Class CryptographyHelper

Provides helper methods to work with cryptographic service provider API.

Inheritance

System.Object

CryptographyHelper

Inherited Members

System.Object.ToString()

System.Object.Equals(System.Object)

System.Object.Equals(System.Object, System.Object)

System.Object.ReferenceEquals(System.Object, System.Object)

System.Object.GetHashCode()

System.Object.GetType()

System.Object.MemberwiseClone()

Namespace: Nevatech.Vsb.Repository.Security.Cryptography

Assembly: Nevatech.Vsb.Repository.dll

Syntax

public static class CryptographyHelper

Fields

Random

An initialized instance of the pseudo-random number generator.

Declaration

public static readonly Random Random

Field Value

Type	Description
System.Random

Methods

BytesToString(Byte[])

Converts string to array of bytes using UTF-8 encoding.

Declaration

public static string BytesToString(byte[] value)

Parameters

Type	Name	Description
System.Byte[]	value	Array of bytes to be converted.

Returns

Type	Description
System.String	Bytes representing original string.

BytesToString(Byte[], Int32, Int32, String, String)

Returns string representation of byte-array using specified format string that applied to each byte in array.

Declaration

public static string BytesToString(byte[] value, int index, int length, string formatString, string separator)

Parameters

Type	Name	Description
System.Byte[]	value	Array of bytes to be printed.
System.Int32	index	Index of the first byte to print.
System.Int32	length	Max number of bytes to print, or 0 to print all bytes.
System.String	formatString	Format string that will be applied to each byte in array.
System.String	separator	String that will be added between subsequent bytes (may be Null or empty).

Returns

Type	Description
System.String	String representation of byte-array.

CompareArrays(Byte[], Byte[])

Compares values in two provided arrays of bytes.

Declaration

public static bool CompareArrays(byte[] arrayA, byte[] arrayB)

Parameters

Type	Name	Description
System.Byte[]	arrayA	First array to compare with.
System.Byte[]	arrayB	Second array to compare with.

Returns

Type	Description
System.Boolean	True, if arrays are equal or Null. False, otherwise.

ComputeHash(String)

Computes hash value of provided string. Method automatically generates entropy value and prepend it to the result. Use ValidateHash(String, Byte[]) overload to check hash value generated by this method.

Declaration

public static byte[] ComputeHash(string value)

Parameters

Type	Name	Description
System.String	value	String that hash value needs to be calculated for.

Returns

Type	Description
System.Byte[]	Calculated hash value with prepended salt value.

Remarks

Method uses 4 bytes of entropy and SHA1 function for hash computation and results to 24 bytes value.

ComputeHash(String, Byte[])

Computes hash value of provided string with prepended salt value.

Declaration

public static byte[] ComputeHash(string value, byte[] salt)

Parameters

Type	Name	Description
System.String	value	String that hash value needs to be calculated for.
System.Byte[]	salt	Random set of bytes (optional).

Returns

Type	Description
System.Byte[]	Calculated hash value.

Remarks

Method uses SHA1 function for hash computation which results to 20 bytes value.

ComputeHash(String, Int32)

Computes hash value of provided string with prepended salt value.

Declaration

public static byte[] ComputeHash(string value, int salt)

Parameters

Type	Name	Description
System.String	value	String that hash value needs to be calculated for.
System.Int32	salt	Random integer value.

Returns

Type	Description
System.Byte[]	Calculated hash value.

Remarks

Method uses SHA1 function for hash computation which results to 20 bytes value.

ComputeHash(String, String)

Computes hash value of the provided string using the specified hashing algorithm.

Declaration

public static string ComputeHash(string value, string hashName)

Parameters

Type	Name	Description
System.String	value	String to be hashed.
System.String	hashName	The hash algorithm implementation to use: SHA1, SHA256, SHA384, SHA512, or MD5.

Returns

Type	Description
System.String	Base64-encoded hash value of the provided string.

CreateSalt()

Creates random cryptographically strong integer value.

Declaration

public static int CreateSalt()

Returns

Type	Description
System.Int32	Random cryptographically strong integer value.

CreateSalt(Int32)

Creates array of bytes filled with cryptographically strong sequence of random values.

Declaration

public static byte[] CreateSalt(int size)

Parameters

Type	Name	Description
System.Int32	size	Number of bytes to generate.

Returns

Type	Description
System.Byte[]	Array of size bytes filled with cryptographically strong sequence of random values.

CreateSignature(Byte[], Byte[])

Computes and returns digital signature value using provided data and private key.

