Class Helpers

Helper methods to ease interaction with Web API 3. These methods require .NET Framework 4.0 or 4.6.

Inheritance
object
Helpers
Inherited Members
Namespace: SKMV3Methods
Assembly: Cryptolens.Licensing.CrossPlatform.dll
Syntax
public static class Helpers

Properties

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WindowsOnly

Only set this setting if you plan to target Windows only. It's only necessary in rare cases. If you have any questions, please contact [email protected].

Declaration
public static bool WindowsOnly { get; set; }
Property Value
Type Description
bool

Methods

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ComputePasswordHash(string)

Computes a string hash of a password using PBKDF2. Note, in comparison to using hash algorithms such as SHA256, the algorithm used in this method slows down the computation on purpose, to make sure it is harder to guess the original password.

Declaration
public static string ComputePasswordHash(string password)
Parameters
Type Name Description
string password
Returns
Type Description
string
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ComputePasswordHash(string, byte[])

Computes a string hash of a password using PBKDF2. Note, in comparison to using hash algorithms such as SHA256, the algorithm used in this method slows down the computation on purpose, to make sure it is harder to guess the original password.

Declaration
public static string ComputePasswordHash(string password, byte[] salt = null)
Parameters
Type Name Description
string password
System.Byte salt
Returns
Type Description
string
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GetAssemblyHash()

Computes the method of the entry assembly. This method is intended to be called from an SDK that you want to protect. The "Entry Assembly" is the first assembly that leads to a method being called in your SDK.

Normally, if a customer uses your SDK in an assembly A, this method will compute the hash/fingerprint of that assembly. If they have developed two assemblies, where the A uses B and B uses your SDK (which calls this method), i.e. A -> B -> SDK, then the hash is computed of the first assembly, i.e. A.

Declaration
public static AssemblySignature GetAssemblyHash()
Returns
Type Description
AssemblySignature

An AssemblySignature or null if the file cannot be found and/or cannot be read.
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GetAssemblyHash(string)

Computes the method of the entry assembly. This method is intended to be called from an SDK that you want to protect. The "Entry Assembly" is the first assembly that leads to a method being called in your SDK.

Normally, if a customer uses your SDK in an assembly A, this method will compute the hash/fingerprint of that assembly. If they have developed two assemblies, where the A uses B and B uses your SDK (which calls this method), i.e. A -> B -> SDK, then the hash is computed of the first assembly, i.e. A.

Declaration
public static AssemblySignature GetAssemblyHash(string path)
Parameters
Type Name Description
string path

Allows you to specify a custom path of the assembly to sign. If null, the default assembly will be signed, as described in the summary.
Returns
Type Description
AssemblySignature

An AssemblySignature or null if the file cannot be found and/or cannot be read.
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GetFloatingLicenseInformation(ActivateModel, KeyInfoResult)

Returns floating license related information.

Declaration
public static FloatingLicenseInformation GetFloatingLicenseInformation(ActivateModel activationModel, KeyInfoResult activationResult)
Parameters
Type Name Description
ActivateModel activationModel
KeyInfoResult activationResult
Returns
Type Description
FloatingLicenseInformation
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GetFloatingLicenseInformation(int, int, int)

Returns floating license related information.

Declaration
public static FloatingLicenseInformation GetFloatingLicenseInformation(int MaxOverdraft, int MaxNoOfMachines, int UsedFloatingMachines)
Parameters
Type Name Description
int MaxOverdraft
int MaxNoOfMachines
int UsedFloatingMachines
Returns
Type Description
FloatingLicenseInformation
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GetHardiskId()

An alternative way to compute the machine code by relying on the Hardisk Id (assigned by the manufacturer). This is different from Volume Id. Please note: although based on our testing, it should run without admin access, this might not be the case on some machines. Furthermore, this method is specific to Windows and cannot be used on other platforms.

Declaration
public static string GetHardiskId()
Returns
Type Description
string
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GetMACAddress()

Computes the MAC address, which can be used as a way to identify a machine uniquely.

