diff --git a/.gitignore b/.gitignore
index 0d4abbcd..805fe8d3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,6 +2,7 @@
 node_modules/
 npm*
 test/lib/
+test/typescript/definitions.js
 dist/
 openpgp.store/
 .nyc_output/
diff --git a/.travis.yml b/.travis.yml
index 7aa90100..db373d49 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,6 +7,8 @@ matrix:
   include:
     - node_js: "14"
       env: OPENPGP_NODE_JS='14' OPENPGPJSTEST='lint'
+    - node_js: "14"
+      env: OPENPGP_NODE_JS='14' OPENPGPJSTEST='test-type-definitions'
     - node_js: "10"
       env: OPENPGP_NODE_JS='10' OPENPGPJSTEST='unit'
     - node_js: "12"
diff --git a/lightweight/package.json b/lightweight/package.json
index 779adefe..134e03c9 100644
--- a/lightweight/package.json
+++ b/lightweight/package.json
@@ -1,4 +1,5 @@
 {
   "name": "openpgp-lightweight",
-  "main": "../dist/lightweight/openpgp.min.mjs"
+  "main": "../dist/lightweight/openpgp.min.mjs",
+  "types": "../openpgp.d.ts"
 }
diff --git a/openpgp.d.ts b/openpgp.d.ts
new file mode 100644
index 00000000..c1b182ce
--- /dev/null
+++ b/openpgp.d.ts
@@ -0,0 +1,895 @@
+/**
+ * Type definitions for OpenPGP.js http://openpgpjs.org/
+ * 
+ * Contributors:
+ *  - FlowCrypt a. s. <https://flowcrypt.com>
+ *  - Guillaume Lacasa <https://blog.lacasa.fr>
+ *  - Errietta Kostala <https://github.com/errietta>
+ */
+
+/* ############## v5 KEY #################### */
+
+export function readArmoredKey(armoredText: string): Promise<Key>;
+export function readKey(data: Uint8Array): Promise<Key>;
+export function readArmoredKeys(armoredText: string): Promise<Key[]>;
+export function readKeys(data: Uint8Array): Promise<Key[]>;
+export function generateKey(options: KeyOptions): Promise<KeyPair>;
+export function generateSessionKey(options: { publicKeys: Key[], date?: Date, toUserIds?: UserId[] }): Promise<SessionKey>;
+export function decryptKey(options: { privateKey: Key; passphrase?: string | string[]; }): Promise<Key>;
+export function encryptKey(options: { privateKey: Key; passphrase?: string }): Promise<Key>;
+export function reformatKey(options: { privateKey: Key; userIds?: (string | UserId)[]; passphrase?: string; keyExpirationTime?: number; }): Promise<KeyPair>;
+
+export class Key {
+  public primaryKey: PublicKeyPacket | SecretKeyPacket;
+  public subKeys: SubKey[];
+  public users: User[];
+  public revocationSignatures: SignaturePacket[];
+  public keyPacket: PublicKeyPacket | SecretKeyPacket;
+  constructor(packetlist: PacketList<AnyPacket>);
+  public armor(): string;
+  public decrypt(passphrase: string | string[], keyId?: Keyid): Promise<boolean>;
+  public encrypt(passphrase: string | string[]): Promise<void>;
+  public getExpirationTime(capability?: 'encrypt' | 'encrypt_sign' | 'sign' | null, keyId?: Keyid | null, userId?: UserId | null): Promise<Date | typeof Infinity | null>; // Returns null if `capabilities` is passed and the key does not have the specified capabilities or is revoked or invalid.
+  public getKeyIds(): Keyid[];
+  public getPrimaryUser(): Promise<PrimaryUser>; // throws on err
+  public getUserIds(): string[];
+  public isPrivate(): boolean;
+  public isPublic(): boolean;
+  public toPublic(): Key;
+  public update(key: Key): void;
+  public verifyPrimaryKey(): Promise<void>; // throws on err
+  public isRevoked(): Promise<boolean>;
+  public revoke(reason: { flag?: enums.reasonForRevocation; string?: string; }, date?: Date): Promise<Key>;
+  public getRevocationCertificate(): Promise<Stream<string> | string | undefined>;
+  public getEncryptionKey(keyid?: Keyid | null, date?: Date, userId?: UserId | null): Promise<Key | SubKey | null>;
+  public getSigningKey(keyid?: Keyid | null, date?: Date, userId?: UserId | null): Promise<Key | SubKey | null>;
+  public getKeys(keyId?: Keyid): (Key | SubKey)[];
+  public isDecrypted(): boolean;
+  public getFingerprint(): string;
+  public getCreationTime(): Date;
+  public getAlgorithmInfo(): AlgorithmInfo;
+  public getKeyId(): Keyid;
+}
+
+export class SubKey {
+  public subKey: SecretSubkeyPacket | PublicSubkeyPacket;
+  public keyPacket: SecretKeyPacket;
+  public bindingSignatures: SignaturePacket[];
+  public revocationSignatures: SignaturePacket[];
+  constructor(subKeyPacket: SecretSubkeyPacket | PublicSubkeyPacket);
+  public verify(primaryKey: PublicKeyPacket | SecretKeyPacket): Promise<enums.keyStatus>;
+  public isDecrypted(): boolean;
+  public getFingerprint(): string;
+  public getCreationTime(): Date;
+  public getAlgorithmInfo(): AlgorithmInfo;
+  public getKeyId(): Keyid;
+}
+
+export interface User {
+  userId: UserIDPacket | null;
+  userAttribute: UserAttributePacket | null;
+  selfCertifications: SignaturePacket[];
+  otherCertifications: SignaturePacket[];
+  revocationSignatures: SignaturePacket[];
+}
+
+export interface PrimaryUser {
+  index: number;
+  user: User;
+}
+
+type AlgorithmInfo = {
+  algorithm: enums.publicKeyNames;
+  bits: number;
+};
+
+/* ############## v5 SIG #################### */
+
+export function readArmoredSignature(armoredText: string): Promise<Signature>;
+export function readSignature(input: Uint8Array): Promise<Signature>;
+
+export class Signature {
+  public packets: PacketList<SignaturePacket>;
+  constructor(packetlist: PacketList<SignaturePacket>);
+  public armor(): string;
+}
+
+export interface VerificationResult {
+  keyid: Keyid;
+  verified: Promise<null | boolean>;
+  signature: Promise<Signature>;
+}
+
+/* ############## v5 CLEARTEXT #################### */
+
+export function readArmoredCleartextMessage(armoredText: string): Promise<CleartextMessage>;
+
+/** Class that represents an OpenPGP cleartext signed message.
