/**
 * Encrypt src with Salsa20/20 stream generated for the given 32-byte key
 * and 8-byte and write the result into dst and return it.
 *
 * dst and src may be the same, but otherwise must not overlap.
 *
 * Never use the same key and nonce to encrypt more than one message.
 *
 * If nonceInplaceCounterLength is not 0, the nonce is assumed to be a 16-byte
 * array with stream counter in first nonceInplaceCounterLength bytes and nonce
 * in the last remaining bytes. The counter will be incremented inplace for
 * each Salsa20 block. This is useful if you need to encrypt one stream of data
 * in chunks.
 */
export declare function streamXOR(key: Uint8Array, nonce: Uint8Array, src: Uint8Array, dst: Uint8Array, nonceInplaceCounterLength?: number): Uint8Array;
/**
 * Generate Salsa20/20 stream for the given 32-byte key and 8-byte nonce
 * and write it into dst and return it.
 *
 * Never use the same key and nonce to generate more than one stream.
 *
 * If nonceInplaceCounterLength is not 0, it behaves the same
 * with respect to the nonce as described in streamXOR documentation.
 *
 * stream is like streamXOR with all-zero src.
 */
export declare function stream(key: Uint8Array, nonce: Uint8Array, dst: Uint8Array, nonceInplaceCounterLength?: number): Uint8Array;