What is the easiest way to encrypt a password when I save it to the registry

Question

Currently I m writing it in clear text oops   it s an in house program so it s not that bad but I d like to do it right  How should I go about encrypting this when writing to the registry and how do I decrypt it   OurKey SetValue  Password   textBoxPassword Text

User · Answer

You don t decrypt authentication passwords  Hash them using something like the SHA256 provider and when you have to challenge  hash the input from the user and see if the two hashes match  byte   data   System Text Encoding ASCII GetBytes inputString   data   new System Security Cryptography SHA256Managed   ComputeHash data   String hash   System Text Encoding ASCII GetString data    Leaving passwords reversible is a really horrible model  Edit2  I thought we were just talking about front-line authentication  Sure there are cases where you want to encrypt passwords for other things that need to be reversible but there should be a 1-way lock on top of it all  with a very few exceptions   I ve upgraded the hashing algorithm but for the best possible strength you want to keep a private salt and add that to your input before hashing it  You would do this again when you compare  This adds another layer making it even harder for somebody to reverse

User · Answer

One option would be to store the hash  SHA1  MD5  of the password instead of the clear-text password  and whenever you want to see if the password is good  just compare it to that hash   If you need secure storage  for example for a password that you will use to connect to a service   then the problem is more complicated   If it is just for authentication  then it would be enough to use the hash

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This is what you would like to do   OurKey SetValue  Password   StringEncryptor EncryptString textBoxPassword Text    OurKey GetValue  Password   StringEncryptor DecryptString textBoxPassword Text      You can do that with this the following classes  This class is a generic class is the client endpoint  It enables IOC of various encryption algorithms using Ninject   public class StringEncryptor       private static IKernel  kernel       static StringEncryptor                  kernel   new StandardKernel new EncryptionModule                public static string EncryptString string plainText                return  kernel Get lt IStringEncryptor gt    EncryptString plainText              public static string DecryptString string encryptedText                return  kernel Get lt IStringEncryptor gt    DecryptString encryptedText             This next class is the ninject class that allows you to inject the various algorithms   public class EncryptionModule   StandardModule       public override void Load                 Bind lt IStringEncryptor gt    To lt TripleDESStringEncryptor gt               This is the interface that any algorithm needs to implement to encrypt decrypt strings   public interface IStringEncryptor       string EncryptString string plainText       string DecryptString string encryptedText       This is a implementation using the TripleDES algorithm   public class TripleDESStringEncryptor   IStringEncryptor       private byte    key      private byte    iv      private TripleDESCryptoServiceProvider  provider       public TripleDESStringEncryptor                  key   System Text ASCIIEncoding ASCII GetBytes  GSYAHAGCBDUUADIADKOPAAAW             iv   System Text ASCIIEncoding ASCII GetBytes  USAZBGAW             provider   new TripleDESCryptoServiceProvider                region IStringEncryptor Members      public string EncryptString string plainText                return Transform plainText   provider CreateEncryptor  key   iv               public string DecryptString string encryptedText                return Transform encryptedText   provider CreateDecryptor  key   iv                endregion      private string Transform string text  ICryptoTransform transform                if  text    null                        return null                    using  MemoryStream stream   new MemoryStream                          using  CryptoStream cryptoStream   new CryptoStream stream  transform  CryptoStreamMode Write                                 byte   input   Encoding Default GetBytes text                   cryptoStream Write input  0  input Length                   cryptoStream FlushFinalBlock                     return Encoding Default GetString stream ToArray                                       You can watch my video and download the code for this at   http   www wrightin gs 2008 11 how-to-encryptdecrypt-sensitive-column-contents-in-nhibernateactive-record-video html

User · Answer

If you want to be able to decrypt the password  I think the easiest way would be to use DPAPI  user store mode  to encrypt decrypt  This way you don t have to fiddle with encryption keys  store them somewhere or hard-code them in your code - in both cases somebody can discover them by looking into registry  user settings or using Reflector   Otherwise use hashes SHA1 or MD5 like others have said here

User · Answer

If it s a password used for authentication by your application  then hash the password as others suggest   If you re storing passwords for an external resource  you ll often want to be able to prompt the user for these credentials and give him the opportunity to save them securely   Windows provides the Credentials UI  CredUI  for this purpose - there are a number of samples showing how to use this in  NET  including this one on MSDN