+ */
+export class CleartextMessage {
+  /** Returns ASCII armored text of cleartext signed message
+   */
+  armor(): string;
+
+  /** Returns the key IDs of the keys that signed the cleartext message
+   */
+  getSigningKeyIds(): Array<Keyid>;
+
+  /** Get cleartext
+   */
+  getText(): string;
+
+  /** Sign the cleartext message
+   *
+   *  @param privateKeys private keys with decrypted secret key data for signing
+   */
+  sign(privateKeys: Array<Key>): void;
+
+  /** Verify signatures of cleartext signed message
+   *  @param keys array of keys to verify signatures
+   */
+  verify(keys: Key[], date?: Date, streaming?: boolean): Promise<VerificationResult[]>;
+
+  static fromText(text: string): CleartextMessage;
+}
+
+/* ############## v5 MSG #################### */
+
+export function readArmoredMessage<T extends MaybeStream<string>>(armoredText: T): Promise<Message<T>>;
+export function readMessage<T extends MaybeStream<Uint8Array>>(input: T): Promise<Message<T>>;
+
+export function encrypt<T extends 'web' | 'node' | false>(options: EncryptOptions & { streaming: T, armor: false }): Promise<
+  T extends 'web' ? WebStream<Uint8Array> :
+  T extends 'node' ? NodeStream<Uint8Array> :
+  Uint8Array
+>;
+export function encrypt<T extends 'web' | 'node' | false>(options: EncryptOptions & { streaming: T }): Promise<
+  T extends 'web' ? WebStream<string> :
+  T extends 'node' ? NodeStream<string> :
+  string
+>;
+export function encrypt<T extends MaybeStream<Data>>(options: EncryptOptions & { message: Message<T>, armor: false }): Promise<
+  T extends WebStream<infer X> ? WebStream<Uint8Array> :
+  T extends NodeStream<infer X> ? NodeStream<Uint8Array> :
+  Uint8Array
+>;
+export function encrypt<T extends MaybeStream<Data>>(options: EncryptOptions & { message: Message<T> }): Promise<
+  T extends WebStream<infer X> ? WebStream<string> :
+  T extends NodeStream<infer X> ? NodeStream<string> :
+  string
+>;
+
+export function sign<T extends 'web' | 'node' | false>(options: SignOptions & { streaming: T, armor: false }): Promise<
+  T extends 'web' ? WebStream<Uint8Array> :
+  T extends 'node' ? NodeStream<Uint8Array> :
+  Uint8Array
+>;
+export function sign<T extends 'web' | 'node' | false>(options: SignOptions & { streaming: T }): Promise<
+  T extends 'web' ? WebStream<string> :
+  T extends 'node' ? NodeStream<string> :
+  string
+>;
+export function sign<T extends MaybeStream<Data>>(options: SignOptions & { message: Message<T>, armor: false }): Promise<
+  T extends WebStream<infer X> ? WebStream<Uint8Array> :
+  T extends NodeStream<infer X> ? NodeStream<Uint8Array> :
+  Uint8Array
+>;
+export function sign<T extends MaybeStream<Data>>(options: SignOptions & { message: Message<T> }): Promise<
+  T extends WebStream<infer X> ? WebStream<string> :
+  T extends NodeStream<infer X> ? NodeStream<string> :
+  string
+>;
+export function sign(options: SignOptions & { message: CleartextMessage }): Promise<string>;
+
+export function decrypt<T extends 'web' | 'node' | false>(options: DecryptOptions & { streaming: T, format: 'binary' }): Promise<DecryptMessageResult & {
+  data:
+  T extends 'web' ? WebStream<Uint8Array> :
+  T extends 'node' ? NodeStream<Uint8Array> :
+  Uint8Array
+}>;
+export function decrypt<T extends 'web' | 'node' | false>(options: DecryptOptions & { streaming: T }): Promise<DecryptMessageResult & {
+  data:
+  T extends 'web' ? WebStream<string> :
+  T extends 'node' ? NodeStream<string> :
+  string
+}>;
+export function decrypt<T extends MaybeStream<Data>>(options: DecryptOptions & { message: Message<T>, format: 'binary' }): Promise<DecryptMessageResult & {
+  data:
+  T extends WebStream<infer X> ? WebStream<Uint8Array> :
+  T extends NodeStream<infer X> ? NodeStream<Uint8Array> :
+  Uint8Array
+}>;
+export function decrypt<T extends MaybeStream<Data>>(options: DecryptOptions & { message: Message<T> }): Promise<DecryptMessageResult & {
+  data:
+  T extends WebStream<infer X> ? WebStream<string> :
+  T extends NodeStream<infer X> ? NodeStream<string> :
+  string
+}>;
+
+export function verify<T extends 'web' | 'node' | false>(options: VerifyOptions & { streaming: T, format: 'binary' }): Promise<VerifyMessageResult & {
+  data:
+  T extends 'web' ? WebStream<Uint8Array> :
+  T extends 'node' ? NodeStream<Uint8Array> :
+  Uint8Array
+}>;
+export function verify<T extends 'web' | 'node' | false>(options: VerifyOptions & { streaming: T }): Promise<VerifyMessageResult & {
+  data:
+  T extends 'web' ? WebStream<string> :
+  T extends 'node' ? NodeStream<string> :
+  string
+}>;
+export function verify<T extends MaybeStream<Data>>(options: VerifyOptions & { message: Message<T>, format: 'binary' }): Promise<VerifyMessageResult & {
+  data:
+  T extends WebStream<infer X> ? WebStream<Uint8Array> :
