不同於傳統數位簽章具有可公開驗證性，指定驗證者簽章只允許被指定的驗證者可以驗證簽章的正確性，確保了簽章者的隱私性而被廣泛的應用於諸多系統上。本論文的研究集中在數個指定驗證者簽章以及其變形簽章的主題上。 在授權性（Delegatability）的研究上，首先，我們對於指定驗證者簽章的授權性做分類，使其能適合不同的指定驗證者簽章系統。接下來，我們會指出兩個現存的指定驗證著簽章系統TOO系統和LSMP系統在授權性上的缺陷。 觀察到可擷取式簽章系統（Content Extraction Signature）有驗證者間共謀的缺陷存在，我們使用指定驗證者簽章的概念，提出了一個可指定驗證者的可擷取式簽章系統，解決了這個問題。 本論文的最後一部分關注的重點在建構一個新的受限制之廣義指定驗證者簽章系統（Restricted Universal Designated Verifier Signature），在指出了黃等人簽章系統的缺陷後，我們提出了一個新的建構方式以及簽章系統。 Designated verifier signatures allow only a certain recipient can be convinced about the validity of a digital signature which protect the signer's privacy and is very useful in many applications. In this thesis, our research focus on several specific topics of DVS and it's variant schemes. On the research of delegatability, first, we classify this property to fit difierent DVS variant schemes. Afterwards, two existing DVS schemes: TOO strong-DVS scheme and LSMP constant-size multi-DVS scheme are shown to be delegatable. Observing that content extraction signatures are vulnerable on the verifier conspiracy problem. By modifying the original content extraction signature scheme with the concept of DVS, a content extraction signature scheme which can be designated to a certain recipient is proposed. In the last part of our thesis, our objective is to construct a new restricted universal designated verifier signature. After point out the major problems of Huang et al.'s scheme, a new restricted universal designated verifier signature scheme is proposed.
