A digital signature is a mathematical scheme for verifying the authenticity of digital messages or documents. A valid digital signature, where the prerequisites are satisfied, gives a recipient very strong reason to believe that the message was created by a known sender (authentication), and that the message was not altered in transit (integrity).
A digital signature is created when a digital message or document is transmitted, and signed by the corresponding digital private key (public key) of the sender, before it is made public. In unencrypted state, a digital signature is a digital certificate where the prerequisite is met, and before it is made public. The digital signature is valid and effective only while it is unencrypted.
The digital signature is created based on the public key, i.e. it is a digital certificate that is signed with a public key. Digital certificates with a corresponding private key, are created by encrypting the corresponding public key, and signing the result with the corresponding private key.
The digital signature, while in unencrypted state, gives a sender and recipient a powerful digital proof that the message has not been altered in transit. And in encrypted state, the digital signature is the strong link between sender and recipient. The sender digitally signs the decrypted message with the corresponding private key, and stores the signed digital certificate in a secure location.
The decryption of the encrypted message reveals the corresponding public key of the sender, and the corresponding private key of the recipient. This provides the sender and recipient with an unreadable copy of the encrypted message, and the digital signature is no longer necessary. Since the private key of the corresponding private key of the sender is known, it is no longer necessary to store the corresponding digital signature in the secure location, and can be distributed and used without losing the original decrypted message or information.
The signer of the digital message that is sent encrypted with a public key, can be any authenticated user, and the recipient that receives the encrypted message can be any recipient, in any network.
The digital signature, having both sender and recipient’s public keys, can be used for encryption and decryption purposes, and is often used in authentication. The digital signature, being digital proof, provides robust security in case of decryption.
A digital signature is one of the strongest security mechanisms used in encryption today. The confidentiality of an encrypted message may be ensured by using a digital signature. Since the digital signature is not stored in any secure location, an unauthorized party has no way of decrypting the message without the digital proof of the message. If the sender and recipient public keys are known, it is possible to perform a signature verification on the decrypted message, so that only the signed message is decrypted.
An encrypted message has no possibility of being decrypted with the help of a non-secure process.
A public key encryption is created using a public key encryption with the private key of the sender and the public key stored in the secure location. The private key may be needed for decryption. An encrypted message may be decrypted by applying a decryption algorithm. A public key algorithm is used for digital signature, public encryption and public decryption. The sender and the recipient public keys are used for encryption and decryption.