+  T extends NodeStream<infer X> ? NodeStream<Uint8Array> :
+  Uint8Array
+}>;
+export function verify<T extends MaybeStream<Data>>(options: VerifyOptions & { message: Message<T> }): Promise<VerifyMessageResult & {
+  data:
+  T extends WebStream<infer X> ? WebStream<string> :
+  T extends NodeStream<infer X> ? NodeStream<string> :
+  string
+}>;
+
+/** Class that represents an OpenPGP message.  Can be an encrypted message, signed message, compressed message or literal message
+ */
+export class Message<T extends MaybeStream<Data>> {
+
+  public packets: PacketList<AnyPacket>;
+  constructor(packetlist: PacketList<AnyPacket>);
+
+  /** Returns ASCII armored text of message
+   */
+  public armor(): string;
+
+  /** Decrypt the message
+      @param privateKey private key with decrypted secret data
+  */
+  public decrypt(privateKeys?: Key[] | null, passwords?: string[] | null, sessionKeys?: SessionKey[] | null, streaming?: boolean): Promise<Message<MaybeStream<Data>>>;
+
+  /** Encrypt the message
+      @param keys array of keys, used to encrypt the message
+  */
+  public encrypt(keys: Key[]): Promise<Message<MaybeStream<Data>>>;
+
+  /** Returns the key IDs of the keys to which the session key is encrypted
+   */
+  public getEncryptionKeyIds(): Keyid[];
+
+  /** Get literal data that is the body of the message
+   */
+  public getLiteralData(): Uint8Array | null | Stream<Uint8Array>;
+
+  /** Returns the key IDs of the keys that signed the message
+   */
+  public getSigningKeyIds(): Keyid[];
+
+  /** Get literal data as text
+   */
+  public getText(): string | null | Stream<string>;
+
+  public getFilename(): string | null;
+
+  /** Sign the message (the literal data packet of the message)
+      @param privateKey private keys with decrypted secret key data for signing
+  */
+  public sign(privateKey: Key[]): Promise<Message<T>>;
+
+  /** Unwrap compressed message
+   */
+  public unwrapCompressed(): Message<T>;
+
+  /** Verify message signatures
+      @param keys array of keys to verify signatures
+  */
+  public verify(keys: Key[], date?: Date, streaming?: boolean): Promise<VerificationResult[]>;
+
+  /**
+   * Append signature to unencrypted message object
+   * @param {String|Uint8Array} detachedSignature The detached ASCII-armored or Uint8Array PGP signature
+   */
+  public appendSignature(detachedSignature: string | Uint8Array): Promise<void>;
+
+  static fromText<T extends MaybeStream<string>>(text: T, filename?: string, date?: Date, type?: DataPacketType): Message<T>;
+  static fromBinary<T extends MaybeStream<Uint8Array>>(bytes: T, filename?: string, date?: Date, type?: DataPacketType): Message<T>;
+}
+
+
+/* ############## v5 CONFIG #################### */
+
+export namespace config {
+  let preferHashAlgorithm: enums.hash;
+  let encryptionCipher: enums.symmetric;
+  let compression: enums.compression;
+  let showVersion: boolean;
+  let showComment: boolean;
+  let integrityProtect: boolean;
+  let debug: boolean;
+  let deflateLevel: number;
+  let aeadProtect: boolean;
+  let ignoreMdcError: boolean;
+  let checksumRequired: boolean;
+  let rsaBlinding: boolean;
+  let passwordCollisionCheck: boolean;
+  let revocationsExpire: boolean;
+  let useNative: boolean;
+  let zeroCopy: boolean;
+  let tolerant: boolean;
+  let versionString: string;
+  let commentString: string;
+  let keyserver: string;
+  let nodeStore: string;
+  let allowInsecureDecryptionWithSigningKeys: boolean;
+}
+
+/* ############## v5 PACKET #################### */
+
+declare class BasePacket {
+  public tag: enums.packet;
+  public read(bytes: Uint8Array): void;
+  public write(): Uint8Array;
+}
+
+declare class BaseKeyPacket extends BasePacket {
+  // fingerprint: Uint8Array|null; - not included because not recommended to use. Use getFingerprint() or getFingerprintBytes()
+  public algorithm: enums.publicKey;
+  public created: Date;
+
+  public version: number;
+  public expirationTimeV3: number | null;
+  public keyExpirationTime: number | null;
+  public getBitSize(): number;
+  public getAlgorithmInfo(): AlgorithmInfo;
+  public getFingerprint(): string;
+  public getFingerprintBytes(): Uint8Array | null;
+  public getCreationTime(): Date;
+  public getKeyId(): Keyid;
+  public params: object[];
+  public isDecrypted(): boolean;
+  public isEncrypted: boolean; // may be null, false or true
+}
+
+declare class BasePrimaryKeyPacket extends BaseKeyPacket {
+}
+
+export class CompressedDataPacket extends BasePacket {
+  public tag: enums.packet.compressedData;
+}
+
+export class SymEncryptedIntegrityProtectedDataPacket extends BasePacket {
+  public tag: enums.packet.symEncryptedIntegrityProtectedData;
+}
+
+export class AEADEncryptedDataPacket extends BasePacket {
+  public tag: enums.packet.AEADEncryptedData;
+}
+
+export class PublicKeyEncryptedSessionKeyPaclet extends BasePacket {
