SQL Server

RSA Encrypt/Decrypt Bytes

See more RSA Examples

Demonstrates how to RSA encrypt and decrypt byte data. SQL Server

-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    -- Important: Do not use nvarchar(max).  See the warning about using nvarchar(max).
    DECLARE @sTmp0 nvarchar(4000)
    DECLARE @success int
    SELECT @success = 0

    -- The RSA public key is used for encryption, and the private key for decryption.

    -- The public key's role is to make encryption accessible to anyone while ensuring that
    -- only the private key holder can decrypt the messages.
    -- The public key is designed to be widely distributed so anyone can use it to encrypt messages
    -- intended for the owner of the private key.

    -- Load our 2048-bit RSA public key.
    DECLARE @pubKey int
    EXEC @hr = sp_OACreate 'Chilkat.PublicKey', @pubKey OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    -- In all Chilkat methods expecting a path, you pass either absolute or relative paths.
    EXEC sp_OAMethod @pubKey, 'LoadFromFile', @success OUT, 'qa_data/rsaKeys/myTestRsaPublic.pem'
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @pubKey, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @pubKey
        RETURN
      END

    DECLARE @rsa int
    EXEC @hr = sp_OACreate 'Chilkat.Rsa', @rsa OUT

    -- Tell RSA to use the public key.
    EXEC sp_OAMethod @rsa, 'UsePublicKey', @success OUT, @pubKey

    -- RSA encryption is for small amounts of data, on the order of 200 bytes or less.
    -- The maximum number of bytes that can be RSA encrypted depends
    -- on the RSA key size and padding scheme (OAEP padding vs PKCS#1 v1.5 padding).
    -- For specific limits, see: RSA Encryption Maximum Number of Bytes

    -- A typical use for RSA is to encrypt symmetric encryption keys, such as an AES key.
    DECLARE @prng int
    EXEC @hr = sp_OACreate 'Chilkat.Prng', @prng OUT

    EXEC sp_OAMethod @prng, 'GenRandomBytes', @keyBytes OUT, 32

    EXEC sp_OAMethod @rsa, 'EncryptBytes', @encBytes OUT, @keyBytes, 0

    -- ------------------------------------------------------------------------------------------------------------------------
    -- Let's decrypt, which requires the matching private key...

    -- Load the matching 2048-bit RSA private key.
    DECLARE @privKey int
    EXEC @hr = sp_OACreate 'Chilkat.PrivateKey', @privKey OUT

    DECLARE @password nvarchar(4000)
    SELECT @password = 'secret'
    EXEC sp_OAMethod @privKey, 'LoadAnyFormatFile', @success OUT, 'qa_data/rsaKeys/myTestRsaPrivate.pem', @password
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @privKey, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @pubKey
        EXEC @hr = sp_OADestroy @rsa
        EXEC @hr = sp_OADestroy @prng
        EXEC @hr = sp_OADestroy @privKey
        RETURN
      END

    -- Tell the RSA object to use the private key.
    EXEC sp_OAMethod @rsa, 'UsePrivateKey', @success OUT, @privKey

    EXEC sp_OAMethod @rsa, 'DecryptBytes', @decBytes OUT, @encBytes, 1
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @rsa, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @pubKey
        EXEC @hr = sp_OADestroy @rsa
        EXEC @hr = sp_OADestroy @prng
        EXEC @hr = sp_OADestroy @privKey
        RETURN
      END


    PRINT 'Success.'

    EXEC @hr = sp_OADestroy @pubKey
    EXEC @hr = sp_OADestroy @rsa
    EXEC @hr = sp_OADestroy @prng
    EXEC @hr = sp_OADestroy @privKey


END
GO