Declaration

public static byte[] CreateSignature(byte[] data, byte[] privateKey)

Parameters

Type	Name	Description
System.Byte[]	data	Data to be signed.
System.Byte[]	privateKey	Public and private key pair which will be used to sign data.

Returns

Type	Description
System.Byte[]	Array of bytes that contains signature value.

DecryptToBytes(Byte[])

Decrypts provided data using Windows Data Protection API.

Declaration

public static byte[] DecryptToBytes(byte[] data)

Parameters

Type	Name	Description
System.Byte[]	data	Encrypted data.

Returns

Type	Description
System.Byte[]	Decrypted data.

DecryptToBytes(String)

Decrypts provided base64 string using Windows Data Protection API.

Declaration

public static byte[] DecryptToBytes(string value)

Parameters

Type	Name	Description
System.String	value	Base64 encoded encrypted data.

Returns

Type	Description
System.Byte[]	Decrypted data.

DecryptToString(Byte[])

Decrypts provided data using Windows Data Protection API and returns decrypted string.

Declaration

public static string DecryptToString(byte[] data)

Parameters

Type	Name	Description
System.Byte[]	data	Encrypted data.

Returns

Type	Description
System.String	Decrypted string.

DecryptToString(String)

Decrypts provided base64 string using Windows Data Protection API and returns decrypted string.

Declaration

public static string DecryptToString(string value)

Parameters

Type	Name	Description
System.String	value	Base64 encoded encrypted data.

Returns

Type	Description
System.String	Decrypted string.

DecryptWithCertificate(String, X509Certificate2)

Decrypts the encrypted base64-encoded text with the RSA private key stored in the provided X.509 certificate.

Declaration

public static string DecryptWithCertificate(string encryptedText, X509Certificate2 certificate)

Parameters

Type	Name	Description
System.String	encryptedText	The base64-encoded encrypted text to decrypt.
System.Security.Cryptography.X509Certificates.X509Certificate2	certificate	X.509 certificate to be used for asymmetrical encryption.

Returns

Type	Description
System.String	A decrypted plain text.

Exceptions

Type	Condition
System.ArgumentNullException	Thrown if the specified encryptedText or certificate argument is null.

DecryptWithPassword(Byte[], String)

Decrypts encrypted data with a password using AES algorithm.

Declaration

public static byte[] DecryptWithPassword(byte[] encryptedData, string password)

Parameters

Type	Name	Description
System.Byte[]	encryptedData	The encrypted data to decrypt.
System.String	password	The password to decrypt with.

Returns

Type	Description
System.Byte[]	A byte array that contains decrypted data.

Exceptions

Type	Condition
System.ArgumentNullException	Thrown if the specified encryptedData or password is null.

DecryptWithPassword(String, String)

Decrypts the encrypted base64-encoded text with a password using AES algorithm.

Declaration

public static string DecryptWithPassword(string encryptedText, string password)

Parameters

Type	Name	Description
System.String	encryptedText	The base64-encoded encrypted text to decrypt.
System.String	password	The password to decrypt with.

Returns

Type	Description
System.String	A decrypted plain text.

Exceptions

Type	Condition
System.ArgumentNullException	Thrown if the specified encryptedText or password is null.

EncryptToBytes(Byte[])

Encrypts provided data using Windows Data Protection API.

Declaration

public static byte[] EncryptToBytes(byte[] data)

Parameters

Type	Name	Description
System.Byte[]	data	Data to be encrypted.

Returns

Type	Description
System.Byte[]	Encrypted data.

EncryptToBytes(String)

Encrypts provided string using Windows Data Protection API.

Declaration

public static byte[] EncryptToBytes(string value)

Parameters

Type	Name	Description
System.String	value	String to be encrypted.

Returns

Type	Description
System.Byte[]	Encrypted data.

EncryptToString(Byte[])

Encrypts provided data using Windows Data Protection API and returns encrypted data as base64 string.

Declaration

public static string EncryptToString(byte[] data)

Parameters

Type	Name	Description
System.Byte[]	data	Data to be encrypted.

Returns

Type	Description
System.String	Encrypted data encoded with Base 64 digits.

EncryptToString(String)

Encrypts provided string using Windows Data Protection API and returns encrypted data as base64 string.

Declaration

public static string EncryptToString(string value)

Parameters

Type	Name	Description
System.String	value	String to be encrypted.

Returns

Type	Description
System.String	Encrypted data encoded with Base 64 digits.

EncryptWithCertificate(String, X509Certificate2)

Encrypts the provided text with the RSA public key stored in the provided X.509 certificate.

