[FEATURE] : Implement Crypto Utilities Package

[wheval]

Implement Crypto Utilities Package

Description:
Implement @ancore/crypto with key generation, mnemonic support, encryption/decryption, and transaction signing. This is security-critical — keys must never leave the device.

Context:
The package is currently a stub (CRYPTO_VERSION export only). Dependencies @noble/ed25519 and @noble/hashes are already in package.json. The wallet needs this for onboarding (mnemonic generation), key storage (encryption), and transaction signing.

Requirements:

• Implement generateMnemonic() — BIP39 12-word mnemonic
• Implement validateMnemonic(mnemonic) — validate BIP39 mnemonic
• Implement deriveKeypairFromMnemonic(mnemonic, index) — derive Stellar keypair from mnemonic
• Implement encryptSecretKey(secretKey, password) — AES-256-GCM encryption with PBKDF2 key derivation
• Implement decryptSecretKey(encrypted, password) — decrypt stored secret key
• Implement signTransaction(tx, keypair) — local transaction signing
• Implement verifySignature(message, signature, publicKey)
• Password strength validation
• Secure random salt/IV generation per operation
• Unit tests for all functions (100% coverage target)

Files to Create:

• packages/crypto/src/mnemonic.ts
• packages/crypto/src/encryption.ts
• packages/crypto/src/signing.ts
• packages/crypto/src/password.ts
• packages/crypto/src/index.ts (update)
• packages/crypto/src/__tests__/mnemonic.test.ts
• packages/crypto/src/__tests__/encryption.test.ts
• packages/crypto/src/__tests__/signing.test.ts

Dependencies:

• @stellar/stellar-sdk
• @noble/hashes
• @noble/ed25519
• bip39

Definition of Done:

• All crypto functions implemented and exported
• Encryption round-trip works (encrypt → decrypt = original)
• Mnemonic → keypair derivation is deterministic
• Tests pass with 100% coverage
• No secret keys logged or transmitted

Labels: crypto, security, foundation, critical
Estimated Effort: 3–5 days
Priority: Critical — blocks account-abstraction and storage manager

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[Sundayabel222]

@Sundayabel222 has applied to work on this issue as part of the Stellar Wave Program's 2nd wave.

Gm Gm

Pls I will really Love to Wok on this Issues with the little time we have left

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[romeoscript]

@romeoscript has applied to work on this issue as part of the Stellar Wave Program's 2nd wave.

Hi , maintainer i'd like to work on this issue , i'm a 10x engineer and will deliver in few hours

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[devJaja]

@devJaja has applied to work on this issue as part of the Stellar Wave Program's 2nd wave.

Hello, I’m a smart contract and full-stack developer actively contributing to open-source ecosystems. I’ve worked on 30+ projects across the ecosystem, with hands-on experience in Solidity, Cairo, Soroban, JavaScript, TypeScript, Rust, and building on the Stellar ecosystem. I’m passionate about delivering secure and scalable blockchain systems and would love the opportunity to support and contribute to this issue.

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