User · Answer

Please also consider  salting  your hash  not a culinary concept    Basically  that means appending some random text to the password before you hash it    The salt value helps to slow an attacker perform a dictionary attack should your credential store be compromised  giving you additional time to detect and react to the compromise    To store password hashes   a  Generate a random salt value   byte   salt   new byte 32   System Security Cryptography RNGCryptoServiceProvider Create   GetBytes salt     b  Append the salt to the password      Convert the plain string pwd into bytes byte   plainTextBytes   System Text UnicodeEncoding Unicode GetBytes plainText      Append salt to pwd before hashing byte   combinedBytes   new byte plainTextBytes Length   salt Length   System Buffer BlockCopy plainTextBytes  0  combinedBytes  0  plainTextBytes Length   System Buffer BlockCopy salt  0  combinedBytes  plainTextBytes Length  salt Length     c  Hash the combined password  amp  salt      Create hash for the pwd salt System Security Cryptography HashAlgorithm hashAlgo   new System Security Cryptography SHA256Managed    byte   hash   hashAlgo ComputeHash combinedBytes     d  Append the salt to the resultant hash      Append the salt to the hash byte   hashPlusSalt   new byte hash Length   salt Length   System Buffer BlockCopy hash  0  hashPlusSalt  0  hash Length   System Buffer BlockCopy salt  0  hashPlusSalt  hash Length  salt Length     e  Store the result in your user store database   This approach means you don t need to store the salt separately and then recompute the hash using the salt value and the plaintext password value obtained from the user   Edit  As raw computing power becomes cheaper and faster  the value of hashing -- or salting hashes -- has declined  Jeff Atwood has an excellent 2012 update too lengthy to repeat in its entirety here which states      This  using salted hashes  will provide the illusion of security more than any actual security  Since you need both the salt and the choice of hash algorithm to generate the hash  and to check the hash  it s unlikely an attacker would have one but not the other  If you ve been compromised to the point that an attacker has your password database  it s reasonable to assume they either have or can get your secret  hidden salt       The first rule of security is to always assume and plan for the worst    Should you use a salt  ideally a random salt for each user  Sure  it s   definitely a good practice  and at the very least it lets you   disambiguate two users who have the same password  But these days    salts alone can no longer save you from a person willing to spend a   few thousand dollars on video card hardware  and if you think they   can  you re in trouble

User · Answer

Rather than encrypt decrypt  you should be passing the password through a hashing algorithm  md5 sha512  or similar  What you would ideally do is hash the password and store the hash  then when the password is needed  you hash the entry and compare the entries   A password will then never be  decrypted   simply hashed and then compared

User · Answer

NET provides cryptographics services in class contained in the System Security Cryptography namespace

User · Answer

If you need more than this  for example securing a connection string  for connection to a database   check this article  as it provides the best  option  for this   Oli s answer is also good  as it shows how you can create a hash for a string

User · Answer

You don t decrypt authentication passwords  Hash them using something like the SHA256 provider and when you have to challenge  hash the input from the user and see if the two hashes match  byte   data   System Text Encoding ASCII GetBytes inputString   data   new System Security Cryptography SHA256Managed   ComputeHash data   String hash   System Text Encoding ASCII GetString data    Leaving passwords reversible is a really horrible model  Edit2  I thought we were just talking about front-line authentication  Sure there are cases where you want to encrypt passwords for other things that need to be reversible but there should be a 1-way lock on top of it all  with a very few exceptions   I ve upgraded the hashing algorithm but for the best possible strength you want to keep a private salt and add that to your input before hashing it  You would do this again when you compare  This adds another layer making it even harder for somebody to reverse

User · Answer

You don t decrypt authentication passwords  Hash them using something like the SHA256 provider and when you have to challenge  hash the input from the user and see if the two hashes match  byte   data   System Text Encoding ASCII GetBytes inputString   data   new System Security Cryptography SHA256Managed   ComputeHash data   String hash   System Text Encoding ASCII GetString data    Leaving passwords reversible is a really horrible model  Edit2  I thought we were just talking about front-line authentication  Sure there are cases where you want to encrypt passwords for other things that need to be reversible but there should be a 1-way lock on top of it all  with a very few exceptions   I ve upgraded the hashing algorithm but for the best possible strength you want to keep a private salt and add that to your input before hashing it  You would do this again when you compare  This adds another layer making it even harder for somebody to reverse

User · Answer

One option would be to store the hash  SHA1  MD5  of the password instead of the clear-text password  and whenever you want to see if the password is good  just compare it to that hash   If you need secure storage  for example for a password that you will use to connect to a service   then the problem is more complicated   If it is just for authentication  then it would be enough to use the hash

User · Answer

NET provides cryptographics services in class contained in the System Security Cryptography namespace

User · Answer

Rather than encrypt decrypt  you should be passing the password through a hashing algorithm  md5 sha512  or similar  What you would ideally do is hash the password and store the hash  then when the password is needed  you hash the entry and compare the entries   A password will then never be  decrypted   simply hashed and then compared

User · Answer

Like ligget78 said  DPAPI would be a good way to go for storing passwords  Check out the ProtectedData class on MSDN for example usage

User · Answer

One option would be to store the hash  SHA1  MD5  of the password instead of the clear-text password  and whenever you want to see if the password is good  just compare it to that hash   If you need secure storage  for example for a password that you will use to connect to a service   then the problem is more complicated   If it is just for authentication  then it would be enough to use the hash

User · Answer

NET provides cryptographics services in class contained in the System Security Cryptography namespace

