How to get an MD5 checksum in PowerShell

Question

I would like to calculate an MD5 checksum of some content  How do I do this in PowerShell

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PowerShell One-Liners  string to hash   MD5    System BitConverter   ToString  New-Object -TypeName System Security Cryptography MD5CryptoServiceProvider  ComputeHash  New-Object -TypeName System Text UTF8Encoding  GetBytes  Hello  World       Replace  -        SHA1    System BitConverter   ToString  New-Object -TypeName System Security Cryptography SHA1CryptoServiceProvider  ComputeHash  New-Object -TypeName System Text UTF8Encoding  GetBytes  Hello  World       Replace  -        SHA256    System BitConverter   ToString  New-Object -TypeName System Security Cryptography SHA256CryptoServiceProvider  ComputeHash  New-Object -TypeName System Text UTF8Encoding  GetBytes  Hello  World       Replace  -        SHA384    System BitConverter   ToString  New-Object -TypeName System Security Cryptography SHA384CryptoServiceProvider  ComputeHash  New-Object -TypeName System Text UTF8Encoding  GetBytes  Hello  World       Replace  -        SHA512    System BitConverter   ToString  New-Object -TypeName System Security Cryptography SHA512CryptoServiceProvider  ComputeHash  New-Object -TypeName System Text UTF8Encoding  GetBytes  Hello  World       Replace  -

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Here is the snippet that I am using to get the MD5 for a given string    text    text goes here      md5     Security Cryptography MD5CryptoServiceProvider   new    utf8    Text UTF8Encoding   UTF8  bytes   md5 ComputeHash  utf8 GetBytes  text    hash    string   Concat  bytes foreach    ToString  x2

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Sample for right-click menu option as well    HKEY CLASSES ROOT   shell SHA1 PS check command     C   Windows  system32  WindowsPowerShell  v1 0  powershell exe -NoExit -Command Get-FileHash -Algorithm SHA1   1

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This becomes a one-liner if you download File Checksum Integrity Verifier  FCIV  from Microsoft   I downloaded FCIV from here  Availability and description of the File Checksum Integrity Verifier utility  Run the following command  I had ten files to check   Get-ChildItem WTAM  tar        fciv    Name

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This will return an MD5 hash for a file on a remote computer   Invoke-Command -ComputerName RemoteComputerName -ScriptBlock        fullPath   Resolve-Path  c  Program Files Internet Explorer iexplore exe       md5   new-object -TypeName System Security Cryptography MD5CryptoServiceProvider      file    System IO File   OpenRead  fullPath       hash    System BitConverter   ToString  md5 ComputeHash  file        hash -replace  -           file Dispose

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If the content is a string    someString    Hello  World    md5   New-Object -TypeName System Security Cryptography MD5CryptoServiceProvider  utf8   New-Object -TypeName System Text UTF8Encoding  hash    System BitConverter   ToString  md5 ComputeHash  utf8 GetBytes  someString      If the content is a file    someFilePath    C  foo txt   md5   New-Object -TypeName System Security Cryptography MD5CryptoServiceProvider  hash    System BitConverter   ToString  md5 ComputeHash  System IO File   ReadAllBytes  someFilePath        Starting in PowerShell version 4  this is easy to do for files out of the box with the Get-FileHash cmdlet   Get-FileHash  lt filepath gt  -Algorithm MD5   This is certainly preferable since it avoids the problems the first solution offers as identified in the comments  uses a stream  closes it  and supports large files

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This site has an example  Using Powershell for MD5 Checksums  It uses the  NET framework to instantiate an instance of the MD5 hash algorithm to calculate the hash   Here s the code from the article  incorporating Stephen s comment   param      file     algo    System Security Cryptography HashAlgorithm   Create  MD5    stream   New-Object System IO FileStream  Path   System IO FileMode   Open       System IO FileAccess   Read    md5StringBuilder   New-Object System Text StringBuilder  algo ComputeHash  stream         void   md5StringBuilder Append    ToString  x2       md5StringBuilder ToString     stream Dispose

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This is what I use to get a consistent hash value   function New-CrcTable        uint32  c    null      crcTable   New-Object  System Uint32    256      for   n   0   n -lt 256   n               c    uint32  n         for   k   0   k -lt 8   k                  if   c -band 1                     c    0xEDB88320 -bxor   c -shr 1                             else                    c     c -shr 1                                   crcTable  n     c            Write-Output  crcTable    function Update-Crc   uint32  crc   byte    buffer   int  length   crcTable         uint32  c    crc      for   n   0   n -lt  length   n               c     crcTable   c -bxor  buffer  n   -band 0xFF   -bxor   c -shr 8             Write-Output  c    function Get-CRC32        lt            SYNOPSIS             Calculate CRC           DESCRIPTION             This function calculates the CRC of the input data using the CRC32 algorithm           EXAMPLE             Get-CRC32  data          EXAMPLE              data   Get-CRC32          NOTES             C to PowerShell conversion based on code in https   www w3 org TR PNG  D-CRCAppendix              Author    yvind Kallstad             Date  06 02 2017             Version  1 0          INPUTS             byte            OUTPUTS             uint32          LINK             https   communary net           LINK             https   www w3 org TR PNG  D-CRCAppendix        gt       CmdletBinding        param             Array of Bytes to use for CRC calculation          Parameter Position   0  ValueFromPipeline    true            ValidateNotNullOrEmpty             byte    InputObject             dataArray            crcTable   New-CrcTable     foreach   item  in  InputObject             dataArray     item            inputLength    dataArray Length     Write-Output   Update-Crc -crc 0xffffffffL -buffer  dataArray -length  inputLength -crcTable  crcTable  -bxor 0xffffffffL     function GetHash          CmdletBinding        param           Parameter Position   0  ValueFromPipeline    true            ValidateNotNullOrEmpty             string  InputString             bytes    System Text Encoding   UTF8 GetBytes  InputString       hasCode   Get-CRC32  bytes      hex     0 x   -f  hasCode     return  hex    function Get-FolderHash        CmdletBinding        param           Parameter Position   0  ValueFromPipeline    true            ValidateNotNullOrEmpty             string  FolderPath             FolderContent   New-Object System Collections ArrayList     Get-ChildItem  FolderPath -Recurse   Where-Object           if   System IO File   Exists                     FolderContent AddRange  System IO File   ReadAllBytes        Out-Null                       hasCode   Get-CRC32  FolderContent      hex     0 x   -f  hasCode     return  hex Substring 0  8  ToLower

