Encrypt and Decrypt text with RSA in PHP

Question

Is there any class for PHP 5 3 that provides RSA encryption decryption without padding   I ve got private and public key  p q  and modulus

User · Accepted Answer

You can use phpseclib  a pure PHP RSA implementation    lt  php include  Crypt RSA php      privatekey   file get contents  private key      rsa   new Crypt RSA     rsa- gt loadKey  privatekey     plaintext   new Math BigInteger  aaaaaa    echo  rsa- gt  exponentiate  plaintext - gt toBytes      gt

User · Answer

I have difficulty in decrypting a long string that is encrypted in python  Here is the python encryption function   def RSA encrypt public key  msg  chunk size 214               Encrypt the message by the provided RSA public key        param public key  RSA public key in PEM format       type public key  binary      param msg  message that to be encrypted      type msg  string      param chunk size  the chunk size used for PKCS1 OAEP decryption  it is determined by       the private key length used in bytes - 42 bytes       type chunk size  int      return  Base 64 encryption of the encrypted message      rtype  binray             rsa key   RSA importKey public key      rsa key   PKCS1 OAEP new rsa key       encrypted   b       offset   0     end loop   False      while not end loop          chunk   msg offset offset   chunk size           if len chunk    chunk size    0              chunk           chunk size - len chunk               end loop   True          encrypted    rsa key encrypt chunk encode            offset    chunk size      return base64 b64encode encrypted    The decryption in PHP           param  base64 encoded string holds the encrypted message      param  Resource your private key loaded using openssl pkey get private     param  integer Chunking by bytes to feed to the decryptor algorithm      return String decrypted message      public function RSADecyrpt  encrypted msg   ppk   chunk size 256       if is null  ppk           throw new Exception  Returned message is encrypted while you did not provide private key          encrypted msg   base64 decode  encrypted msg         offset   0       chunk size   256        decrypted           while  offset  lt  strlen  encrypted msg             decrypted chunk                chunk   substr  encrypted msg   offset   chunk size            if openssl private decrypt  chunk   decrypted chunk   ppk  OPENSSL PKCS1 OAEP PADDING                decrypted     decrypted chunk          else              throw new exception  Problem decrypting the message             offset     chunk size            return  decrypted

User · Answer

Yes   Look at http   jerrywickey com test testJerrysLibrary php  It gives sample code examples for RSA encryption and decryption in PHP as well as RSA encryption in javascript   If you want to encrypt text instead of just base 10 numbers   you ll also need a base to base conversion   That is convert text to a very large number   Text is really just writing in base 63   26 lowercase letters plus 26 uppercase   10 numerals   space character   The code for that is below also   The  GETn parameter is a file name that holds keys for the cryption functions   If you don t figure it out  ask   I ll help   I actually posted this whole encryption library yesterday  but Brad Larson a mod  killed it and said this kind of stuff isn t really what Stack Overflow is about  But you can still find all the code examples and the whole function library to carry out client server encryption decryption for AJAX at the link above   function RSAencrypt   num   GETn       if   file exists   temp bigprimes  hash   sha256    GETn    php              t  explode    gt     file get contents  temp bigprimes  hash   sha256    GETn    php             return JL powmod   num   t 4    t 10          else          return false           function RSAdecrypt   num   GETn       if   file exists   temp bigprimes  hash   sha256    GETn    php              t  explode    gt     file get contents  temp bigprimes  hash   sha256    GETn    php             return JL powmod   num   t 8    t 10              else          return false           function JL powmod   num   pow   mod        if   function exists  bcpowmod              return bcpowmod   num   pow   mod              result   1       do           if    bccomp  bcmod   pow   2     1                   result   bcmod  bcmul   result   num    mod                     num   bcmod  bcpow   num   2     mod            pow   bcdiv   pow   2          while   bccomp   pow   0         return  result     function baseToBase   message   fromBase   toBase        from  strlen   fromBase        b  from    fromBase        to  strlen   toBase        b  to    toBase         result  substr   b  to   0  1         f  substr   b  to   1  1         tf  digit   from   b  to         for   i strlen  message -1   i gt  0   i--            result  badd   result  bmul  digit  strpos   b  from   substr   message   i  1     b  to     f   b  to     b  to             f  bmul  f   tf   b  to              return  result      function digit   from   bto           to  strlen   bto        b  to    bto         t 0   intval   from        i  0      while    t  i   gt   intval   to            if    isset   t  i 1                   t  i 1   0                    while    t  i   gt   intval   to                 t  i    t  i  - intval   to                t  i 1                        i                res          for    i count   t -1   i gt  0   i--             res   substr   b  to    t  i   1             return  res        function badd   n1   n2   nbase        base  strlen   nbase        b  base    nbase        while   strlen   n1   lt  strlen   n2             n1  substr   b  base   0  1     n1            while   strlen   n1   gt  strlen   n2             n2  substr   b  base   0  1     n2             n1  substr   b  base   0  1     n1           n2  substr   b  base   0  1     n2       m1  array        for    i 0   i lt strlen   n1    i              m1  i   strpos   b  base   substr   n1   strlen   n1 - i-1   1                  res  array         m2  array        for   i 0   i lt strlen   n1    i              m2  i   strpos   b  base   substr   n2   strlen   n1 - i-1   1             res  i   0                       for   i 0   i lt strlen   n1      i              res  i    m1  i     m2  i     res  i           if   res  i   gt    base                res  i    res  i  -  base               res  i 1                          o          for   i 0   i lt strlen   n1    i              o  substr   b  base    res  i   1   o                t  false       o          for   i strlen   n1 -1   i gt  0   i--           if   res  i   gt  0     t                    o   substr   b  base    res  i   1                t  true                      return  o    function bmul   n1   n2   nbase        base  strlen   nbase        b  base    nbase         m1  array        for   i 0   i lt strlen   n1    i              m1  i   strpos   b  base   substr  n1   strlen   n1 - i-1   1                  m2  array        for   i 0   i lt strlen   n2    i              m2  i   strpos   b  base   substr  n2   strlen   n2 - i-1   1                          res  array        for   i 0   i lt strlen   n1  strlen   n2  2   i              res  i   0            for   i 0   i lt strlen   n1      i             for   j 0   j lt strlen   n2      j                  res  i  j     m1  i     m2  j      res  i  j               while    res  i  j   gt    base                    res  i  j    res  i  j  -  base                   res  i  j 1                                        t  false       o          for   i count   res -1   i gt  0   i--           if   res  i  gt 0     t                  o   substr   b  base    res  i   1                t  true                      return  o