Declaration
public static string GetMACAddress()
Returns
Type Description
string
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GetMachineCode(bool, int)

Returns the machine code of the current device with SHA-256 as the hash function. This method works differently depending on the binaries that you use. By default, machine code is computed using COM, which requires System.Management. This is only supported on Windows, it's better to set platformIndependent=true. If you use a version of library without System.Management, the platform independent machine code will be computed by default.

The supported platforms are Windows, Mac and Linux. Note, sudo access is required if Linux is used.

In newer projects, we recommend to always set platformIndependent=true or use GetMachineCodePI().

If version is set to 2, you can get the machine code as in the Python client, assuming similar settings are used. You can read more about it here: https://help.cryptolens.io/faq/index#machine-code-generation

Declaration
public static string GetMachineCode(bool platformIndependent = false, int v = 1)
Parameters
Type Name Description
bool platformIndependent
int v
Returns
Type Description
string
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GetMachineCodePI()

Computes a platform independent machine code that works on Windows, Linux and Mac and does not require System.Management.

Note: On Linux, sudo access is necessary.

Declaration
public static string GetMachineCodePI()
Returns
Type Description
string
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GetMachineCodePI(int)

Computes a platform independent machine code that works on Windows, Linux and Mac and does not require System.Management.

Note: On Linux, sudo access is necessary.

If version is set to 2, you can get the machine code as in the Python client, assuming similar settings are used. You can read more about it here: https://help.cryptolens.io/faq/index#machine-code-generation

Declaration
public static string GetMachineCodePI(int v = 1)
Parameters
Type Name Description
int v
Returns
Type Description
string
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GetOSStats()

Creates a JSON dictionary of the type MachineInfo, which contains OSVersion, OSName and Is64Bit (not available in NET 3.5).

Declaration
public static string GetOSStats()
Returns
Type Description
string

A string representation of the JSON dictionary.
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GetPlatform()

Declaration
public static Helpers.OSType GetPlatform()
Returns
Type Description
HelpersOSType
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HasFeature(LicenseKey, int)

Checks so that a certain Feature is enabled (i.e. it's set to TRUE).

Declaration
public static bool HasFeature(LicenseKey licenseKey, int featureNumber)
Parameters
Type Name Description
LicenseKey licenseKey
int featureNumber

The feature number, eg. feature1, feature 2, etc. FeatureNumber can be 1,2,...,8.
Returns
Type Description
bool

A key information object if the condition is satisfied. Null otherwise.
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HasFeature(LicenseKey, string)

Uses a special data object associated with the license key to determine if a certain feature exists (instead of the 8 feature flags).

Formatting: The name of the data object should be 'cryptolens_features' and it should be structured as a JSON array.

For example,

["f1", "f2"]

means f1 and f2 are true. You can also have feature bundling, eg. 

["f1", ["f2",["voice","image"]]]

which means that f1 and f2 are true, as well as f2.voice and f2.image. You can set any depth, eg. you can have

["f1", ["f2",[["voice",["all"]], "image"]]]

means f2.voice.all is true as well as f2.voice and f2. The dots symbol is used to specify the "sub-features".

Read more here: https://help.cryptolens.io/web-interface/feature-templates

Declaration
public static bool HasFeature(LicenseKey licenseKey, string featureName)
Parameters
Type Name Description
LicenseKey licenseKey

The license key
string featureName

For example, "f2.voice.all".
Returns
Type Description
bool
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IsOnRightMachine(LicenseKey, bool, bool, bool)

Checks if the current license key is on the correct device with SHA-256 as the hash function.

Declaration
public static bool IsOnRightMachine(LicenseKey licenseKey, bool isFloatingLicense = false, bool allowOverdraft = false, bool platformIndependent = false)
Parameters
Type Name Description
LicenseKey licenseKey

The license key object.
bool isFloatingLicense

If this is a floating license, this parameter has to be set to true. You can enable floating licenses by setting FloatingTimeInterval to a value greater than 0.
bool allowOverdraft

If floating licensing is enabled with overdraft, this parameter should be set to true. You can enable overdraft by setting MaxOverdraft to a value greater than 0.
bool platformIndependent

Allows you to specify if you want to use the old machine code method that is based on COM and requires System.Management or use the new platform independent method, i.e. GetMachineCodePI().
Returns
Type Description
bool
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IsOnRightMachine(LicenseKey, string, bool, bool)

Checks if the current license key is on the correct device with SHA-256 as the hash function.

