Get-Hash.psm1

1. function Get-Hash { 
2. <# 
3. .SYNOPSIS 
4.    Creates a Hash of a file and prints the hash   
5. .DESCRIPTION 
6.     Uses System.Security.Cryptography.HashAlgorithm and members to create the hash 
7.     Also uses System.Text.AsciiEncoding to convert string to byte array. 
8.     Created as a Module. 
9. .NOTES 
10.     File Name  : Get-Hash.PSM1 
11.     Author     : Thomas Lee - tfl@psp.co.uk 
12.     Requires   : PowerShell V2 CTP3 
13.     Thanks to the #PowerShell Twitter Posse for help figuring out -verbose. 
14.     http://www.pshscripts.blogspot.com 
15.     Based on  
16.     http://tinyurl.com/aycszb written by Bart De Smet 
17. .PARAMETER Algorithm 
18.     The name of one of the hash Algorithms defined at 
19.     http://msdn.microsoft.com/en-us/library/system.security.cryptography.hashalgorithm.aspx 
20. .PARAMETER File 
21.     The name of a file to provide a hash for. 
22. .EXAMPLE 
23.     PS C:\foo> ls *.txt | where {!$_.psiscontainer}| Get-Hash sha1 -verbose:$true 
24.     OK - I'll be chatty 
25.  
26.     Processing C:\foo\asciifile.txt 
27.     sha1 hash of file C:\foo\asciifile.txt is "3529f51d2dd9c3c45e539eee5b42b07a8b74f9f5" 
28.  
29.     Processing C:\foo\log.txt 
30.     sha1 hash of file C:\foo\log.txt is "89dd3b94d3cb7f645498925e77346aa9218d7ffe" 
31.  
32.     Processing C:\foo\sites.txt 
33.     sha1 hash of file C:\foo\sites.txt is "2e434f1c2c16fc1060cd9f2e0226e142ea450ce4" 
34.  
35.     Processing C:\foo\test.txt 
36.     File C:\foo\test.txt can not be hashed 
37.  
38.     Processing C:\foo\test.txt.txt 
39.     File C:\foo\test.txt.txt can not be hashed 
    
40.  
41.     Processing C:\foo\test2.txt 
42.     File C:\foo\test2.txt can not be hashed 
43.  
44.     Processing C:\foo\unicodefile.txt 
45.     sha1 hash of file C:\foo\unicodefile.txt is "3529f51d2dd9c3c45e539eee5b42b07a8b74f9f5" 
46. .EXAMPLE 
47.     PS C:\foo> ls *.txt | where {!$_.psiscontainer}| Get-Hash sha1 
48.     3529f51d2dd9c3c45e539eee5b42b07a8b74f9f5 
49.     89dd3b94d3cb7f645498925e77346aa9218d7ffe 
50.     2e434f1c2c16fc1060cd9f2e0226e142ea450ce4 
51.     3529f51d2dd9c3c45e539eee5b42b07a8b74f9f5 
52. .EXAMPLE 
53.     PS C:\foo> Get-Hash  md5 asciifile.txt -verbose:$true 
54.     OK - I'll be chatty 
55.  
56.     Processing asciifile.txt 
57.     md5 hash of file asciifile.txt is "b5fe789f9d497f8022d47f620de25499" 
58. .EXAMPLE 
59.     PS C:\foo> Get-Hash  md5 asciifile.txt 
60.     b5fe789f9d497f8022d47f620de25499 
61. #> 
62. [CmdletBinding()] 
63. param ( 
64. [Parameter(Position=0, mandatory=$true)] 
65. [string] $Algorithm, 
66. [Parameter(Position=1, mandatory=$true, valuefrompipeline=$true)] 
67. [string] $File 
68. ) 
69.  
70. begin   { 
71. if ($VerbosePreference.Value__ -eq 0) {$verbose=$false} else {$verbose=$true} 
72. if ($verbose) {"OK - I'll be chatty";""} 
73. } 
74. process { 
75.     if ($verbose) {"Processing $file"} 
76.     $Algo=[System.Security.Cryptography.HashAlgorithm]::Create($algorithm) 
77.     if ($Algo){ 
78.         $Fc = Get-Content $File 
79.         if ($fc.count -gt 0) { 
80.             $Encoding = New-Object System.Text.ASCIIEncoding 
81.             $Bytes = $Encoding.GetBytes($fc)     
82.             # Now compute hash 
83.             $Hash = $Algo.ComputeHash($bytes)    
84.             $Hashstring ="" 
85.             foreach ($byte in $hash) {$hashstring += $byte.tostring("x2")} 
86.             # pass hash string on 
87.             if ($verbose){ 
88.               "{0} hash of file {1} is `"{2}`"" -f $algorithm, $file, $hashstring 
89.               "" 
90.             } 
91.             else { 
92.              $Hashstring 
93.             } 
94.         } 
95.         else { 
96.              if ($verbose) {"File {0} can not be hashed" -f $file ; ""}      
97.         }} 
98.     else { 
99.     "Algorithm {0} not found" -f $algorithm 
100.     } 
101. } # end process block 
102. } # End Function Definition 
103. Export-ModuleMember Get-hash 

Technorati Tags: PowerShell,Module,Security.Cryptography.HashAlgorithm,PowerShell V2

Share this post :