Cisco Cisco Email Security Appliance C680 User Guide
19-11
Cisco AsyncOS 9.0 for Email User Guide
Chapter 19 S/MIME Security Services
Verifying, Decrypting, or Decrypting and Verifying Incoming Messages using S/MIME
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Note
You can use AsyncOS S/MIME security services to verify, decrypt, or decrypt and verify outgoing and
incoming messages.
incoming messages.
S/MIME Verification and Decryption Workflow in AsyncOS for Email
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S/MIME Verification Workflow
The following process describes how AsyncOS performs S/MIME verification.
1.
Apply a hash algorithm to the message to create the message digest.
2.
Decrypt the digital signature using the public key of the sender's S/MIME certificate, and get the
message digest.
message digest.
3.
Compare the generated message digest with the message digest retrieved from the message. If the
message digests match, the message is verified.
message digests match, the message is verified.
S/MIME Decryption Workflow
The following process describes how AsyncOS performs S/MIME decryption.
1.
Decrypt the session key using the private key of the recipient's S/MIME certificate
2.
Decrypt the message body using the session key.