User · Answer

You don t decrypt authentication passwords  Hash them using something like the SHA256 provider and when you have to challenge  hash the input from the user and see if the two hashes match  byte   data   System Text Encoding ASCII GetBytes inputString   data   new System Security Cryptography SHA256Managed   ComputeHash data   String hash   System Text Encoding ASCII GetString data    Leaving passwords reversible is a really horrible model  Edit2  I thought we were just talking about front-line authentication  Sure there are cases where you want to encrypt passwords for other things that need to be reversible but there should be a 1-way lock on top of it all  with a very few exceptions   I ve upgraded the hashing algorithm but for the best possible strength you want to keep a private salt and add that to your input before hashing it  You would do this again when you compare  This adds another layer making it even harder for somebody to reverse

User · Answer

Rather than encrypt decrypt  you should be passing the password through a hashing algorithm  md5 sha512  or similar  What you would ideally do is hash the password and store the hash  then when the password is needed  you hash the entry and compare the entries   A password will then never be  decrypted   simply hashed and then compared

User · Answer

I have looked all over for a good example of encryption and decryption process but most were overly complex    Anyhow there are many reasons someone may want to decrypt some text values including passwords  The reason I need to decrypt the password on the site I am working on currently is because they want to make sure when someone is forced to change their password when it expires that we do not let them change it with a close variant of the same password they used in the last x months    So I wrote up a process that will do this in a simplified manner  I hope this code is beneficial to someone  For all I know I may end up using this at another time for a different company site   public string GenerateAPassKey string passphrase                   Pass Phrase can be any string         string passPhrase   passphrase             Salt Value can be any string for simplicity use the same value as used for the pass phrase          string saltValue   passphrase             Hash Algorithm can be  SHA1 or MD5          string hashAlgorithm    SHA1              Password Iterations can be any number         int passwordIterations   2             Key Size can be 128 192 or 256         int keySize   256             Convert Salt passphrase string to a Byte Array         byte   saltValueBytes   Encoding ASCII GetBytes saltValue              Using System Security Cryptography PasswordDeriveBytes to create the Key         PasswordDeriveBytes pdb   new PasswordDeriveBytes passPhrase  saltValueBytes  hashAlgorithm  passwordIterations             When creating a Key Byte array from the base64 string the Key must have 32 dimensions          byte   Key   pdb GetBytes keySize   11           String KeyString   Convert ToBase64String Key            return KeyString            Save the keystring some place like your database and use it to decrypt and encrypt   any text string or text file etc  Make sure you dont lose it though    private static string Encrypt string plainStr  string KeyString                                    RijndaelManaged aesEncryption   new RijndaelManaged            aesEncryption KeySize   256          aesEncryption BlockSize   128          aesEncryption Mode   CipherMode ECB          aesEncryption Padding   PaddingMode ISO10126          byte   KeyInBytes   Encoding UTF8 GetBytes KeyString           aesEncryption Key   KeyInBytes          byte   plainText   ASCIIEncoding UTF8 GetBytes plainStr           ICryptoTransform crypto   aesEncryption CreateEncryptor            byte   cipherText   crypto TransformFinalBlock plainText  0  plainText Length           return Convert ToBase64String cipherText           private static string Decrypt string encryptedText  string KeyString                 RijndaelManaged aesEncryption   new RijndaelManaged             aesEncryption KeySize   256          aesEncryption BlockSize   128           aesEncryption Mode   CipherMode ECB          aesEncryption Padding   PaddingMode ISO10126          byte   KeyInBytes   Encoding UTF8 GetBytes KeyString           aesEncryption Key   KeyInBytes          ICryptoTransform decrypto   aesEncryption CreateDecryptor             byte   encryptedBytes   Convert FromBase64CharArray encryptedText ToCharArray    0  encryptedText Length            return ASCIIEncoding UTF8 GetString decrypto TransformFinalBlock encryptedBytes  0  encryptedBytes Length             String KeyString   GenerateAPassKey  PassKey     String EncryptedPassword   Encrypt  25Characterlengthpassword    KeyString    String DecryptedPassword   Decrypt EncryptedPassword  KeyString

User · Answer

If you need more than this  for example securing a connection string  for connection to a database   check this article  as it provides the best  option  for this   Oli s answer is also good  as it shows how you can create a hash for a string

User · Answer

If it s a password used for authentication by your application  then hash the password as others suggest   If you re storing passwords for an external resource  you ll often want to be able to prompt the user for these credentials and give him the opportunity to save them securely   Windows provides the Credentials UI  CredUI  for this purpose - there are a number of samples showing how to use this in  NET  including this one on MSDN

User · Answer

If you need more than this  for example securing a connection string  for connection to a database   check this article  as it provides the best  option  for this   Oli s answer is also good  as it shows how you can create a hash for a string

User · Answer

If it s a password used for authentication by your application  then hash the password as others suggest   If you re storing passwords for an external resource  you ll often want to be able to prompt the user for these credentials and give him the opportunity to save them securely   Windows provides the Credentials UI  CredUI  for this purpose - there are a number of samples showing how to use this in  NET  including this one on MSDN