Declaration
public static bool IsOnRightMachine(LicenseKey licenseKey, string machineCode, bool isFloatingLicense = false, bool allowOverdraft = false)
Parameters
Type Name Description
LicenseKey licenseKey

The license key object.
string machineCode

A unique identifier of the machine.
bool isFloatingLicense

If this is a floating license, this parameter has to be set to true. You can enable floating licenses by setting FloatingTimeInterval to a value greater than 0.
bool allowOverdraft

If floating licensing is enabled with overdraft, this parameter should be set to true. You can enable overdraft by setting MaxOverdraft to a value greater than 0.
Returns
Type Description
bool
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IsOnRightMachinePI(LicenseKey, bool, bool, int)

Checks if the current license key is on the correct device with SHA-256 as the hash function.

Declaration
public static bool IsOnRightMachinePI(LicenseKey licenseKey, bool isFloatingLicense = false, bool allowOverdraft = false, int v = 1)
Parameters
Type Name Description
LicenseKey licenseKey

The license key object.
bool isFloatingLicense

If this is a floating license, this parameter has to be set to true. You can enable floating licenses by setting FloatingTimeInterval to a value greater than 0.
bool allowOverdraft

If floating licensing is enabled with overdraft, this parameter should be set to true. You can enable overdraft by setting MaxOverdraft to a value greater than 0.
int v

If version is set to 2, you can get the machine code as in the Python client, assuming similar settings are used. You can read more about it here: https://help.cryptolens.io/faq/index#machine-code-generation
Returns
Type Description
bool
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IsSuccessful(BasicResult)

Checks if the result obtained from an API call is successful.

Declaration
public static bool IsSuccessful(BasicResult result)
Parameters
Type Name Description
BasicResult result
Returns
Type Description
bool
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IsVM()

This method can help to detect if the application is running inside a virtual machine. It has been tested in Microsoft Hyper-V. Support for other VM applications is coming soon.

Declaration
public static bool IsVM()
Returns
Type Description
bool
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VerifyPassword(LicenseKey, string, string)

This method verifies the username and password with the information in the LicenseKey object. It provides a way to activate a license on a per user rather than per machine basis. To compute the password, the ComputePasswordHash(string) is used. A tutorial on how everything can be set up is available here: https://help.cryptolens.io/licensing-models/user-based-activations

Declaration
public static bool VerifyPassword(LicenseKey license, string username, string password)
Parameters
Type Name Description
LicenseKey license
string username
string password
Returns
Type Description
bool
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VerifySDKLicenseCertificate(string)

Verifies that the certificate of the software using the SDK is valid. This method will use GetAssemblyHash() to compute the hash of the assembly. The entry assembly will be verified, in other words, the assembly that initiated the call first.

Declaration
public static LicenseKey VerifySDKLicenseCertificate(string RSAPubKey)
Parameters
Type Name Description
string RSAPubKey

Your RSA Public Key, which can be found here: https://app.cryptolens.io/docs/api/v3/QuickStart
Returns
Type Description
LicenseKey

License Key object if the certificate is valid and null otherwise.
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VerifySDKLicenseCertificate(string, string, string)

Verifies that the certificate of the software using the SDK is valid. This method will use GetAssemblyHash() to compute the hash of the assembly. The entry assembly will be verified, in other words, the assembly that initiated the call first.

Declaration
public static LicenseKey VerifySDKLicenseCertificate(string RSAPubKey, string certificate, string path)
Parameters
Type Name Description
string RSAPubKey

Your RSA Public Key, which can be found here: https://app.cryptolens.io/docs/api/v3/QuickStart
string certificate

The name of the certificate. Do not add .skm extension, it will be added automatically.
string path

The path to the certificate and the assembly, whose hash is signed. Note, they need to be in the same folder.
Returns
Type Description
LicenseKey

License Key object if the certificate is valid and null otherwise.