+  public tag: enums.packet.publicKeyEncryptedSessionKey;
+}
+
+export class SymEncryptedSessionKey extends BasePacket {
+  public tag: enums.packet.symEncryptedSessionKey;
+}
+
+export class LiteralDataPacket extends BasePacket {
+  public tag: enums.packet.literalData;
+}
+
+export class PublicKeyPacket extends BasePrimaryKeyPacket {
+  public tag: enums.packet.publicKey;
+}
+
+export class SymmetricallyEncryptedDataPacket extends BasePacket {
+  public tag: enums.packet.symmetricallyEncryptedData;
+}
+
+export class MarkerPacket extends BasePacket {
+  public tag: enums.packet.marker;
+}
+
+export class PublicSubkeyPacket extends BaseKeyPacket {
+  public tag: enums.packet.publicSubkey;
+}
+
+export class UserAttributePacket extends BasePacket {
+  public tag: enums.packet.userAttribute;
+}
+
+export class OnePassSignaturePacket extends BasePacket {
+  public tag: enums.packet.onePassSignature;
+  public correspondingSig?: Promise<SignaturePacket>;
+}
+
+export class SecretKeyPacket extends BasePrimaryKeyPacket {
+  public tag: enums.packet.secretKey;
+  // encrypted: null | unknown[]; // Encrypted secret-key data, not meant for public use
+  public s2k: { type: string } | null;
+  public encrypt(passphrase: string): Promise<boolean>;
+  public decrypt(passphrase: string): Promise<true>;
+}
+
+export class UserIDPacket extends BasePacket {
+  public tag: enums.packet.userID;
+  public userid: string;
+}
+
+export class SecretSubkeyPacket extends BaseKeyPacket {
+  public tag: enums.packet.secretSubkey;
+  // encrypted: null | unknown[]; // Encrypted secret-key data, not meant for public use
+  public s2k: { type: string } | null;
+  public encrypt(passphrase: string): Promise<boolean>;
+  public decrypt(passphrase: string): Promise<true>;
+}
+
+export class SignaturePacket extends BasePacket {
+  public tag: enums.packet.signature;
+  public version: number;
+  public signatureType: null | number;
+  public hashAlgorithm: null | number;
+  public publicKeyAlgorithm: null | number;
+  public signatureData: null | Uint8Array;
+  public unhashedSubpackets: null | Uint8Array;
+  public signedHashValue: null | Uint8Array;
+  public created: Date;
+  public signatureExpirationTime: null | number;
+  public signatureNeverExpires: boolean;
+  public exportable: null | boolean;
+  public trustLevel: null | number;
+  public trustAmount: null | number;
+  public regularExpression: null | number;
+  public revocable: null | boolean;
+  public keyExpirationTime: null | number;
+  public keyNeverExpires: null | boolean;
+  public preferredSymmetricAlgorithms: null | number[];
+  public revocationKeyClass: null | number;
+  public revocationKeyAlgorithm: null | number;
+  public revocationKeyFingerprint: null | Uint8Array;
+  public issuerKeyId: Keyid;
+  public notation: null | { [name: string]: string };
+  public preferredHashAlgorithms: null | number[];
+  public preferredCompressionAlgorithms: null | number[];
+  public keyServerPreferences: null | number[];
+  public preferredKeyServer: null | string;
+  public isPrimaryUserID: null | boolean;
+  public policyURI: null | string;
+  public keyFlags: null | number[];
+  public signersUserId: null | string;
+  public reasonForRevocationFlag: null | number;
+  public reasonForRevocationString: null | string;
+  public features: null | number[];
+  public signatureTargetPublicKeyAlgorithm: null | number;
+  public signatureTargetHashAlgorithm: null | number;
+  public signatureTargetHash: null | string;
+  public embeddedSignature: null | SignaturePacket;
+  public issuerKeyVersion: null | number;
+  public issuerFingerprint: null | Uint8Array;
+  public preferredAeadAlgorithms: null | Uint8Array;
+  public verified: null | boolean;
+  public revoked: null | boolean;
+  public sign(key: SecretKeyPacket | SecretSubkeyPacket, data: Uint8Array): true;
+  public isExpired(date?: Date): boolean;
+  public getExpirationTime(): Date | typeof Infinity;
+}
+
+export class TrustPacket extends BasePacket {
+  public tag: enums.packet.trust;
+}
+
+export type AnyPacket = CompressedDataPacket | SymEncryptedIntegrityProtectedDataPacket | AEADEncryptedDataPacket | PublicKeyEncryptedSessionKeyPaclet | SymEncryptedSessionKey | LiteralDataPacket
+  | PublicKeyPacket | SymmetricallyEncryptedDataPacket | MarkerPacket | PublicSubkeyPacket | UserAttributePacket | OnePassSignaturePacket | SecretKeyPacket | UserIDPacket | SecretSubkeyPacket | SignaturePacket | TrustPacket;
+export type AnySecretPacket = SecretKeyPacket | SecretSubkeyPacket;
+export type AnyKeyPacket = PublicKeyPacket | SecretKeyPacket | PublicSubkeyPacket | SecretSubkeyPacket;
+
+type DataPacketType = 'utf8' | 'binary' | 'text' | 'mime';
+
+
+export class PacketList<PACKET_TYPE> extends Array<PACKET_TYPE> {
+  [index: number]: PACKET_TYPE;
