age-encryption/dist/stream.js

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import { chacha20poly1305 } from "@noble/ciphers/chacha";
const chacha20poly1305Overhead = 16;
const chunkSize = /* @__PURE__ */ (() => 64 * 1024)();
const chunkSizeWithOverhead = /* @__PURE__ */ (() => chunkSize + chacha20poly1305Overhead)();
export function decryptSTREAM(key) {
    const streamNonce = new Uint8Array(12);
    const incNonce = () => {
        for (let i = streamNonce.length - 2; i >= 0; i--) {
            streamNonce[i]++;
            if (streamNonce[i] !== 0)
                break;
        }
    };
    let firstChunk = true;
    const ciphertextBuffer = new Uint8Array(chunkSizeWithOverhead);
    let ciphertextBufferUsed = 0;
    return new TransformStream({
        transform(chunk, controller) {
            while (chunk.length > 0) {
                if (ciphertextBufferUsed === ciphertextBuffer.length) {
                    const decryptedChunk = chacha20poly1305(key, streamNonce)
                        .decrypt(ciphertextBuffer);
                    controller.enqueue(decryptedChunk);
                    incNonce();
                    ciphertextBufferUsed = 0;
                    firstChunk = false;
                }
                const n = Math.min(ciphertextBuffer.length - ciphertextBufferUsed, chunk.length);
                ciphertextBuffer.set(chunk.subarray(0, n), ciphertextBufferUsed);
                ciphertextBufferUsed += n;
                chunk = chunk.subarray(n);
            }
        },
        flush(controller) {
            streamNonce[11] = 1; // Last chunk flag.
            const decryptedChunk = chacha20poly1305(key, streamNonce)
                .decrypt(ciphertextBuffer.subarray(0, ciphertextBufferUsed));
            if (!firstChunk && decryptedChunk.length === 0) {
                // The final chunk can only be empty if it's the first one.
                throw new Error("final chunk is empty");
            }
            controller.enqueue(decryptedChunk);
        },
    });
}
export function plaintextSize(ciphertextSize) {
    if (ciphertextSize < chacha20poly1305Overhead) {
        throw Error("ciphertext is too small");
    }
    if (ciphertextSize === chacha20poly1305Overhead) {
        return 0; // Empty plaintext.
    }
    const fullChunks = Math.floor(ciphertextSize / chunkSizeWithOverhead);
    const lastChunk = ciphertextSize % chunkSizeWithOverhead;
    if (0 < lastChunk && lastChunk <= chacha20poly1305Overhead) {
        throw Error("ciphertext size is invalid");
    }
    let size = ciphertextSize;
    size -= fullChunks * chacha20poly1305Overhead;
    size -= lastChunk > 0 ? chacha20poly1305Overhead : 0;
    return size;
}
export function encryptSTREAM(key) {
    const streamNonce = new Uint8Array(12);
    const incNonce = () => {
        for (let i = streamNonce.length - 2; i >= 0; i--) {
            streamNonce[i]++;
            if (streamNonce[i] !== 0)
                break;
        }
    };
    const plaintextBuffer = new Uint8Array(chunkSize);
    let plaintextBufferUsed = 0;
    return new TransformStream({
        transform(chunk, controller) {
            while (chunk.length > 0) {
                if (plaintextBufferUsed === plaintextBuffer.length) {
                    const encryptedChunk = chacha20poly1305(key, streamNonce)
                        .encrypt(plaintextBuffer);
                    controller.enqueue(encryptedChunk);
                    incNonce();
                    plaintextBufferUsed = 0;
                }
                const n = Math.min(plaintextBuffer.length - plaintextBufferUsed, chunk.length);
                plaintextBuffer.set(chunk.subarray(0, n), plaintextBufferUsed);
                plaintextBufferUsed += n;
                chunk = chunk.subarray(n);
            }
        },
        flush(controller) {
            streamNonce[11] = 1; // Last chunk flag.
            const encryptedChunk = chacha20poly1305(key, streamNonce)
                .encrypt(plaintextBuffer.subarray(0, plaintextBufferUsed));
            controller.enqueue(encryptedChunk);
        },
    });
}
export function ciphertextSize(plaintextSize) {
    const chunks = Math.max(1, Math.ceil(plaintextSize / chunkSize));
    return plaintextSize + chacha20poly1305Overhead * chunks;
}