Digital Signature Registration
A digital signature is a mathematical scheme for demonstrating the authenticity of a digital message or document. A valid digital signature gives a recipient reason to believe that the message was created by a known sender, such that the sender cannot deny having sent the message authentication and non – repudiation that the message was not altered in transit integrity. Digital signatures are commonly used for software distribution, financial transactions, and in other cases where it is important to detect forgery or tampering
Digital signatures are often used to implement electronic signatures, 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 United States, India, Brazil, and members of the European Union, electronic signatures have legal significance.
Digital signatures employ a type of asymmetric cryptography. For messages sent through a no secure channel, a properly implemented digital signature gives the receiver reason to believe the message was sent by the claimed sender. Digital signatures are equivalent to traditional handwritten signatures in many respects, but properly implemented digital signatures are more difficult to forge than the handwritten type. Digital signature schemes, in the sense used here, are cryptographically based, and must be implemented properly to be effective. Digital signatures can also provide non – repudiation, meaning that the signer cannot successfully claim they did not sign a message, while also claiming their private key remains secret, further, some non-repudiation schemes offer a time stamp for the digital signature, so that even if the private key is exposed, the signature is valid. Digitally signed messages may be anything represents able as a bit string: examples include electronic mail, contracts, or a message sent via some other cryptographic protocol.
In their foundational paper, Goldwasser, Micali, and Rivest lay out a hierarchy of attack models against digital signatures.
- In a key-only attack, the attacker is only given the public verification key.
- In a known message attack, the attacker is given valid signatures for a variety of messages known by the attacker but not chosen by the attacker.
- In an adaptive chosen message attack, the attacker first learns signatures on arbitrary messages of the attacker's choice.
They also describe a hierarchy of attack results.
- A total break results in the recovery of the signing key.
- A universal forgery attack results in the ability to forge signatures for any message.
- A selective forgery attack results in a signature on a message of the adversary's choice.
- An existential forgery merely results in some valid message/signature pair not already known to the adversary.
The strongest notion of security, therefore, is security against existential forgery under an adaptive chosen message attack.
Class 2 Certificates are issued to Individuals, and Devices.
Class 2 validation procedures are based on the assurance that subscriber’s Distinguished Name (DN) is unique and unambiguous within MTNLTRUSTLINE Repository and that the identity of the Subscriber based on information provided by the Subscriber in the Certificate Application does not conflict with the information in a MTNLTRUSTLINE approved and well recognized business or consumer database(s) (Validating Database).
Class 2 Individual Certificates are appropriate for Digital Signatures, encryption, and electronic access control in transactions where proof of identity based on information in the Validating Database is sufficient.
Class 2 Device Certificates are appropriate for device authentication; message, software, and content integrity; and confidentiality encryption
