SQL Server

RSA Encrypt and Decrypt Strings

See more RSA Examples

_LANGUAGE_ sample code to RSA public-key encrypt and decrypt strings using public and private keys. 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

    -- This example assumes the Chilkat API to have been previously unlocked.
    -- See Global Unlock Sample for sample code.

    DECLARE @rsa int
    EXEC @hr = sp_OACreate 'Chilkat.Rsa', @rsa OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    -- This example also generates the public and private
    -- keys to be used in the RSA encryption.
    -- Normally, you would generate a key pair once,
    -- and distribute the public key to your partner.
    -- Anything encrypted with the public key can be
    -- decrypted with the private key.  The reverse is 
    -- also true: anything encrypted using the private
    -- key can be decrypted using the public key.

    -- Generate a 2048-bit key.  Chilkat RSA supports
    -- key sizes ranging from 512 bits to 4096 bits.
    DECLARE @privKey int
    EXEC @hr = sp_OACreate 'Chilkat.PrivateKey', @privKey OUT

    EXEC sp_OAMethod @rsa, 'GenKey', @success OUT, 2048, @privKey
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @rsa, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @rsa
        EXEC @hr = sp_OADestroy @privKey
        RETURN
      END

    DECLARE @pubKey int
    EXEC @hr = sp_OACreate 'Chilkat.PublicKey', @pubKey OUT

    EXEC sp_OAMethod @privKey, 'ToPublicKey', @success OUT, @pubKey

    DECLARE @plainText nvarchar(4000)
    SELECT @plainText = 'Encrypting and decrypting should be easy!'

    -- Start with a new RSA object to demonstrate that all we
    -- need are the keys previously exported:
    DECLARE @rsaEncryptor int
    EXEC @hr = sp_OACreate 'Chilkat.Rsa', @rsaEncryptor OUT

    -- Encrypted output is always binary.  In this case, we want
    -- to encode the encrypted bytes in a printable string.
    -- Our choices are "hex", "base64", "url", "quoted-printable".
    EXEC sp_OASetProperty @rsaEncryptor, 'EncodingMode', 'hex'

    -- We'll encrypt with the public key and decrypt with the private
    -- key.
    EXEC sp_OAMethod @rsaEncryptor, 'UsePublicKey', @success OUT, @pubKey

    DECLARE @usePrivateKey int
    SELECT @usePrivateKey = 0
    DECLARE @encryptedStr nvarchar(4000)
    EXEC sp_OAMethod @rsaEncryptor, 'EncryptStringENC', @encryptedStr OUT, @plainText, @usePrivateKey

    PRINT @encryptedStr

    -- Now decrypt:
    DECLARE @rsaDecryptor int
    EXEC @hr = sp_OACreate 'Chilkat.Rsa', @rsaDecryptor OUT

    EXEC sp_OASetProperty @rsaDecryptor, 'EncodingMode', 'hex'
    EXEC sp_OAMethod @rsaDecryptor, 'UsePrivateKey', @success OUT, @privKey

    SELECT @usePrivateKey = 1
    DECLARE @decryptedStr nvarchar(4000)
    EXEC sp_OAMethod @rsaDecryptor, 'DecryptStringENC', @decryptedStr OUT, @encryptedStr, @usePrivateKey


    PRINT @decryptedStr

    EXEC @hr = sp_OADestroy @rsa
    EXEC @hr = sp_OADestroy @privKey
    EXEC @hr = sp_OADestroy @pubKey
    EXEC @hr = sp_OADestroy @rsaEncryptor
    EXEC @hr = sp_OADestroy @rsaDecryptor


END
GO