+  public length: number;
+  public read(bytes: Uint8Array): void;
+  public write(): Uint8Array;
+  public push(...packet: PACKET_TYPE[]): number;
+  public pop(): PACKET_TYPE;
+  public filter(callback: (packet: PACKET_TYPE, i: number, self: PacketList<PACKET_TYPE>) => void): PacketList<PACKET_TYPE>;
+  public filterByTag(...args: enums.packet[]): PacketList<PACKET_TYPE>;
+  public forEach(callback: (packet: PACKET_TYPE, i: number, self: PacketList<PACKET_TYPE>) => void): void;
+  public map<RETURN_TYPE>(callback: (packet: PACKET_TYPE, i: number, self: PacketList<PACKET_TYPE>) => RETURN_TYPE): PacketList<RETURN_TYPE>;
+  // some()
+  // every()
+  // findPacket()
+  // indexOfTag()
+  // slice()
+  // concat()
+  // fromStructuredClone()
+}
+
+/* ############## v5 STREAM #################### */
+
+type Data = Uint8Array | string;
+interface BaseStream<T extends Data> { }
+interface WebStream<T extends Data> extends BaseStream<T> { // copied+simplified version of ReadableStream from lib.dom.d.ts
+  readonly locked: boolean; getReader: Function; pipeThrough: Function; pipeTo: Function; tee: Function;
+  cancel(reason?: any): Promise<void>;
+}
+interface NodeStream<T extends Data> extends BaseStream<T> { // copied+simplified version of ReadableStream from @types/node/index.d.ts
+  readable: boolean; pipe: Function; unpipe: Function; wrap: Function;
+  read(size?: number): string | Uint8Array; setEncoding(encoding: string): this; pause(): this; resume(): this;
+  isPaused(): boolean; unshift(chunk: string | Uint8Array): void;
+}
+type Stream<T extends Data> = WebStream<T> | NodeStream<T>;
+type MaybeStream<T extends Data> = T | Stream<T>;
+
+export namespace stream {
+  function readToEnd<T extends Data>(input: MaybeStream<T>, concat?: (list: T[]) => T): Promise<T>;
+  // concat
+  // slice
+  // clone
+  // webToNode
+  // nodeToWeb
+}
+
+/* ############## v5 GENERAL #################### */
+
+export interface UserId { name?: string; email?: string; }
+export interface SessionKey { data: Uint8Array; algorithm: string; }
+
+
+interface EncryptOptions {
+  /** message to be encrypted as created by Message.fromText or Message.fromBinary */
+  message: Message<MaybeStream<Data>>;
+  /** (optional) array of keys or single key, used to encrypt the message */
+  publicKeys?: Key | Key[];
+  /** (optional) private keys for signing. If omitted message will not be signed */
+  privateKeys?: Key | Key[];
+  /** (optional) array of passwords or a single password to encrypt the message */
+  passwords?: string | string[];
+  /** (optional) session key in the form: { data:Uint8Array, algorithm:String } */
+  sessionKey?: SessionKey;
+  /** (optional) which compression algorithm to compress the message with, defaults to what is specified in config */
+  compression?: enums.compression;
+  /** if the return values should be ascii armored or the message/signature objects */
+  armor?: boolean;
+  /** (optional) whether to return data as a stream. Defaults to the type of stream `message` was created from, if any. */
+  streaming?: 'web' | 'node' | false;
+  /** (optional) if the signature should be detached (if true, signature will be added to returned object) */
+  signature?: Signature;
+  /** (optional) encrypt as of a certain date */
+  date?: Date;
+  /** (optional) use a key ID of 0 instead of the public key IDs */
+  wildcard?: boolean;
+  /** (optional) user ID to sign with, e.g. { name:'Steve Sender', email:'steve@openpgp.org' } */
+  fromUserId?: UserId;
+  /** (optional) user ID to encrypt for, e.g. { name:'Robert Receiver', email:'robert@openpgp.org' } */
+  toUserId?: UserId;
+}
+
+export interface DecryptOptions {
+  /** the message object with the encrypted data */
+  message: Message<MaybeStream<Data>>;
+  /** (optional) private keys with decrypted secret key data or session key */
+  privateKeys?: Key | Key[];
+  /** (optional) passwords to decrypt the message */
+  passwords?: string | string[];
+  /** (optional) session keys in the form: { data:Uint8Array, algorithm:String } */
+  sessionKeys?: SessionKey | SessionKey[];
+  /** (optional) array of public keys or single key, to verify signatures */
+  publicKeys?: Key | Key[];
+  /** (optional) whether to return data as a string(Stream) or Uint8Array(Stream). If 'utf8' (the default), also normalize newlines. */
+  format?: 'utf8' | 'binary';
+  /** (optional) whether to return data as a stream. Defaults to the type of stream `message` was created from, if any. */
+  streaming?: 'web' | 'node' | false;
+  /** (optional) detached signature for verification */
+  signature?: Signature;
+  /** (optional) use the given date for verification instead of the current time */
+  date?: Date;
+}
+
+export interface SignOptions {
+  message: CleartextMessage | Message<MaybeStream<Data>>;
