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(Xojo Plugin) RSA Encryption -- Same Key Different ResultsThe RSA encryption algorithm produces different results for each call, even when encrypting the same data with the same key. Decryption however, will produce the correct results. This example demonstrates. *** The reason this occurs is that RSA encryption uses PKCS1 v1.5 padding, and this padding scheme uses random bytes. It is random bytes in the padding that causes the result to be different each time. Note: This example requires Chilkat v11.0.0 or greater.
Dim success As Boolean success = False // This example assumes the Chilkat API to have been previously unlocked. // See Global Unlock Sample for sample code. Dim rsa As New Chilkat.Rsa Dim pubKeyXml As String pubKeyXml = "<RSAPublicKey><Modulus>xxyv1RDPU0MvfFIIa98HppXdcuI7zSu8uIqyGAy/VoxPvxZFX0acajznvjVRHipHbpcO6ryo2LwXUPf89qOqLb3Qd1lfD2ZnH+TQ6MZXNxfFRxTpTUd+tTR4EBYpd2t6kzq8ZRJYLdlviaMQQqUEwR54k7Op5HJYVKUcHIkP1xE=</Modulus><Exponent>AQAB</Exponent></RSAPublicKey>" Dim privKeyXml As String privKeyXml = "<RSAKeyValue><Modulus>xxyv1RDPU0MvfFIIa98HppXdcuI7zSu8uIqyGAy/VoxPvxZFX0acajznvjVRHipHbpcO6ryo2LwXUPf89qOqLb3Qd1lfD2ZnH+TQ6MZXNxfFRxTpTUd+tTR4EBYpd2t6kzq8ZRJYLdlviaMQQqUEwR54k7Op5HJYVKUcHIkP1xE=</Modulus><Exponent>AQAB</Exponent><P>4cpW9fvG99Jsz8/AO7PDHTl+pPRAglksrR2kClLV2g9DEeFe/bvmCxLUgMCJ+0eGQ1zA6aA7McKr13zTQ7jKpQ==</P><Q>4cCS/kFlq/P1ExF37Fkh4pCodOEGutepLEG7Q/KljT3ZGlAY+2l8fGu4f+hrkUuGoFl7NOMaJflULoPIgQaq/Q==</Q><DP>lkjcSsvzqh3YKRXJiLNkyf3rypV8noYGU4+oEOsDxilkZfFRDafUPUiiQrRk4ui/d/SzvozU+ZDuWfaOk8PatQ==</DP><DQ>SYCD25i7W8Mwdibn3uIecEAdOQDTSh5RjIFSUYs9b8FFYJXXrHPp/jCsf6jS7RmkGa1Iui1/JAIL8KEjtS7QmQ==</DQ><InverseQ>EDAJa3TpNdPQ3GIdBpnTgFTQY5A60DcszsUW/iCYoXQdPVJ9BLBxVTe9jiLzGuNuzLkVBwQlCy0Bf84hACRV9A==</InverseQ><D>cMFdDYKkddlRNczaugOmOH8b1egpx2liSPs6GYZ2gFObAXJiPK8m+r6c2ckls7hrlUP0DZhi4cG6Tn7xANb0Ek17P7QquVhQYOmFy/YHzm+IJbcwwq7pJHhZBhtcjyXqfUZ+BADGE//GQbrSVwVltpOj5KcxG88NAprLn2MMxfE=</D></RSAKeyValue>" Dim pubKey As New Chilkat.PublicKey success = pubKey.LoadFromString(pubKeyXml) If (success = False) Then System.DebugLog(pubKey.LastErrorText) Return End If Dim privKey As New Chilkat.PrivateKey success = privKey.LoadXml(privKeyXml) If (success = False) Then System.DebugLog(privKey.LastErrorText) Return End If success = rsa.UsePublicKey(pubKey) If (success = False) Then System.DebugLog(rsa.LastErrorText) Return End If // Encrypt a string and return the encrypted data base64-encoded: rsa.EncodingMode = "base64" Dim plainText As String plainText = "RSA gives different results with each call, weird but OK" Dim usePrivateKey As Boolean usePrivateKey = False Dim encryptedStr1 As String encryptedStr1 = rsa.EncryptStringENC(plainText,usePrivateKey) System.DebugLog(encryptedStr1) // Do it again. The results are different... Dim encryptedStr2 As String encryptedStr2 = rsa.EncryptStringENC(plainText,usePrivateKey) System.DebugLog(encryptedStr2) // Now decrypt both strings, and the results are correct // in both cases: Dim rsa2 As New Chilkat.Rsa success = rsa2.UsePrivateKey(privKey) If (success = False) Then System.DebugLog(rsa.LastErrorText) Return End If rsa2.EncodingMode = "base64" usePrivateKey = True Dim decryptedStr1 As String decryptedStr1 = rsa2.DecryptStringENC(encryptedStr1,usePrivateKey) System.DebugLog(decryptedStr1) Dim decryptedStr2 As String decryptedStr2 = rsa2.DecryptStringENC(encryptedStr2,usePrivateKey) System.DebugLog(decryptedStr2) |
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