This post has been republished via RSS; it originally appeared at: IIS Support Blog articles.
When you are using your .Net Core application to decrypt a string from a different machine than it was encrypted, you may run into the following exception:
Exception:
System.Security.Cryptography.CryptographicException: The payload was invalid.
at Microsoft.AspNetCore.DataProtection.Cng.CbcAuthenticatedEncryptor.DecryptImpl(Byte* pbCiphertext, UInt32 cbCiphertext, Byte* pbAdditionalAuthenticatedData, UInt32 cbAdditionalAuthenticatedData)
at Microsoft.AspNetCore.DataProtection.Cng.Internal.CngAuthenticatedEncryptorBase.Decrypt(ArraySegment`1 ciphertext, ArraySegment`1 additionalAuthenticatedData)
at Microsoft.AspNetCore.DataProtection.KeyManagement.KeyRingBasedDataProtector.UnprotectCore(Byte[] protectedData, Boolean allowOperationsOnRevokedKeys, UnprotectStatus& status)
at Microsoft.AspNetCore.DataProtection.KeyManagement.KeyRingBasedDataProtector.DangerousUnprotect(Byte[] protectedData, Boolean ignoreRevocationErrors, Boolean& requiresMigration, Boolean& wasRevoked)
at Microsoft.AspNetCore.DataProtection.KeyManagement.KeyRingBasedDataProtector.Unprotect(Byte[] protectedData)
at Microsoft.AspNetCore.DataProtection.DataProtectionCommonExtensions.Unprotect(IDataProtector protector, String protectedData)
Two things you will need to check:
1. Is the encryption key persists to a local path? - The key needs to be persisted to a shared location
2. SetApplicationName must be used to set an explicit application name. - If ApplicationName is not set, it will be generated a guid at runtime for different machines, and that will lead to the error above.
Code Example below:
services.AddDataProtection()
.ProtectKeysWithCertificate(x509Cert)
.UseCryptographicAlgorithms(
new AuthenticatedEncryptorConfiguration()
{
EncryptionAlgorithm = EncryptionAlgorithm.AES_256_CBC,
ValidationAlgorithm = ValidationAlgorithm.HMACSHA256
}
)
.PersistKeysToFileSystem(new System.IO.DirectoryInfo(Configuration.GetValue<string>("KeyLocation"))) //shared network folder for key location
.SetApplicationName("MyApplicationName")
.SetDefaultKeyLifetime(TimeSpan.FromDays(600));