+  privateKeys?: Key | Key[];
+  armor?: boolean;
+  streaming?: 'web' | 'node' | false;
+  dataType?: DataPacketType;
+  detached?: boolean;
+  date?: Date;
+  fromUserId?: UserId;
+}
+
+export interface VerifyOptions {
+  /** array of publicKeys or single key, to verify signatures */
+  publicKeys: Key | Key[];
+  /** (cleartext) message object with signatures */
+  message: CleartextMessage | Message<MaybeStream<Data>>;
+  /** (optional) whether to return data as a string(Stream) or Uint8Array(Stream). If 'utf8' (the default), also normalize newlines. */
+  format?: 'utf8' | 'binary';
+  /** (optional) whether to return data as a stream. Defaults to the type of stream `message` was created from, if any. */
+  streaming?: 'web' | 'node' | false;
+  /** (optional) detached signature for verification */
+  signature?: Signature;
+  /** (optional) use the given date for verification instead of the current time */
+  date?: Date;
+}
+
+export interface KeyPair {
+  key: Key;
+  privateKeyArmored: string;
+  publicKeyArmored: string;
+}
+
+export type EllipticCurveName = 'curve25519' | 'p256' | 'p384' | 'p521' | 'secp256k1' | 'brainpoolP256r1' | 'brainpoolP384r1' | 'brainpoolP512r1';
+
+export interface KeyOptions {
+  userIds: UserId[]; // generating a key with no user defined results in error
+  passphrase?: string;
+  numBits?: number;
+  keyExpirationTime?: number;
+  curve?: EllipticCurveName;
+  date?: Date;
+  subkeys?: KeyOptions[];
+}
+
+/**
+ * Intended for internal use with openpgp.generate()
+ * It's recommended that users choose openpgp.generateKey() that requires KeyOptions instead
+ */
+export interface FullKeyOptions {
+  userIds: UserId[];
+  passphrase?: string;
+  numBits?: number;
+  keyExpirationTime?: number;
+  curve?: EllipticCurveName;
+  date?: Date;
+  subkeys: KeyOptions[]; // required unlike KeyOptions.subkeys
+}
+
+export interface Keyid {
+  bytes: string;
+}
+
+export interface DecryptMessageResult {
+  data: MaybeStream<Data>;
+  signatures: VerificationResult[];
+  filename: string;
+}
+
+export interface VerifyMessageResult {
+  data: MaybeStream<Data>;
+  signatures: VerificationResult[];
+}
+
+
+/**
+ * Armor an OpenPGP binary packet block
+ */
+export function armor(messagetype: enums.armor, body: object, partindex: number, parttotal: number): string;
+
+/**
+ * DeArmor an OpenPGP armored message; verify the checksum and return the encoded bytes
+ */
+export function unarmor(text: string): Promise<{ text: string, data: Stream<Uint8Array>, type: enums.armor }>;
+
+export class HKP {
+  constructor(keyServerBaseUrl?: string);
+  public lookup(options: { keyid?: string, query?: string }): Promise<string | undefined>;
+}
+
+/* ############## v5 ENUMS #################### */
+
+export namespace enums {
+
+  function read(type: typeof armor, e: armor): armorNames | string | any;
+  function read(type: typeof compression, e: compression): compressionNames | string | any;
+  function read(type: typeof hash, e: hash): hashNames | string | any;
+  function read(type: typeof packet, e: packet): packetNames | string | any;
+  function read(type: typeof publicKey, e: publicKey): publicKeyNames | string | any;
+  function read(type: typeof symmetric, e: symmetric): symmetricNames | string | any;
+  function read(type: typeof keyStatus, e: keyStatus): keyStatusNames | string | any;
+  function read(type: typeof keyFlags, e: keyFlags): keyFlagsNames | string | any;
+
+  export type armorNames = 'multipartSection' | 'multipartLast' | 'signed' | 'message' | 'publicKey' | 'privateKey';
+  enum armor {
+    multipartSection = 0,
+    multipartLast = 1,
+    signed = 2,
+    message = 3,
+    publicKey = 4,
+    privateKey = 5,
+    signature = 6,
+  }
+
+  enum reasonForRevocation {
+    noReason = 0, // No reason specified (key revocations or cert revocations)
+    keySuperseded = 1, // Key is superseded (key revocations)
+    keyCompromised = 2, // Key material has been compromised (key revocations)
+    keyRetired = 3, // Key is retired and no longer used (key revocations)
+    useridInvalid = 32, // User ID information is no longer valid (cert revocations)
+  }
+
+  export type compressionNames = 'uncompressed' | 'zip' | 'zlib' | 'bzip2';
+  enum compression {
+    uncompressed = 0,
+    zip = 1,
+    zlib = 2,
+    bzip2 = 3,
+  }
+
+  export type hashNames = 'md5' | 'sha1' | 'ripemd' | 'sha256' | 'sha384' | 'sha512' | 'sha224';
+  enum hash {
+    md5 = 1,
+    sha1 = 2,
+    ripemd = 3,
+    sha256 = 8,
+    sha384 = 9,
+    sha512 = 10,
+    sha224 = 11,
+  }
+
+  export type packetNames = 'publicKeyEncryptedSessionKey' | 'signature' | 'symEncryptedSessionKey' | 'onePassSignature' | 'secretKey' | 'publicKey'
+    | 'secretSubkey' | 'compressed' | 'symmetricallyEncrypted' | 'marker' | 'literal' | 'trust' | 'userid' | 'publicSubkey' | 'userAttribute'
