[SCF high][easy] Reject zero-value and reused HTLC secrets

[karagozemin]

Goal

Prevent invalid or previously observed HTLC secrets from entering a new swap flow.

Acceptance criteria

• Reject all-zero secrets and hashlocks.
• Detect reuse within the coordinator order history.
• Add zero-value, reused, and valid-secret tests.

Complexity

High - small implementation, high cross-chain safety value.

[Horlarmmy]

@Horlarmmy has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi, I'd like to work on this issue. Kindly assign

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[OMGO-Code]

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Hi Maintainer! I'd like to work on this issue. I'm confident I can complete this task and submit a PR within 24 hours.

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[VeronicDev]

@VeronicDev has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi! I can fix this pls assign.

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[doncross03]

@doncross03 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Dear Team ,
Kindly assign this task to me ....am an expertise wen it come to delivery on time .....with my experience I will deliver promptly

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[simonpeters298]

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[TheFaith-Code]

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[Fayedamz]

@Fayedamz has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hello Maintainer, I'd love to work on this issue.

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[CollinsKRO]

@CollinsKRO has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi, I can fix this kindly assign.

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[Muyideen-js]

@Muyideen-js has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi, I can fix this

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[drips-wave]

Congratulations, @Horlarmmy! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on August 31, 2026.

🧑‍💻 @Horlarmmy: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

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