![]() ![]() Printf("Bad Key from verify signature function.\n") Printf("Bad Hash from verify signature function.\n") Printf("Bad Flags from verify signature function.\n") Printf("The parameter from verify signature " Printf("The handle from verify signature is not valid." \ Printf("The message type is not valid.\n") Printf("The hash value is not correct.\n") Printf("An error encountered encoding or decoding.\n") Printf("Message does not contain an expected " _ftprintf(stderr, TEXT("Program terminating. _ftprintf(stderr, TEXT("Error number %x.\n"), GetLastError()) _ftprintf(stderr, TEXT("An error occurred in the program. Void DecodeMessage(PCRYPT_DATA_BLOB pEncodedData, -īOOL EncodeMessage(PCRYPT_DATA_BLOB pEncodedData, #define MY_ENCODING_TYPE (PKCS_7_ASN_ENCODING | X509_ASN_ENCODING) Example of encoding and decoding a signed message. Code for this and other auxiliary functions is also listed under General_Purpose_Functions. ![]() Code for this function is included with the sample. This example uses the function MyHandleError. Freeing memory, closing certificate stores, and freeing certificate context.įor an example of how to perform these similar operations using a stream callback, see Example C Program: Encoding and Decoding a Message Using a Stream.Verifying a message's signature using CryptMsgControl.Using CertGetSubjectCertificateFromStore to get the certificate of the message's signer.Opening a certificate store in memory with CertOpenStore using the message received and decoded.Decoding the message using CryptMsgGetParam.Adding the encoded BLOB to the message to be decoded by using CryptMsgUpdate.Opening a message for decoding with CryptMsgOpenToDecode.This example illustrates the following tasks and CryptoAPI functions for decoding a message and verifying the signature: Signing and encoding a message with CryptSignMessage. ![]() Initializing a CRYPT_SIGN_MESSAGE_PARA structure to be used in a call to CryptSignMessage.Getting and printing a certificate's subject name using CertGetNameString.Retrieving a certificate with a specific subject name using CertFindCertificateInStore.Opening a certificate store using CertOpenStore.This example illustrates the following tasks and CryptoAPI functions for encoding a message: Because the message is signed with the sender's private key, when the receiver of the message decrypts the signature with the sender's public key (available from the certificate that is sent along with the message), the receiver can be sure that the message was sent by the person or entity associated with the certificate and that the message was not changed after it was signed. Rather it ensures the authenticity of the message. Signing and encoding a message does not ensure privacy for that message. The two processes have been combined here to show both procedures working. The decoding example would receive the encoded message, decode it, and verify the signature. The encoding example would create the encoded message, save it to a disk file or in some other way send it to another user. The two operations would usually be in separate programs. The following example combines signing and encoding a message, and decoding a signed message and verifying the signature. ![]()
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