL for this function. The hash algorithm used is the default, SHA256. The output is piped to the Format-List cmdlet to format the output as a list. .Example PS .\> Get-StringHash -string "Treat your servers like cattle, not pets" -Algorithm MD5 Hash Algorithm String ---- --------- ------ 3ef0c0330b5602ad44f78a9ec38e0245 MD5 Treat your servers like cattle, not pets This command uses the Get-StringHash cmdlet and the MD5 algorithm to compute the hash value for one of my favorite quotes from Jeffrey Snover (@jsnover) .NOTES NAME : Get-StringHash VERSION : 1.1 LAST UPDATED : 12/1/2015 AUTHOR : Bryan Dady @bcdady Version History : 1.0 - create .psm1 script module from Get-StringHash code on TechNet Gallery. 1.1 - Update/refactor with ISESteroids and ISEScriptingGeek's 'Add Help' cmdlet .LINK https://gallery.technet.microsoft.com/scriptcenter/Get-StringHash-aa843f71 .LINK http://jongurgul.com/blog/get-stringhash-get-filehash/ .LINK .LINK PSLogger .INPUTS None .OUTPUTS None #> param ( [Parameter(Mandatory=$true, Position=0, ValueFromPipeline=$true, ValueFromPipelineByPropertyName=$true, HelpMessage='Specify string to be hashed. Accepts from pipeline.')] [alias('text','InputObject')] [ValidateNotNullOrEmpty()] [string] $String, [Parameter(Mandatory=$false, Position=1, ValueFromPipeline=$false, ValueFromPipelineByPropertyName=$false, HelpMessage='Specify string to be hashed. Accepts from pipeline.')] [alias('HashName')] [ValidateSet('SHA1', 'SHA256', 'SHA384', 'SHA512', 'MACTripleDES', 'MD5', 'RIPEMD160')] [string] $Algorithm = 'SHA256' ) $StringBuilder = New-Object -TypeName System.Text.StringBuilder [System.Security.Cryptography.HashAlgorithm]::Create($Algorithm).ComputeHash([System.Text.Encoding]::UTF8.GetBytes($String)) | ForEach-Object -Process { [Void]$StringBuilder.Append($_.ToString('x2')) } #'Optimize New-Object invocation, based on Don Jones' recommendation: https://technet.microsoft.com/en-us/magazine/hh750381.aspx $Private:properties = @{ 'Algorithm' = $Algorithm 'Hash' = $StringBuilder.ToString() 'String' = $String } $Private:RetObject = New-Object –TypeName PSObject –Prop $properties | Sort-Object return $RetObject } |