User · Answer

If you are using PHP    7 2 consider using inbuilt sodium core extension for encrption   It is modern and more secure  You can find more information here - http   php net manual en intro sodium php  and here - https   paragonie com book pecl-libsodium read 00-intro md  Example PHP 7 2 sodium encryption class -    lt  php         Simple sodium crypto class for PHP  gt   7 2     author MRK     class crypto                            return type             static public function create encryption key             return base64 encode sodium crypto secretbox keygen                           Encrypt a message                 param string  message - message to encrypt         param string  key - encryption key created using create encryption key           return string             static function encrypt  message   key             key decoded   base64 decode  key            nonce   random bytes                  SODIUM CRYPTO SECRETBOX NONCEBYTES                      cipher   base64 encode                   nonce                   sodium crypto secretbox                           message   nonce   key decoded                                      sodium memzero  message           sodium memzero  key decoded           return  cipher                        Decrypt a message         param string  encrypted - message encrypted with safeEncrypt           param string  key - key used for encryption         return string             static function decrypt  encrypted   key             decoded   base64 decode  encrypted            key decoded   base64 decode  key           if   decoded     false                throw new Exception  Decryption error   the encoding failed                      if  mb strlen  decoded   8bit    lt   SODIUM CRYPTO SECRETBOX NONCEBYTES   SODIUM CRYPTO SECRETBOX MACBYTES                 throw new Exception  Decryption error   the message was truncated                       nonce   mb substr  decoded  0  SODIUM CRYPTO SECRETBOX NONCEBYTES   8bit             ciphertext   mb substr  decoded  SODIUM CRYPTO SECRETBOX NONCEBYTES  null   8bit              plain   sodium crypto secretbox open                   ciphertext   nonce   key decoded                    if   plain     false                throw new Exception  Decryption error   the message was tampered with in transit                      sodium memzero  ciphertext           sodium memzero  key decoded           return  plain             Sample Usage -    lt  php    key   crypto  create encryption key      string    Sri Lanka is a beautiful country      echo  enc   crypto  encrypt  string   key    echo crypto  decrypt  enc   key

User · Answer

Security warning  This code snippet is vulnerable to Bleichenbacher s 1998 padding oracle attack  See this answer for better security    class MyEncryption        public  pubkey       public key here          public  privkey       private key here           public function encrypt  data                if  openssl public encrypt  data   encrypted   this- gt pubkey                data   base64 encode  encrypted           else             throw new Exception  Unable to encrypt data  Perhaps it is bigger than the key size              return  data             public function decrypt  data                if  openssl private decrypt base64 decode  data    decrypted   this- gt privkey                data    decrypted          else              data                return  data

User · Answer

No application written in 2017  or thereafter  that intends to incorporate serious cryptography should use RSA any more  There are better options for PHP public-key cryptography   There are two big mistakes that people make when they decide to encrypt with RSA    Developers choose the wrong padding mode  Since RSA cannot  by itself  encrypt very long strings  developers will often break a string into small chunks and encrypt each chunk independently  Sort of like ECB mode    The Best Alternative  sodium crypto box seal    libsodium    keypair   sodium crypto box keypair     publicKey   sodium crypto box publickey  keypair           encrypted   sodium crypto box seal       plaintextMessage       publicKey            decrypted   sodium crypto box seal open       encrypted       keypair      Simple and secure  Libsodium will be available in PHP 7 2  or through PECL for earlier versions of PHP  If you need a pure-PHP polyfill  get paragonie sodium compat   Begrudgingly  Using RSA Properly  The only reason to use RSA in 2017 is   I m forbidden to install PECL extensions and therefore cannot use libsodium  and for some reason cannot use paragonie sodium compat either    Your protocol should look something like this    Generate a random AES key  Encrypt your plaintext message with the AES key  using an AEAD encryption mode or  failing that  CBC then HMAC-SHA256  Encrypt your AES key  step 1  with your RSA public key  using RSAES-OAEP   MGF1-SHA256 Concatenate your RSA-encrypted AES key  step 3  and AES-encrypted message  step 2     Instead of implementing this yourself  check out EasyRSA   Further reading  Doing RSA in PHP correctly

[php] Encrypt and Decrypt text with RSA in PHP

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