User · Answer

This is what you would like to do   OurKey SetValue  Password   StringEncryptor EncryptString textBoxPassword Text    OurKey GetValue  Password   StringEncryptor DecryptString textBoxPassword Text      You can do that with this the following classes  This class is a generic class is the client endpoint  It enables IOC of various encryption algorithms using Ninject   public class StringEncryptor       private static IKernel  kernel       static StringEncryptor                  kernel   new StandardKernel new EncryptionModule                public static string EncryptString string plainText                return  kernel Get lt IStringEncryptor gt    EncryptString plainText              public static string DecryptString string encryptedText                return  kernel Get lt IStringEncryptor gt    DecryptString encryptedText             This next class is the ninject class that allows you to inject the various algorithms   public class EncryptionModule   StandardModule       public override void Load                 Bind lt IStringEncryptor gt    To lt TripleDESStringEncryptor gt               This is the interface that any algorithm needs to implement to encrypt decrypt strings   public interface IStringEncryptor       string EncryptString string plainText       string DecryptString string encryptedText       This is a implementation using the TripleDES algorithm   public class TripleDESStringEncryptor   IStringEncryptor       private byte    key      private byte    iv      private TripleDESCryptoServiceProvider  provider       public TripleDESStringEncryptor                  key   System Text ASCIIEncoding ASCII GetBytes  GSYAHAGCBDUUADIADKOPAAAW             iv   System Text ASCIIEncoding ASCII GetBytes  USAZBGAW             provider   new TripleDESCryptoServiceProvider                region IStringEncryptor Members      public string EncryptString string plainText                return Transform plainText   provider CreateEncryptor  key   iv               public string DecryptString string encryptedText                return Transform encryptedText   provider CreateDecryptor  key   iv                endregion      private string Transform string text  ICryptoTransform transform                if  text    null                        return null                    using  MemoryStream stream   new MemoryStream                          using  CryptoStream cryptoStream   new CryptoStream stream  transform  CryptoStreamMode Write                                 byte   input   Encoding Default GetBytes text                   cryptoStream Write input  0  input Length                   cryptoStream FlushFinalBlock                     return Encoding Default GetString stream ToArray                                       You can watch my video and download the code for this at   http   www wrightin gs 2008 11 how-to-encryptdecrypt-sensitive-column-contents-in-nhibernateactive-record-video html

User · Answer

If it s a password used for authentication by your application  then hash the password as others suggest   If you re storing passwords for an external resource  you ll often want to be able to prompt the user for these credentials and give him the opportunity to save them securely   Windows provides the Credentials UI  CredUI  for this purpose - there are a number of samples showing how to use this in  NET  including this one on MSDN

User · Answer

Please also consider  salting  your hash  not a culinary concept    Basically  that means appending some random text to the password before you hash it    The salt value helps to slow an attacker perform a dictionary attack should your credential store be compromised  giving you additional time to detect and react to the compromise    To store password hashes   a  Generate a random salt value   byte   salt   new byte 32   System Security Cryptography RNGCryptoServiceProvider Create   GetBytes salt     b  Append the salt to the password      Convert the plain string pwd into bytes byte   plainTextBytes   System Text UnicodeEncoding Unicode GetBytes plainText      Append salt to pwd before hashing byte   combinedBytes   new byte plainTextBytes Length   salt Length   System Buffer BlockCopy plainTextBytes  0  combinedBytes  0  plainTextBytes Length   System Buffer BlockCopy salt  0  combinedBytes  plainTextBytes Length  salt Length     c  Hash the combined password  amp  salt      Create hash for the pwd salt System Security Cryptography HashAlgorithm hashAlgo   new System Security Cryptography SHA256Managed    byte   hash   hashAlgo ComputeHash combinedBytes     d  Append the salt to the resultant hash      Append the salt to the hash byte   hashPlusSalt   new byte hash Length   salt Length   System Buffer BlockCopy hash  0  hashPlusSalt  0  hash Length   System Buffer BlockCopy salt  0  hashPlusSalt  hash Length  salt Length     e  Store the result in your user store database   This approach means you don t need to store the salt separately and then recompute the hash using the salt value and the plaintext password value obtained from the user   Edit  As raw computing power becomes cheaper and faster  the value of hashing -- or salting hashes -- has declined  Jeff Atwood has an excellent 2012 update too lengthy to repeat in its entirety here which states      This  using salted hashes  will provide the illusion of security more than any actual security  Since you need both the salt and the choice of hash algorithm to generate the hash  and to check the hash  it s unlikely an attacker would have one but not the other  If you ve been compromised to the point that an attacker has your password database  it s reasonable to assume they either have or can get your secret  hidden salt       The first rule of security is to always assume and plan for the worst    Should you use a salt  ideally a random salt for each user  Sure  it s   definitely a good practice  and at the very least it lets you   disambiguate two users who have the same password  But these days    salts alone can no longer save you from a person willing to spend a   few thousand dollars on video card hardware  and if you think they   can  you re in trouble

