Question

A financial institution sends high-value payment instructions to a correspondent bank electronically. Management wants assurance that a sender cannot later deny having authorized a transaction and that the instruction was not altered in transit. Which control BEST meets both requirements?

Accepted Answer

Applying a digital signature created with the sender's private key over a hash of the instruction

Answer

Encrypting the payment instruction with the recipient's public key

Answer

Transmitting the instruction over a TLS-secured VPN tunnel between the two banks

Answer

Requiring both parties to share a symmetric session key derived at connection time