feat: add Keypair class and deprecate Account (#17098)

* feat: add Keypair class and deprecate Account

* chore: fix lint issues

* chore: rename TransactionSigner to Signer

web3.js/src/keypair.ts

@@ -0,0 +1,84 @@
+import * as nacl from 'tweetnacl';
+import type {SignKeyPair} from 'tweetnacl';
+
+import {PublicKey} from './publickey';
+
+/**
+ * Keypair signer interface
+ */
+export interface Signer {
+  publicKey: PublicKey;
+  secretKey: Uint8Array;
+}
+
+/**
+ * An account keypair used for signing transactions.
+ */
+export class Keypair {
+  /**
+   * @internal
+   *
+   * Create a new keypair instance from a {@link SignKeyPair}.
+   *
+   * @param keypair ed25519 keypair
+   */
+  constructor(private keypair: SignKeyPair) {}
+
+  /**
+   * Generate a new random keypair
+   */
+  static generate(): Keypair {
+    return new Keypair(nacl.sign.keyPair());
+  }
+
+  /**
+   * Create a keypair from a raw secret key byte array.
+   *
+   * This method should only be used to recreate a keypair from a previously
+   * generated secret key. Generating keypairs from a random seed should be done
+   * with the {@link Keypair.fromSeed} method.
+   *
+   * @throws error if the provided secret key is invalid and validation is not skipped.
+   *
+   * @param secretKey secret key byte array
+   * @param options: skip secret key validation
+   */
+  static fromSecretKey(
+    secretKey: Uint8Array,
+    options?: {skipValidation?: boolean},
+  ): Keypair {
+    const keypair = nacl.sign.keyPair.fromSecretKey(secretKey);
+    if (!options || !options.skipValidation) {
+      const encoder = new TextEncoder();
+      const signData = encoder.encode('@solana/web3.js-validation-v1');
+      const signature = nacl.sign.detached(signData, keypair.secretKey);
+      if (!nacl.sign.detached.verify(signData, signature, keypair.publicKey)) {
+        throw new Error('provided secretKey is invalid');
+      }
+    }
+    return new Keypair(keypair);
+  }
+
+  /**
+   * Generate a keypair from a 32 byte seed.
+   *
+   * @param seed seed byte array
+   */
+  static fromSeed(seed: Uint8Array): Keypair {
+    return new Keypair(nacl.sign.keyPair.fromSeed(seed));
+  }
+
+  /**
+   * The public key for this keypair
+   */
+  get publicKey(): PublicKey {
+    return new PublicKey(this.keypair.publicKey);
+  }
+
+  /**
+   * The raw secret key for this keypair
+   */
+  get secretKey(): Uint8Array {
+    return this.keypair.secretKey;
+  }
+}