User · Answer

If you want to be able to decrypt the password  I think the easiest way would be to use DPAPI  user store mode  to encrypt decrypt  This way you don t have to fiddle with encryption keys  store them somewhere or hard-code them in your code - in both cases somebody can discover them by looking into registry  user settings or using Reflector   Otherwise use hashes SHA1 or MD5 like others have said here

User · Answer

This is what you would like to do   OurKey SetValue  Password   StringEncryptor EncryptString textBoxPassword Text    OurKey GetValue  Password   StringEncryptor DecryptString textBoxPassword Text      You can do that with this the following classes  This class is a generic class is the client endpoint  It enables IOC of various encryption algorithms using Ninject   public class StringEncryptor       private static IKernel  kernel       static StringEncryptor                  kernel   new StandardKernel new EncryptionModule                public static string EncryptString string plainText                return  kernel Get lt IStringEncryptor gt    EncryptString plainText              public static string DecryptString string encryptedText                return  kernel Get lt IStringEncryptor gt    DecryptString encryptedText             This next class is the ninject class that allows you to inject the various algorithms   public class EncryptionModule   StandardModule       public override void Load                 Bind lt IStringEncryptor gt    To lt TripleDESStringEncryptor gt               This is the interface that any algorithm needs to implement to encrypt decrypt strings   public interface IStringEncryptor       string EncryptString string plainText       string DecryptString string encryptedText       This is a implementation using the TripleDES algorithm   public class TripleDESStringEncryptor   IStringEncryptor       private byte    key      private byte    iv      private TripleDESCryptoServiceProvider  provider       public TripleDESStringEncryptor                  key   System Text ASCIIEncoding ASCII GetBytes  GSYAHAGCBDUUADIADKOPAAAW             iv   System Text ASCIIEncoding ASCII GetBytes  USAZBGAW             provider   new TripleDESCryptoServiceProvider                region IStringEncryptor Members      public string EncryptString string plainText                return Transform plainText   provider CreateEncryptor  key   iv               public string DecryptString string encryptedText                return Transform encryptedText   provider CreateDecryptor  key   iv                endregion      private string Transform string text  ICryptoTransform transform                if  text    null                        return null                    using  MemoryStream stream   new MemoryStream                          using  CryptoStream cryptoStream   new CryptoStream stream  transform  CryptoStreamMode Write                                 byte   input   Encoding Default GetBytes text                   cryptoStream Write input  0  input Length                   cryptoStream FlushFinalBlock                     return Encoding Default GetString stream ToArray                                       You can watch my video and download the code for this at   http   www wrightin gs 2008 11 how-to-encryptdecrypt-sensitive-column-contents-in-nhibernateactive-record-video html

User · Answer

One option would be to store the hash  SHA1  MD5  of the password instead of the clear-text password  and whenever you want to see if the password is good  just compare it to that hash   If you need secure storage  for example for a password that you will use to connect to a service   then the problem is more complicated   If it is just for authentication  then it would be enough to use the hash

User · Answer

NET provides cryptographics services in class contained in the System Security Cryptography namespace

User · Answer

Please also consider  salting  your hash  not a culinary concept    Basically  that means appending some random text to the password before you hash it    The salt value helps to slow an attacker perform a dictionary attack should your credential store be compromised  giving you additional time to detect and react to the compromise    To store password hashes   a  Generate a random salt value   byte   salt   new byte 32   System Security Cryptography RNGCryptoServiceProvider Create   GetBytes salt     b  Append the salt to the password      Convert the plain string pwd into bytes byte   plainTextBytes   System Text UnicodeEncoding Unicode GetBytes plainText      Append salt to pwd before hashing byte   combinedBytes   new byte plainTextBytes Length   salt Length   System Buffer BlockCopy plainTextBytes  0  combinedBytes  0  plainTextBytes Length   System Buffer BlockCopy salt  0  combinedBytes  plainTextBytes Length  salt Length     c  Hash the combined password  amp  salt      Create hash for the pwd salt System Security Cryptography HashAlgorithm hashAlgo   new System Security Cryptography SHA256Managed    byte   hash   hashAlgo ComputeHash combinedBytes     d  Append the salt to the resultant hash      Append the salt to the hash byte   hashPlusSalt   new byte hash Length   salt Length   System Buffer BlockCopy hash  0  hashPlusSalt  0  hash Length   System Buffer BlockCopy salt  0  hashPlusSalt  hash Length  salt Length     e  Store the result in your user store database   This approach means you don t need to store the salt separately and then recompute the hash using the salt value and the plaintext password value obtained from the user   Edit  As raw computing power becomes cheaper and faster  the value of hashing -- or salting hashes -- has declined  Jeff Atwood has an excellent 2012 update too lengthy to repeat in its entirety here which states      This  using salted hashes  will provide the illusion of security more than any actual security  Since you need both the salt and the choice of hash algorithm to generate the hash  and to check the hash  it s unlikely an attacker would have one but not the other  If you ve been compromised to the point that an attacker has your password database  it s reasonable to assume they either have or can get your secret  hidden salt       The first rule of security is to always assume and plan for the worst    Should you use a salt  ideally a random salt for each user  Sure  it s   definitely a good practice  and at the very least it lets you   disambiguate two users who have the same password  But these days    salts alone can no longer save you from a person willing to spend a   few thousand dollars on video card hardware  and if you think they   can  you re in trouble

