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# Random Number Generation
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Cryptographically secure random number generation in various formats for keys, nonces, and other security-critical randomness.
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## Capabilities
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### Random Bytes
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Generate cryptographically secure random bytes.
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```typescript { .api }
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/**
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 * Generate random bytes
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 * @param bitLength - Length in bits (default: 256)
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 * @returns Random bytes as Uint8Array
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 */
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function randomAsU8a(bitLength?: number): Uint8Array;
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/**
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 * Generate random hex string
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 * @param bitLength - Length in bits (default: 256)
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 * @returns Random hex string with 0x prefix
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 */
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function randomAsHex(bitLength?: number): string;
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/**
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 * Generate random number
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 * @param bitLength - Length in bits (default: 53)
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 * @returns Random number within JavaScript safe integer range
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 */
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function randomAsNumber(bitLength?: number): number;
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```
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**Usage Examples:**
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```typescript
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import { randomAsU8a, randomAsHex, randomAsNumber } from "@polkadot/util-crypto";
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// Generate 32 random bytes (256 bits)
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const randomBytes = randomAsU8a(256);
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console.log(randomBytes.length); // 32
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// Generate random hex string
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const randomHex = randomAsHex(128); // 16 bytes as hex
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console.log(randomHex); // "0x..."
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// Generate random number (up to 53 bits for JavaScript safety)
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const randomNum = randomAsNumber(32);
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console.log(randomNum); // Random 32-bit integer
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```