[Wiki] 什么是数字签名

Digital signature

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This article concerns cryptographic signatures. For signatures in digital form, see .

A digital signature or digital signature scheme is a type of used to simulate the security properties of a handwritten on paper. Digital signature schemes normally give two algorithms, one for signing which involves the user's secret or , and one for verifying signatures which involves the user's . The output of the signature process is called the "digital signature."

# 注释 ：数字签名或者数字签名方案是“非对称加密”的一种，用于模仿日常在纸质上的签名。

# 数字签名方案一般给出两种算法 ：

#     -）1、一个调用户的 private key ，用于进行签名。

#     -）2、一个调用用户的公钥，用于校验签名。

# 签名过程的输出称为“数字签名”

A signature provides of a "message". Messages may be anything, from to a , or even a message sent in a more complicated . Digital signatures are used to create (PKI) schemes in which a user's public key (whether for , digital signatures, or any other purpose) is tied to a user by a issued by a . PKI schemes attempt to unbreakably bind user information (name, address, phone number, etc.) to a public key, so that public keys can be used as a form of .

# 注释 ：一个签名提供对一个消息的“认证”。消息可以是任何内容，从电子邮件到合同，甚至是其他更加复杂的数据。

# 数字签名用于建立 PKI 方案，在该方案中，一个用户的身份和一个数字证书绑定在一起，证书由 CA 颁发。PKI 方案的目的是用公钥来表示一个用户的身份

Digital signatures are often used to implement , a broader term that refers to any electronic data that carries the intent of a signature, but not all electronic signatures use digital signatures. In some countries, including the , and in the , electronic signatures have legal significance. However, laws concerning electronic signatures do not always make clear their applicability towards cryptographic digital signatures, leaving their legal importance somewhat unspecified.

# 注释 ：数字签名一般是用于实现“电子签名”，电子签名是一个意义上更加广泛的术语，不仅仅是数字签名而已，可以包括指纹等实现方式

A digital signature scheme typically consists of three algorithms:

# 注释 ：一个数字签名方案应该包括下面3种算法 ：

#     -）1、key generation （G 算法）随机生成一个 key 对（PK,SK）。PK 是校验用，SK 是签名用

#     -）2、算法 S ：输入一个消息 m ，以及 SK ，产生一个签名 σ

#     -）3、算法 V ：输入一个消息 m，以及 PK，一个签名 σ ，得出校验结果（接受/拒绝）

        A algorithm G that randomly produces a "key pair" (PK, SK) for the signer. PK is the verifying key, which is to be public, and SK is the signing key, to be kept private.

        A signing algorithm S, that on input of a message m and a signing key SK, produces a signature σ.

        A signature verifying algorithm V, that on input a message m, a verifying key PK, and a signature σ, either accepts or rejects.

Two main properties are required. First, signatures computed honestly should always verify. That is, V should accept (m, PK, S (m, SK)) where SK is the secret key related to PK, for any message m. Secondly, it should be hard for any adversary, knowing only PK, to create valid signature(s)

# 注释 ：其中 V 算法中的 σ=S（m，SK）