User · Answer

If you want to be able to decrypt the password  I think the easiest way would be to use DPAPI  user store mode  to encrypt decrypt  This way you don t have to fiddle with encryption keys  store them somewhere or hard-code them in your code - in both cases somebody can discover them by looking into registry  user settings or using Reflector   Otherwise use hashes SHA1 or MD5 like others have said here

User · Answer

Please also consider  salting  your hash  not a culinary concept    Basically  that means appending some random text to the password before you hash it    The salt value helps to slow an attacker perform a dictionary attack should your credential store be compromised  giving you additional time to detect and react to the compromise    To store password hashes   a  Generate a random salt value   byte   salt   new byte 32   System Security Cryptography RNGCryptoServiceProvider Create   GetBytes salt     b  Append the salt to the password      Convert the plain string pwd into bytes byte   plainTextBytes   System Text UnicodeEncoding Unicode GetBytes plainText      Append salt to pwd before hashing byte   combinedBytes   new byte plainTextBytes Length   salt Length   System Buffer BlockCopy plainTextBytes  0  combinedBytes  0  plainTextBytes Length   System Buffer BlockCopy salt  0  combinedBytes  plainTextBytes Length  salt Length     c  Hash the combined password  amp  salt      Create hash for the pwd salt System Security Cryptography HashAlgorithm hashAlgo   new System Security Cryptography SHA256Managed    byte   hash   hashAlgo ComputeHash combinedBytes     d  Append the salt to the resultant hash      Append the salt to the hash byte   hashPlusSalt   new byte hash Length   salt Length   System Buffer BlockCopy hash  0  hashPlusSalt  0  hash Length   System Buffer BlockCopy salt  0  hashPlusSalt  hash Length  salt Length     e  Store the result in your user store database   This approach means you don t need to store the salt separately and then recompute the hash using the salt value and the plaintext password value obtained from the user   Edit  As raw computing power becomes cheaper and faster  the value of hashing -- or salting hashes -- has declined  Jeff Atwood has an excellent 2012 update too lengthy to repeat in its entirety here which states      This  using salted hashes  will provide the illusion of security more than any actual security  Since you need both the salt and the choice of hash algorithm to generate the hash  and to check the hash  it s unlikely an attacker would have one but not the other  If you ve been compromised to the point that an attacker has your password database  it s reasonable to assume they either have or can get your secret  hidden salt       The first rule of security is to always assume and plan for the worst    Should you use a salt  ideally a random salt for each user  Sure  it s   definitely a good practice  and at the very least it lets you   disambiguate two users who have the same password  But these days    salts alone can no longer save you from a person willing to spend a   few thousand dollars on video card hardware  and if you think they   can  you re in trouble

User · Answer

If you need more than this  for example securing a connection string  for connection to a database   check this article  as it provides the best  option  for this   Oli s answer is also good  as it shows how you can create a hash for a string

User · Answer

Tom Scott got it right in his coverage of how  not  to store passwords  on Computerphile   https   www youtube com watch v 8ZtInClXe1Q   If you can at all avoid it  do not try to store passwords yourself  Use a separate  pre-established  trustworthy user authentication platform  e g   OAuth providers  you company s Active Directory domain  etc   instead  If you must store passwords  don t follow any of the guidance here  At least  not without also consulting more recent and reputable publications applicable to your language of choice    There s certainly a lot of smart people here  and probably even some good guidance given  But the odds are strong that  by the time you read this  all of the answers here  including this one  will already be outdated     The right way to store passwords changes over time   Probably more frequently than some people change their underwear     All that said  here s some general guidance that will hopefully remain useful for awhile    Don t encrypt passwords  Any storage method that allows recovery of the stored data is inherently insecure for the purpose of holding passwords - all forms of encryption included  Process the passwords exactly as entered by the user during the creation process  Anything you do to the password before sending it to the cryptography module will probably just weaken it  Doing any of the following also just adds complexity to the password storage  amp  verification process  which could cause other problems  perhaps even introduce vulnerabilities  down the road    Don t convert to all-uppercase all-lowercase  Don t remove whitespace  Don t strip unacceptable characters or strings  Don t change the text encoding  Don t do any character or string substitutions  Don t truncate passwords of any length   Reject creation of any passwords that can t be stored without modification  Reinforcing the above  If there s some reason your password storage mechanism can t appropriately handle certain characters  whitespaces  strings  or password lengths  then return an error and let the user know about the system s limitations so they can retry with a password that fits within them  For a better user experience  make a list of those limitations accessible to the user up-front  Don t even worry about  let alone bother  hiding the list from attackers - they ll figure it out easily enough on their own anyway  Use a long  random  and unique salt for each account  No two accounts  passwords should ever look the same in storage  even if the passwords are actually identical  Use slow and cryptographically strong hashing algorithms that are designed for use with passwords  MD5 is certainly out  SHA-1 SHA-2 are no-go  But I m not going to tell you what you should use here either   See the first  2 bullet in this post   Iterate as much as you can tolerate  While your system might have better things to do with its processor cycles than hash passwords all day  the people who will be cracking your passwords have systems that don t  Make it as hard on them as you can  without quite making it  too hard  on you      Most importantly     Don t just listen to anyone here   Go look up a reputable and very recent publication on the proper methods of password storage for your language of choice  Actually  you should find multiple recent publications from multiple separate sources that are in agreement before you settle on one method   It s extremely possible that everything that everyone here  myself included  has said has already been superseded by better technologies or rendered insecure by newly developed attack methods  Go find something that s more probably not

