Indicates how the cardholder was identified at the time of the transaction. For MasterCard, known as the Cardholder Authentication Method.

Possible values for Visa:

• <Space>: Not specified
• 1: Signature
• 2: PIN
• 3: Unattended terminal; no PIN pad
• 4: Mail/Telephone or Electronic Commerce

Possible values for MasterCard:

• 0: Not authenticated
• 1: PIN
• 2: Electronic signature analysis
• 5: Manual signature verification
• 6: Other manual verification (such as a driver’s license number)
• 9: Unknown; data not available
• S: Other systematic verification