9F45
Data Authentication CodeData Authentication Code is the one piece of card-specific data folded into what the Signed Static Application Data (93) signs, as named by the Static Data Authentication Tag List (9F4A) - its whole purpose is to make an otherwise purely static signature carry at least one value distinguishing this card from other cards sharing the same static data template. It's a small, 2-byte field, but it's what keeps SDA from being a single signature blindly reused, unchanged, across an entire batch of otherwise-identical cards. Because 9F45 itself doesn't change per transaction - it's set at personalization, not computed dynamically - it doesn't protect against a cloned card replaying a captured transaction the way DDA or CDA's per-transaction signing does; it only ensures each physical card's static data was genuinely signed by the issuer, which is the entire scope SDA was ever designed to cover. See EMV 4.4 Book 3.
Interactive decoder
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Binary (2): 1A2B
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Decoded example
Example value: 1A2B
Properties
| Tag | 9F45 |
|---|---|
| Name | Data Authentication Code |
| Format | Binary |
| Length | 2 bytes |
| Source | Card (ICC) |
| Templates | — |
| Books | EMV 4.4 Book 3 |
Frequently asked questions
- What is EMV tag 9F45?
- Data Authentication Code is the one piece of card-specific data folded into what the Signed Static Application Data (93) signs, as named by the Static Data Authentication Tag List (9F4A) - its whole purpose is to make an otherwise purely static signature carry at least one value distinguishing this card from other cards sharing the same static data template. It's a small, 2-byte field, but it's what keeps SDA from being a single signature blindly reused, unchanged, across an entire batch of otherwise-identical cards. Because 9F45 itself doesn't change per transaction - it's set at personalization, not computed dynamically - it doesn't protect against a cloned card replaying a captured transaction the way DDA or CDA's per-transaction signing does; it only ensures each physical card's static data was genuinely signed by the issuer, which is the entire scope SDA was ever designed to cover. See EMV 4.4 Book 3.
- What format and length does EMV tag 9F45 use?
- Tag 9F45 uses the Binary format and is normally 2 bytes long.
- Is tag 9F45 provided by the card or the terminal?
- Tag 9F45 (Data Authentication Code) is provided by the Card (ICC).
Sources
- EMV_v4.4_Book_3_Application_Specification, p. 144
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