Declaration

public static string EncryptWithCertificate(string plainText, X509Certificate2 certificate)

Parameters

Type	Name	Description
System.String	plainText	The text to encrypt.
System.Security.Cryptography.X509Certificates.X509Certificate2	certificate	X.509 certificate to be used for asymmetrical encryption.

Returns

Type	Description
System.String	An encrypted, base64-encoded string.

Exceptions

Type	Condition
System.ArgumentNullException	Thrown if the specified plainText or certificate argument is null.

EncryptWithPassword(Byte[], String)

Encrypts data with a password using AES algorithm.

Declaration

public static byte[] EncryptWithPassword(byte[] data, string password)

Parameters

Type	Name	Description
System.Byte[]	data	The data to encrypt.
System.String	password	The password to encrypt with.

Returns

Type	Description
System.Byte[]	A byte array that contains encrypted data.

Exceptions

Type	Condition
System.ArgumentNullException	Thrown if the specified data or password is null or empty.

EncryptWithPassword(String, String)

Encrypts plain text with a password using AES algorithm.

Declaration

public static string EncryptWithPassword(string plainText, string password)

Parameters

Type	Name	Description
System.String	plainText	The text to encrypt.
System.String	password	The password to encrypt with.

Returns

Type	Description
System.String	An encrypted base64-encoded string.

Exceptions

Type	Condition
System.ArgumentNullException	Thrown if the specified plainText or password argument is null.

GenerateSecret(SecretType, Int32)

Randomly generates a secret of the specified length.

Declaration

public static string GenerateSecret(SecretType secretType, int length)

Parameters

Type	Name	Description
SecretType	secretType	Type of the generated secret. Binary secret is returned as a base64-encoded string.
System.Int32	length	For binary secret: the number of generated bytes. For password: the password length in chars. For token and captcha: the number of characters.

Returns

Type	Description
System.String	Password or base64-encoded binary secret.

StringToBytes(String)

Converts array of bytes to string using UTF-8 encoding.

Declaration

public static byte[] StringToBytes(string value)

Parameters

Type	Name	Description
System.String	value	Bytes to be decoded.

Returns

Type	Description
System.Byte[]	String that was encoded.

ToSecureString(String)

Converts provided string to System.Security.SecureString.

Declaration

public static SecureString ToSecureString(string value)

Parameters

Type	Name	Description
System.String	value	String to be converted.

Returns

Type	Description
System.Security.SecureString	System.Security.SecureString initialized from provided value, or Null if provided value was Null.

ValidateHash(String, Byte[])

Compares provided hash value with computed hash value for specified string. Parameter hash should also include prepended salt value that was originally used for hash calculation. Use this method to validate hash value calculated by ComputeHash(String) overload.

Declaration

public static bool ValidateHash(string value, byte[] hash)

Parameters

Type	Name	Description
System.String	value	String value to be validated.
System.Byte[]	hash	Hash value with prepended salt value calculated for provided value.

Returns

Type	Description
System.Boolean	True, if provided hash and salt correspond to specified value. False, otherwise.

ValidateHash(String, Byte[], Byte[])

Compares provided hash value with computed hash value for specified string with prepended salt value.

Declaration

public static bool ValidateHash(string value, byte[] hash, byte[] salt)

Parameters

Type	Name	Description
System.String	value	String value to be validated.
System.Byte[]	hash	Calculated hash for provided value and salt.
System.Byte[]	salt	Random set of bytes that was used to calculate hash value.

Returns

Type	Description
System.Boolean	True, if provided hash and salt correspond to specified value. False, otherwise.

ValidateHash(String, Byte[], Int32)

Compares provided hash value with computed hash value for specified string with prepended salt value.

Declaration

public static bool ValidateHash(string value, byte[] hash, int salt)

Parameters

Type	Name	Description
System.String	value	String value to be validated.
System.Byte[]	hash	Calculated hash for provided value and salt.
System.Int32	salt	Random integer value.

Returns

Type	Description
System.Boolean	True, if provided hash and salt correspond to specified value. False, otherwise.

VerifySignature(Byte[], Byte[], Byte[])

Verifies that provided binary data correspond to provided signature.

Declaration

public static bool VerifySignature(byte[] data, byte[] signature, byte[] publicKey)

Parameters

Type	Name	Description
System.Byte[]	data	Data that was signed.
System.Byte[]	signature	Signature value to be validated.
System.Byte[]	publicKey	Public key from the key pair that was used to sign the data.

Returns

Type	Description
System.Boolean	True, if signature is valid, False, if signature is invalid.