+    | 'symEncryptedIntegrityProtected' | 'modificationDetectionCode' | 'AEADEncryptedDataPacket';
+  enum packet {
+    publicKeyEncryptedSessionKey = 1,
+    signature = 2,
+    symEncryptedSessionKey = 3,
+    onePassSignature = 4,
+    secretKey = 5,
+    publicKey = 6,
+    secretSubkey = 7,
+    compressedData = 8,
+    symmetricallyEncryptedData = 9,
+    marker = 10,
+    literalData = 11,
+    trust = 12,
+    userID = 13,
+    publicSubkey = 14,
+    userAttribute = 17,
+    symEncryptedIntegrityProtectedData = 18,
+    modificationDetectionCode = 19,
+    AEADEncryptedData = 20,
+  }
+
+  export type publicKeyNames = 'rsaEncryptSign' | 'rsaEncrypt' | 'rsaSign' | 'elgamal' | 'dsa' | 'ecdh' | 'ecdsa' | 'eddsa' | 'aedh' | 'aedsa';
+  enum publicKey {
+    rsaEncryptSign = 1,
+    rsaEncrypt = 2,
+    rsaSign = 3,
+    elgamal = 16,
+    dsa = 17,
+    ecdh = 18,
+    ecdsa = 19,
+    eddsa = 22,
+    aedh = 23,
+    aedsa = 24,
+  }
+
+  export type symmetricNames = 'plaintext' | 'idea' | 'tripledes' | 'cast5' | 'blowfish' | 'aes128' | 'aes192' | 'aes256' | 'twofish';
+  enum symmetric {
+    plaintext = 0,
+    idea = 1,
+    tripledes = 2,
+    cast5 = 3,
+    blowfish = 4,
+    aes128 = 7,
+    aes192 = 8,
+    aes256 = 9,
+    twofish = 10,
+  }
+
+  export type keyStatusNames = 'invalid' | 'expired' | 'revoked' | 'valid' | 'noSelfCert';
+  enum keyStatus {
+    invalid = 0,
+    expired = 1,
+    revoked = 2,
+    valid = 3,
+    noSelfCert = 4,
+  }
+
+  export type keyFlagsNames = 'certifyKeys' | 'signData' | 'encryptCommunication' | 'encryptStorage' | 'splitPrivateKey' | 'authentication'
+    | 'sharedPrivateKey';
+  enum keyFlags {
+    certifyKeys = 1,
+    signData = 2,
+    encryptCommunication = 4,
+    encryptStorage = 8,
+    splitPrivateKey = 16,
+    authentication = 32,
+    sharedPrivateKey = 128,
+  }
+
+}
+
+/* ############## v5 UTIL #################### */
+
+export namespace util {
+  /** Convert a string of utf8 bytes to a native javascript string
+      @param utf8 A valid squence of utf8 bytes
+  */
+  function decodeUtf8(utf8: string): string;
+
+  /** Convert a native javascript string to a string of utf8 bytes
+      param str The string to convert
+  */
+  function encodeUtf8(str: string): string;
+
+  /** Get native Web Cryptography api. The default configuration is to use the api when available. But it can also be deactivated with config.useWebCrypto
+   */
+  function getWebCrypto(): object;
+
+  /** Helper function to print a debug message. Debug messages are only printed if
+      @param str string of the debug message
+  */
+  function printDebug(str: string): void;
+
+  /** Helper function to print a debug message. Debug messages are only printed if
+      @param str string of the debug message
+  */
+  function printDebugHexstrDump(str: string): void;
+
+  /** Shifting a string to n bits right
+      @param value The string to shift
+      @param bitcount Amount of bits to shift (MUST be smaller than 9)
+  */
+  function shiftRight(value: string, bitcount: number): string;
+
+  /**
+   * Convert a string to an array of 8-bit integers
+   * @param {String} str String to convert
+   * @returns {Uint8Array} An array of 8-bit integers
+   */
+  function strToUint8Array(str: string): Uint8Array;
+
+  /**
+   * Convert an array of 8-bit integers to a string
+   * @param {Uint8Array} bytes An array of 8-bit integers to convert
+   * @returns {String} String representation of the array
+   */
+  function uint8ArrayToStr(bin: Uint8Array): string;
+
+  /**
+   * Convert an array of 8-bit integers to a hex string
+   * @param {Uint8Array} bytes Array of 8-bit integers to convert
+   * @returns {String} Hexadecimal representation of the array
+   */
+  function uint8ArrayToHex(bytes: Uint8Array): string;
+
+  function uint8ArrayToB64(bytes: Uint8Array): string;
+
+  function uint8ArrayToMpi(bytes: Uint8Array): Uint8Array;
+
+  /**
+   * Convert a hex string to an array of 8-bit integers
+   * @param {String} hex  A hex string to convert
+   * @returns {Uint8Array} An array of 8-bit integers
+   */
+  function hexToUint8Array(hex: string): Uint8Array;
+
+  /**
+   * Create hex string from a binary
+   * @param {String} str String to convert
+   * @returns {String} String containing the hexadecimal values
+   */
+  function strToHex(str: string): string;
+
+  /**
+   * Create binary string from a hex encoded string
+   * @param {String} str Hex string to convert
+   * @returns {String}
+   */
+  function hexToStr(hex: string): string;
+
+  function parseUserId(userid: string): UserId;
+
+  function formatUserId(userid: UserId): string;
+
+  function normalizeDate(date: Date | null): Date | null;
+
+  /**
+   * Encode input buffer using Z-Base32 encoding.
