/**
 * Decoded form of a c2sp.org/tlog-checkpoint body. The body shape is
 * hash-and-algo-agnostic: `rootHash` is 32 bytes for both the SHA-256 and
 * BLAKE3 trees Phase 7 ships, but the codec only enforces a caller-supplied
 * length in `parseCheckpointBody`. The signed-note envelope that wraps a
 * checkpoint is handled in `signed-note.ts`.
 */
export interface Checkpoint {
    /**
     * Log identity, non-empty UTF-8 with no Unicode spaces, plus signs, or
     * embedded newlines. Per c2sp.org/tlog-checkpoint §Note text the origin
     * SHOULD be a schemeless URL such as `example.com/log42`, but the codec
     * only enforces the MUST-level structural constraints; broader URL
     * shape policy is a caller concern.
     */
    readonly origin: string;
    /**
     * Number of leaves in the tree at signing time. Must be a non-negative
     * safe integer; ASCII decimal serialization carries no leading zeroes
     * (the literal `0` is the only valid string starting with `0`).
     */
    readonly treeSize: number;
    /**
     * Merkle root hash. 32 bytes for both Sha256Tree and Blake3Tree; the
     * caller-supplied `expectedHashLen` parameter on `parseCheckpointBody`
     * pins the exact length for a given hasher.
     */
    readonly rootHash: Uint8Array;
}
/**
 * Serialize a Checkpoint into its canonical body bytes per
 * c2sp.org/tlog-checkpoint §Note text. Layout:
 *
 *     utf8(origin) || 0x0A || utf8(decimal(treeSize)) || 0x0A
 *         || base64(rootHash) || 0x0A
 *
 * Base64 uses the RFC 4648 §4 standard alphabet with `=` padding (NOT the
 * URL-safe variant from §5 and NOT padding-stripped). The body has no
 * leading or trailing whitespace beyond the final 0x0A; byte stability
 * is the entire purpose of the codec, since the body bytes are what the
 * STH signature is computed over.
 */
export declare function serializeCheckpointBody(c: Checkpoint): Uint8Array;
/**
 * Parse a canonical checkpoint body. Inverse of `serializeCheckpointBody`;
 * round-trips byte-for-byte. Rejects extension lines, leading or trailing
 * whitespace beyond the mandatory final 0x0A, non-newline ASCII control
 * characters, malformed base64, and root hashes whose decoded length does
 * not match `expectedHashLen` (default 32, the size for both Sha256Tree
 * and Blake3Tree).
 *
 * The caller pins `expectedHashLen` to its hasher's `outputSize`; a future
 * SignedLog (TASK-4) will bind this to the tree's hasher automatically.
 *
 * Per c2sp.org/tlog-checkpoint §Note text and c2sp.org/signed-note
 * §Format.
 */
export declare function parseCheckpointBody(bytes: Uint8Array, expectedHashLen?: number): Checkpoint;