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This is what you would like to do   OurKey SetValue  Password   StringEncryptor EncryptString textBoxPassword Text    OurKey GetValue  Password   StringEncryptor DecryptString textBoxPassword Text      You can do that with this the following classes  This class is a generic class is the client endpoint  It enables IOC of various encryption algorithms using Ninject   public class StringEncryptor       private static IKernel  kernel       static StringEncryptor                  kernel   new StandardKernel new EncryptionModule                public static string EncryptString string plainText                return  kernel Get lt IStringEncryptor gt    EncryptString plainText              public static string DecryptString string encryptedText                return  kernel Get lt IStringEncryptor gt    DecryptString encryptedText             This next class is the ninject class that allows you to inject the various algorithms   public class EncryptionModule   StandardModule       public override void Load                 Bind lt IStringEncryptor gt    To lt TripleDESStringEncryptor gt               This is the interface that any algorithm needs to implement to encrypt decrypt strings   public interface IStringEncryptor       string EncryptString string plainText       string DecryptString string encryptedText       This is a implementation using the TripleDES algorithm   public class TripleDESStringEncryptor   IStringEncryptor       private byte    key      private byte    iv      private TripleDESCryptoServiceProvider  provider       public TripleDESStringEncryptor                  key   System Text ASCIIEncoding ASCII GetBytes  GSYAHAGCBDUUADIADKOPAAAW             iv   System Text ASCIIEncoding ASCII GetBytes  USAZBGAW             provider   new TripleDESCryptoServiceProvider                region IStringEncryptor Members      public string EncryptString string plainText                return Transform plainText   provider CreateEncryptor  key   iv               public string DecryptString string encryptedText                return Transform encryptedText   provider CreateDecryptor  key   iv                endregion      private string Transform string text  ICryptoTransform transform                if  text    null                        return null                    using  MemoryStream stream   new MemoryStream                          using  CryptoStream cryptoStream   new CryptoStream stream  transform  CryptoStreamMode Write                                 byte   input   Encoding Default GetBytes text                   cryptoStream Write input  0  input Length                   cryptoStream FlushFinalBlock                     return Encoding Default GetString stream ToArray                                       You can watch my video and download the code for this at   http   www wrightin gs 2008 11 how-to-encryptdecrypt-sensitive-column-contents-in-nhibernateactive-record-video html

User · Answer

If you want to be able to decrypt the password  I think the easiest way would be to use DPAPI  user store mode  to encrypt decrypt  This way you don t have to fiddle with encryption keys  store them somewhere or hard-code them in your code - in both cases somebody can discover them by looking into registry  user settings or using Reflector   Otherwise use hashes SHA1 or MD5 like others have said here

User · Answer

Rather than encrypt decrypt  you should be passing the password through a hashing algorithm  md5 sha512  or similar  What you would ideally do is hash the password and store the hash  then when the password is needed  you hash the entry and compare the entries   A password will then never be  decrypted   simply hashed and then compared

User · Answer

Like ligget78 said  DPAPI would be a good way to go for storing passwords  Check out the ProtectedData class on MSDN for example usage

