SIMD-0453: Ed25519 Precompile Signature Verification with SIMD376/ZIP-215

[zz-sol]

Blocked by: #376

Description:

This SIMD specifies the Ed25519 precompile portion of the ZIP-215 transition described in SIMD-0376.

Summary:

• A new SIMD proposal describing an Ed25519 precompile verification-mode flag to support strict_verify and ZIP-215 with a feature gate.
• Introduces a dedicated feature gate (ed25519_precompile_verify_strict_to_zip215) separate from SIMD-0376
• Fully backwards compatible: all signatures valid under strict_verify remain valid

Relationship to SIMD-0376:

SIMD-0376 covers transaction signatures, gossip, and shreds. This SIMD refines that scope by providing the concrete specification and independent feature gate for the precompile, allowing staged rollout and isolated testing.

[simd-bot]

Hello zz-sol! Welcome to the SIMD process. By opening this PR you are affirming that your SIMD has been thoroughly discussed and vetted in the SIMD discussion section. The SIMD PR section should only be used to submit a final technical specification for review. If your design / idea still needs discussion, please close this PR and create a new discussion here.

This PR requires the following approvals before it can be merged:

• At least one approval from a Anza team member: t-nelson, sakridge, or bw-solana
• At least one approval from an Firedancer team member: ptaffet-jump, topointon-jump, 0x0ece, lidatong, or ripatel-fd

Once all requirements are met, you can merge this PR by commenting /merge.

[zz-sol]

CI Error:

Error: Error: {"/home/runner/work/solana-improvement-documents/solana-improvement-documents/proposals/XXXX-ed25519-precompile-zebra.md":[{"lineNumber":14,"ruleNames":["front-matter-has-simd"],"ruleDescription":"Metadata simd is a 4 digit numerical string","ruleInformation":null,"errorDetail":"Front matter simd must be a numerical string","errorContext":null,"errorRange":null,"fixInfo":null},{"lineNumber":14,"ruleNames":["front-matter-has-title"],"ruleDescription":"Proposal front matter should include a title no longer than 45 characters","ruleInformation":null,"errorDetail":"Metadata title should be no longer than 45 characters","errorContext":null,"errorRange":null,"fixInfo":null}]}
Error: Process completed with exit code 1.

Will address once #376 is merged and this get's its own id.