Verify a Password against an Argon2 Hash

Demonstrates Crypt2.Argon2VerifyPassword, which verifies a password against a PHC-format Argon2 hash string. The cost parameters are read from the hash string, so none need to be supplied.

-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    DECLARE @sTmp0 nvarchar(4000)
    DECLARE @crypt int
    EXEC @hr = sp_OACreate 'Chilkat.Crypt2', @crypt OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    --  The password should come from a secure source rather than being hard-coded.
    DECLARE @password nvarchar(4000)
    SELECT @password = 'correct horse battery staple'

    --  A PHC-format Argon2 hash string previously produced by Argon2HashPassword.  All cost options
    --  (variant, version, memory cost, iterations, parallelism, salt, hash length) are read from this
    --  string, so none need to be supplied.
    DECLARE @phcHash nvarchar(4000)
    SELECT @phcHash = '$argon2id$v=19$m=65536,t=3,p=1$c29tZXJhbmRvbXNhbHQ$3fJ7v1qKcVJ0lHqXjBQZ8mYm3sNTfSPRt0bqDl9kEyM'

    --  Verify the password.  Pass an empty options string when no secret (pepper) or ad was used.
    --  The method returns one of three values:  1 = the password matched, 0 = it did not match, and
    --  -1 = the verification could not be performed (the hash string was invalid or unusable).
    --  Always test for a match with == 1.
    DECLARE @verifyResult int
    EXEC sp_OAMethod @crypt, 'Argon2VerifyPassword', @verifyResult OUT, @password, '', @phcHash
    IF @verifyResult = 1
      BEGIN

        PRINT 'The password is verified.'
      END
    ELSE
      BEGIN
        IF @verifyResult = 0
          BEGIN

            PRINT 'The password does not match.'
          END
        ELSE
          BEGIN

            EXEC sp_OAGetProperty @crypt, 'LastErrorText', @sTmp0 OUT
            PRINT 'The verification could not be performed: ' + @sTmp0
          END
      END

    EXEC @hr = sp_OADestroy @crypt


END
GO