User · Answer

Tom Scott got it right in his coverage of how  not  to store passwords  on Computerphile   https   www youtube com watch v 8ZtInClXe1Q   If you can at all avoid it  do not try to store passwords yourself  Use a separate  pre-established  trustworthy user authentication platform  e g   OAuth providers  you company s Active Directory domain  etc   instead  If you must store passwords  don t follow any of the guidance here  At least  not without also consulting more recent and reputable publications applicable to your language of choice    There s certainly a lot of smart people here  and probably even some good guidance given  But the odds are strong that  by the time you read this  all of the answers here  including this one  will already be outdated     The right way to store passwords changes over time   Probably more frequently than some people change their underwear     All that said  here s some general guidance that will hopefully remain useful for awhile    Don t encrypt passwords  Any storage method that allows recovery of the stored data is inherently insecure for the purpose of holding passwords - all forms of encryption included  Process the passwords exactly as entered by the user during the creation process  Anything you do to the password before sending it to the cryptography module will probably just weaken it  Doing any of the following also just adds complexity to the password storage  amp  verification process  which could cause other problems  perhaps even introduce vulnerabilities  down the road    Don t convert to all-uppercase all-lowercase  Don t remove whitespace  Don t strip unacceptable characters or strings  Don t change the text encoding  Don t do any character or string substitutions  Don t truncate passwords of any length   Reject creation of any passwords that can t be stored without modification  Reinforcing the above  If there s some reason your password storage mechanism can t appropriately handle certain characters  whitespaces  strings  or password lengths  then return an error and let the user know about the system s limitations so they can retry with a password that fits within them  For a better user experience  make a list of those limitations accessible to the user up-front  Don t even worry about  let alone bother  hiding the list from attackers - they ll figure it out easily enough on their own anyway  Use a long  random  and unique salt for each account  No two accounts  passwords should ever look the same in storage  even if the passwords are actually identical  Use slow and cryptographically strong hashing algorithms that are designed for use with passwords  MD5 is certainly out  SHA-1 SHA-2 are no-go  But I m not going to tell you what you should use here either   See the first  2 bullet in this post   Iterate as much as you can tolerate  While your system might have better things to do with its processor cycles than hash passwords all day  the people who will be cracking your passwords have systems that don t  Make it as hard on them as you can  without quite making it  too hard  on you      Most importantly     Don t just listen to anyone here   Go look up a reputable and very recent publication on the proper methods of password storage for your language of choice  Actually  you should find multiple recent publications from multiple separate sources that are in agreement before you settle on one method   It s extremely possible that everything that everyone here  myself included  has said has already been superseded by better technologies or rendered insecure by newly developed attack methods  Go find something that s more probably not

User · Answer

I have looked all over for a good example of encryption and decryption process but most were overly complex    Anyhow there are many reasons someone may want to decrypt some text values including passwords  The reason I need to decrypt the password on the site I am working on currently is because they want to make sure when someone is forced to change their password when it expires that we do not let them change it with a close variant of the same password they used in the last x months    So I wrote up a process that will do this in a simplified manner  I hope this code is beneficial to someone  For all I know I may end up using this at another time for a different company site   public string GenerateAPassKey string passphrase                   Pass Phrase can be any string         string passPhrase   passphrase             Salt Value can be any string for simplicity use the same value as used for the pass phrase          string saltValue   passphrase             Hash Algorithm can be  SHA1 or MD5          string hashAlgorithm    SHA1              Password Iterations can be any number         int passwordIterations   2             Key Size can be 128 192 or 256         int keySize   256             Convert Salt passphrase string to a Byte Array         byte   saltValueBytes   Encoding ASCII GetBytes saltValue              Using System Security Cryptography PasswordDeriveBytes to create the Key         PasswordDeriveBytes pdb   new PasswordDeriveBytes passPhrase  saltValueBytes  hashAlgorithm  passwordIterations             When creating a Key Byte array from the base64 string the Key must have 32 dimensions          byte   Key   pdb GetBytes keySize   11           String KeyString   Convert ToBase64String Key            return KeyString            Save the keystring some place like your database and use it to decrypt and encrypt   any text string or text file etc  Make sure you dont lose it though    private static string Encrypt string plainStr  string KeyString                                    RijndaelManaged aesEncryption   new RijndaelManaged            aesEncryption KeySize   256          aesEncryption BlockSize   128          aesEncryption Mode   CipherMode ECB          aesEncryption Padding   PaddingMode ISO10126          byte   KeyInBytes   Encoding UTF8 GetBytes KeyString           aesEncryption Key   KeyInBytes          byte   plainText   ASCIIEncoding UTF8 GetBytes plainStr           ICryptoTransform crypto   aesEncryption CreateEncryptor            byte   cipherText   crypto TransformFinalBlock plainText  0  plainText Length           return Convert ToBase64String cipherText           private static string Decrypt string encryptedText  string KeyString                 RijndaelManaged aesEncryption   new RijndaelManaged             aesEncryption KeySize   256          aesEncryption BlockSize   128           aesEncryption Mode   CipherMode ECB          aesEncryption Padding   PaddingMode ISO10126          byte   KeyInBytes   Encoding UTF8 GetBytes KeyString           aesEncryption Key   KeyInBytes          ICryptoTransform decrypto   aesEncryption CreateDecryptor             byte   encryptedBytes   Convert FromBase64CharArray encryptedText ToCharArray    0  encryptedText Length            return ASCIIEncoding UTF8 GetString decrypto TransformFinalBlock encryptedBytes  0  encryptedBytes Length             String KeyString   GenerateAPassKey  PassKey     String EncryptedPassword   Encrypt  25Characterlengthpassword    KeyString    String DecryptedPassword   Decrypt EncryptedPassword  KeyString

[c#] What is the easiest way to encrypt a password when I save it to the registry?

You don't decrypt authentication passwords!

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