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ConvertTo-SecureString

  • Reference
Module:
Microsoft.PowerShell.Security

Converts plain text or encrypted strings to secure strings.

Syntax

ConvertTo-SecureString
              [-String] <String>
              [[-SecureKey] <SecureString>]
              [<CommonParameters>]
ConvertTo-SecureString
              [-String] <String>
              [-AsPlainText]
              [-Force]
              [<CommonParameters>]
ConvertTo-SecureString
              [-String] <String>
              [-Key <Byte[]>]
              [<CommonParameters>]

Description

The ConvertTo-SecureString cmdlet converts encrypted standard strings into secure strings. It can also convert plain text to secure strings. It is used with ConvertFrom-SecureString and Read-Host. The secure string created by the cmdlet can be used with cmdlets or functions that require a parameter of type SecureString. The secure string can be converted back to an encrypted, standard string using the ConvertFrom-SecureString cmdlet. This enables it to be stored in a file for later use.

If the standard string being converted was encrypted with ConvertFrom-SecureString using a specified key, that same key must be provided as the value of the Key or SecureKey parameter of the ConvertTo-SecureString cmdlet.

Note

Note that per DotNet, the contents of a SecureString are not encrypted on non-Windows systems.

Examples

Example 1: Convert a secure string to an encrypted string

This example shows how to create a secure string from user input, convert the secure string to an encrypted standard string, and then convert the encrypted standard string back to a secure string.

PS C:\> $Secure = Read-Host -AsSecureString
PS C:\> $Secure
System.Security.SecureString
PS C:\> $Encrypted = ConvertFrom-SecureString -SecureString $Secure
PS C:\> $Encrypted
01000000d08c9ddf0115d1118c7a00c04fc297eb010000001a114d45b8dd3f4aa11ad7c0abdae98000000000
02000000000003660000a8000000100000005df63cea84bfb7d70bd6842e7efa79820000000004800000a000
000010000000f10cd0f4a99a8d5814d94e0687d7430b100000008bf11f1960158405b2779613e9352c6d1400
0000e6b7bf46a9d485ff211b9b2a2df3bd6eb67aae41
PS C:\> $Secure2 = ConvertTo-SecureString -String $Encrypted
PS C:\> $Secure2
System.Security.SecureString

The first command uses the AsSecureString parameter of the Read-Host cmdlet to create a secure string. After you enter the command, any characters that you type are converted into a secure string and then saved in the $Secure variable.

The second command displays the contents of the $Secure variable. Because the $Secure variable contains a secure string, PowerShell displays only the System.Security.SecureString type.

The third command uses the ConvertFrom-SecureString cmdlet to convert the secure string in the $Secure variable into an encrypted standard string. It saves the result in the $Encrypted variable.

The fourth command displays the encrypted string in the value of the $Encrypted variable.

The fifth command uses the ConvertTo-SecureString cmdlet to convert the encrypted standard string in the $Encrypted variable back into a secure string. It saves the result in the $Secure2 variable. The sixth command displays the value of the $Secure2 variable. The SecureString type indicates that the command was successful.

Example 2: Create a secure string from an encrypted string in a file

This example shows how to create a secure string from an encrypted standard string that is saved in a file.

$Secure = Read-Host -AsSecureString
$Encrypted = ConvertFrom-SecureString -SecureString $Secure -Key (1..16)
$Encrypted | Set-Content Encrypted.txt
$Secure2 = Get-Content Encrypted.txt | ConvertTo-SecureString -Key (1..16)

The first command uses the AsSecureString parameter of the Read-Host cmdlet to create a secure string. After you enter the command, any characters that you type are converted into a secure string and then saved in the $Secure variable.

The second command uses the ConvertFrom-SecureString cmdlet to convert the secure string in the $Secure variable into an encrypted standard string by using the specified key. The contents are saved in the $Encrypted variable.

The third command uses a pipeline operator (|) to send the value of the $Encrypted variable to the Set-Content cmdlet, which saves the value in the Encrypted.txt file.

The fourth command uses the Get-Content cmdlet to get the encrypted standard string in the Encrypted.txt file. The command uses a pipeline operator to send the encrypted string to the ConvertTo-SecureString cmdlet, which converts it to a secure string by using the specified key. The results are saved in the $Secure2 variable.

Example 3: Convert a plain text string to a secure string

This command converts the plain text string P@ssW0rD! into a secure string and stores the result in the $Secure_String_Pwd variable.

Starting in PowerShell 7, the Force parameter is not required when using the AsPlainText parameter. However, including the Force parameter ensures the statement is compatible with earlier versions.

$Secure_String_Pwd = ConvertTo-SecureString "P@ssW0rD!" -AsPlainText -Force

Caution

You should avoid using plain text strings in script or from the command line. The plain text can show up in event logs and command history logs.

Parameters

-AsPlainText

Specifies a plain text string to convert to a secure string. The secure string cmdlets help protect confidential text. The text is encrypted for privacy and is deleted from computer memory after it is used. If you use this parameter to provide plain text as input, the system cannot protect that input in this manner.

Type:SwitchParameter
Position:1
Default value:None
Required:False
Accept pipeline input:False
Accept wildcard characters:False

-Force

Beginning in PowerShell 7, The Force parameter is no longer required when using the AsPlainText parameter. While the parameter is not used, it was not removed to provide compatibility with earlier versions of PowerShell.

Type:SwitchParameter
Position:2
Default value:None
Required:False
Accept pipeline input:False
Accept wildcard characters:False

-Key

Specifies the encryption key used to convert the original secure string into the encrypted standard string. Valid key lengths are 16, 24 and 32 bytes.

Type:Byte[]
Position:Named
Default value:None
Required:False
Accept pipeline input:False
Accept wildcard characters:False

-SecureKey

Specifies the encryption key used to convert the original secure string into the encrypted standard string. The key must be provided in the format of a secure string. The secure string will be converted to a byte array to be used as the key. Valid secure key lengths are 8, 12 and 16 code points.

Type:SecureString
Position:1
Default value:None
Required:False
Accept pipeline input:False
Accept wildcard characters:False

-String

Specifies the string to convert to a secure string.

Type:String
Position:0
Default value:None
Required:True
Accept pipeline input:True
Accept wildcard characters:False

Inputs

String

You can pipe a standard encrypted string to ConvertTo-SecureString.

Outputs

SecureString

ConvertTo-SecureString returns a SecureString object.

Notes

Some characters, such as emoticons, correspond to several code points in the string that contains them. Avoid using these characters because they may cause problems and misunderstandings when used in a password.