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  1. Public Function rsaEncryptBytes(abMessage() As Byte, strPublicKey As String) As Variant
  2. ' Uses RSA public key to encrypt a message using default PKCS-1-v1.5 encoding method
  3. ' Returns the resulting ciphertext as an array of bytes passed as a Variant, 
  4. ' or an empty value on error.
  5.     Dim lngRet As Long
  6.     Dim abDummy(0) As Byte
  7.     Dim abBlock() As Byte
  8.     ' All lengths are in octets (i.e. 8-bit bytes)
  9.     Dim nkLen As Long   ' length, k, of RSA key modulus
  10.     Dim nmLen As Long   ' length of message, M
  11.  
  12.     rsaEncryptBytes = abDummy
  13.  
  14.     ' Compute lengths
  15.     nmLen = BytesLength(abMessage)
  16.     nkLen = RSA_KeyBytes(strPublicKey)
  17.  
  18.     ' Encode using EME
  19.     ReDim abBlock(nkLen - 1)
  20.     lngRet = RSA_EncodeMsg(abBlock(0), nkLen, abMessage(0), nmLen, PKI_EME_DEFAULT)
  21.     If lngRet <> 0 Then Exit Function
  22.  
  23.     ' Encrypt using RSA public key
  24.     lngRet = RSA_RawPublic(abBlock(0), nkLen, strPublicKey, 0)
  25.     If lngRet <> 0 Then Exit Function
  26.  
  27.     ' Return ciphertext block
  28.     rsaEncryptBytes = abBlock
  29. End Function
  30.  
  31. Public Function rsaDecryptBytes(abCipher() As Byte, strPrivateKey As String) As Variant
  32. ' Decrypts RSA-encrypted ciphertext using the RSA private key passed as a string.
  33. ' Returns the resulting message as an array of bytes passed as a Variant, 
  34. ' or an empty value on error.
  35.     Dim abDummy(0) As Byte
  36.     Dim abMessage() As Byte
  37.     Dim lngRet As Long
  38.     Dim abBlock() As Byte
  39.     Dim nkLen As Long   ' length, k, of RSA key modulus
  40.     Dim nmLen As Long   ' length of message, M
  41.  
  42.     rsaDecryptBytes = abDummy
  43.  
  44.     nkLen = BytesLength(abCipher)
  45.     If nkLen <> RSA_KeyBytes(strPrivateKey) Then
  46.         Exit Function
  47.     End If
  48.     abBlock = abCipher
  49.  
  50.     ' Decrypt
  51.     lngRet = RSA_RawPrivate(abBlock(0), nkLen, strPrivateKey, 0)
  52.     If lngRet <> 0 Then
  53.         Exit Function
  54.     End If
  55.  
  56.     ' Now we decode according to EME-PKCS-V1_5-DECODE
  57.     nmLen = RSA_DecodeMsg(0, 0, abBlock(0), nkLen, PKI_EME_DEFAULT)
  58.     If nmLen <= 0 Then Exit Function
  59.     ReDim abMessage(nmLen - 1)
  60.     nmLen = RSA_DecodeMsg(abMessage(0), nmLen, abBlock(0), nkLen, PKI_EME_DEFAULT)
  61.  
  62.     ' Output M.
  63.     rsaDecryptBytes = abMessage
  64.  
  65. End Function
  66.  
  67. Private Function BytesLength(abBytes() As Byte) As Long
  68. ' General function to return length of byte array
  69.     ' Trap error if array is empty
  70.     On Error Resume Next
  71.     BytesLength = UBound(abBytes) - LBound(abBytes) + 1
  72. End Function
  73.  
  74.  
  75. Public Function TestEncryptAndDecrypt()
  76.     Dim abMessage() As Byte
  77.     Dim abBlock() As Byte
  78.     Dim strPublicKey As String
  79.     Dim strPubKeyFile As String
  80.     strPubKeyFile = "mykeypub.bin"
  81.  
  82.     ' Convert ANSI text to bytes
  83.     abMessage = StrConv("Hello world!", vbFromUnicode)
  84.  
  85.     Debug.Print "M (ansi): " & StrConv(abMessage, vbUnicode)
  86.     Debug.Print "M (hex):  " & cnvHexStrFromBytes(abMessage)
  87.  
  88.     ' Read in the public key from file
  89.     strPublicKey = rsaReadPublicKey(strPubKeyFile)
  90.     If Len(strPublicKey) = 0 Then
  91.         MsgBox "Cannot read RSA public key file '" & strPubKeyFile & "'", vbCritical
  92.         Exit Function
  93.     End If
  94.  
  95.     ' Call encrypt function
  96.     abBlock = rsaEncryptBytes(abMessage, strPublicKey)
  97.     Debug.Print "CT: " & cnvHexStrFromBytes(abBlock)
  98.  
  99.     ' DECRYPTION
  100.     Dim strPrivateKey As String
  101.     Dim strPriKeyFile As String
  102.     Dim abPlain() As Byte
  103.     strPriKeyFile = "mykeypri.bin"
  104.  
  105.     ' Read in the private key from file
  106.     strPrivateKey = rsaReadPrivateKey(strPriKeyFile, "password")
  107.     If Len(strPrivateKey) = 0 Then
  108.         MsgBox "Cannot read RSA private key file '" & strPriKeyFile & "'", vbCritical
  109.         Exit Function
  110.     End If
  111.  
  112.     ' Call decrypt function
  113.     abPlain = rsaDecryptBytes(abBlock, strPrivateKey)
  114.     Debug.Print "PT (hex) : " & cnvHexStrFromBytes(abPlain)
  115.     Debug.Print "PT (ansi): " & StrConv(abPlain, vbUnicode)
  116.  
  117. End Function
  118.  
Runtime error #stdin #stdout #stderr 0.01s 2736KB
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Standard input is empty
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Standard output is empty
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Fatal error: exception Unlambda.ParseError
https://ideone.com/0EigdA
language:
Unlambda (unlambda 0.1.4.2)
created:
11 years ago
visibility:
public

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