paraph n 1: a flourish added after or under your signature (originally to protect against forgery)
Paraph \Par"aph\, n. [F. paraphe, parafe, contr. fr. paragraphe.] A flourish made with the pen at the end of a signature. In the Middle Ages, this formed a sort of rude safeguard against forgery. --Brande & C. [1913 Webster]
Paraph \Par"aph\, v. t. [imp. & p. p. {Paraphed}; p. pr. & vb. n. {Paraphing}.] [Cf. F. parapher, parafer.] To add a paraph to; to sign, esp. with the initials. [1913 Webster]