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There are a lot of examples online using ComputeHash    My testing showed this was very slow when running over a network connection  The snippet below runs much faster for me  however your mileage may vary    md5    System Security Cryptography MD5   Create  MD5    fd    System IO File   OpenRead  file   buf   New-Object byte    1024 1024 8    8 MB buffer while    read len    fd Read  buf 0  buf length   -eq  buf length        total     buf length      md5 TransformBlock  buf  offset  buf length  buf  offset      Write-Progress -Activity  Hashing File           -Status  file -percentComplete   total  fd length   100       Finalize the last read  md5 TransformFinalBlock  buf  0   read len   hash    md5 Hash    Convert hash bytes to a hexadecimal formatted string  hash   foreach    hash txt       ToString  x2     Write-Host  hash txt

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Here is a one-line-command example with both computing the proper checksum of the file  like you just downloaded  and comparing it with the published checksum of the original   For instance  I wrote an example for downloadings from the Apache JMeter project  In this case you have    downloaded binary file checksum of the original which is published in file md5 as one string in the format       3a84491f10fb7b147101cf3926c4a855  apache-jmeter-4 0 zip   Then using this PowerShell command  you can verify the integrity of the downloaded file   PS C  Distr gt   Get-FileHash   apache-jmeter-4 0 zip -Algorithm MD5  Hash -eq  Get-Content   apache-jmeter-4 0 zip md5   Convert-String -Example  hash path hash     Output   True   Explanation   The first operand of -eq operator is a result of computing the checksum for the file    Get-FileHash   apache-jmeter-4 0 zip -Algorithm MD5  Hash   The second operand is the published checksum value  We firstly get content of the file md5 which is one string and then we extract the hash value based on the string format   Get-Content   apache-jmeter-4 0 zip md5   Convert-String -Example  hash path hash    Both file and file md5 must be in the same folder for this command work

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Here are the two lines  just change  hello  in line  2   PS C   gt   Reflection Assembly   LoadWithPartialName  System Web   PS C   gt   System Web Security FormsAuthentication   HashPasswordForStoringInConfigFile  hello    MD5

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Another built-in command that s long been installed in Windows by default dating back to 2003 is Certutil  which of course can be invoked from PowerShell  too   CertUtil -hashfile file foo MD5    Caveat  MD5 should be in all caps for maximum robustness

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There is now a Get-FileHash function which is very handy   PS C   gt  Get-FileHash C  Users Andris Downloads Contoso8 1 ENT iso -Algorithm SHA384   Format-List  Algorithm   SHA384 Hash        20AB1C2EE19FC96A7C66E33917D191A24E3CE9DAC99DB7C786ACCE31E559144FEAFC695C58E508E2EBBC9D3C96F21FA3 Path        C  Users Andris Downloads Contoso8 1 ENT iso   Just change SHA384 to MD5   The example is from the official documentation of PowerShell 5 1  The documentation has more examples

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Here s a function I use that handles relative and absolute paths   function md5hash  path         fullPath   Resolve-Path  path      md5   new-object -TypeName System Security Cryptography MD5CryptoServiceProvider      file    System IO File   Open  fullPath  System IO Filemode   Open   System IO FileAccess   Read      try            System BitConverter   ToString  md5 ComputeHash  file         finally            file Dispose             Thanks to  davor above for the suggestion to use Open   instead of ReadAllBytes   and to  jpmc26 for the suggestion to use a finally block

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If you are using the PowerShell Community Extensions there is a Get-Hash commandlet that will do this easily   C  PS gt   hello world    Get-Hash -Algorithm MD5   Algorithm  MD5   Path         HashString   E42B054623B3799CB71F0883900F2764

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Here is a pretty print example attempting to verify the SHA256 fingerprint  I downloaded gpg4win v3 0 3 using PowerShell v4  requires Get-FileHash    Download the package from https   www gpg4win org download html  open PowerShell  grab the hash from the download page  and run   cd   env USERPROFILE  Downloads  file    gpg4win-3 0 3 exe     Set  hash to the hash reference from the download page   hash    477f56212ee60cc74e0c5e5cc526cec52a069abff485c89c2d57d1b4b6a54971     If you have an MD5 hash     hashAlgo  MD5   hashAlgo    SHA256    computed hash    Get-FileHash -Algorithm  hashAlgo  file  Hash ToUpper   if   computed hash CompareTo  hash ToUpper    -eq 0         Write-Output  Hash matches for file  file      else        Write-Output   Hash DOES NOT match for file  0    nOriginal hash   1   nComputed hash   2   -f   file   hash ToUpper     computed hash        Output   Hash matches for file gpg4win-3 0 3 exe

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As stated in the accepted answer  Get-FileHash is easy to use with files  but it is also possible to use it with strings    s    asdf  Get-FileHash -InputStream   System IO MemoryStream   New  System Text Encoding   ASCII GetBytes  s

[powershell] How to get an MD5 checksum in PowerShell

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