+   * See: https://tools.ietf.org/html/rfc6189#section-5.1.6
+   *
+   * @param {Uint8Array} data The binary data to encode
+   * @returns {String} Binary data encoded using Z-Base32
+   */
+  function encodeZBase32(data: Uint8Array): string;
+}
diff --git a/package-lock.json b/package-lock.json
index 125b1644..98cdbc1a 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -322,6 +322,12 @@
       "integrity": "sha512-+iTbntw2IZPb/anVDbypzfQa+ay64MW0Zo8aJ8gZPWMMK6/OubMVb6lUPMagqjOPnmtauXnFCACVl3O7ogjeqQ==",
       "dev": true
     },
+    "@types/chai": {
+      "version": "4.2.14",
+      "resolved": "https://registry.npmjs.org/@types/chai/-/chai-4.2.14.tgz",
+      "integrity": "sha512-G+ITQPXkwTrslfG5L/BksmbLUA0M1iybEsmCWPqzSxsRRhJZimBKJkoMi8fr/CPygPTj4zO5pJH7I2/cm9M7SQ==",
+      "dev": true
+    },
     "@types/estree": {
       "version": "0.0.39",
       "resolved": "https://registry.npmjs.org/@types/estree/-/estree-0.0.39.tgz",
@@ -3789,6 +3795,12 @@
       "integrity": "sha1-hnrHTjhkGHsdPUfZlqeOxciDB3c=",
       "dev": true
     },
+    "typescript": {
+      "version": "4.1.2",
+      "resolved": "https://registry.npmjs.org/typescript/-/typescript-4.1.2.tgz",
+      "integrity": "sha512-thGloWsGH3SOxv1SoY7QojKi0tc+8FnOmiarEGMbd/lar7QOEd3hvlx3Fp5y6FlDUGl9L+pd4n2e+oToGMmhRQ==",
+      "dev": true
+    },
     "uc.micro": {
       "version": "1.0.6",
       "resolved": "https://registry.npmjs.org/uc.micro/-/uc.micro-1.0.6.tgz",
diff --git a/package.json b/package.json
index 0b1926d4..212e94c7 100644
--- a/package.json
+++ b/package.json
@@ -19,12 +19,14 @@
     "./dist/node/openpgp.min.js": "./dist/openpgp.min.js",
     "./dist/node/openpgp.min.mjs": "./dist/openpgp.min.mjs"
   },
+  "types": "openpgp.d.ts",
   "directories": {
     "lib": "src"
   },
   "files": [
     "dist/",
-    "lightweight/"
+    "lightweight/",
+    "openpgp.d.ts"
   ],
   "esm": {
     "cjs": {
@@ -36,6 +38,7 @@
     "build-test": "npm run build --build-only=test",
     "prepare": "npm run build",
     "test": "mocha --require esm --timeout 120000 test/unittests.js",
+    "test-type-definitions": "tsc test/typescript/definitions.ts && node test/typescript/definitions.js",
     "start": "http-server",
     "prebrowsertest": "npm run build-test",
     "browsertest": "npm start -- -o test/unittests.html",
@@ -51,6 +54,7 @@
     "@rollup/plugin-commonjs": "^11.1.0",
     "@rollup/plugin-node-resolve": "^7.1.3",
     "@rollup/plugin-replace": "^2.3.2",
+    "@types/chai": "^4.2.14",
     "asmcrypto.js": "github:openpgpjs/asmcrypto#5b994303a9d3e27e0915f72a10b6c2c51535a4dc",
     "babel-eslint": "^10.1.0",
     "bn.js": "^4.11.8",
@@ -77,6 +81,7 @@
     "sinon": "^4.3.0",
     "text-encoding-utf-8": "^1.0.2",
     "tweetnacl": "github:openpgpjs/tweetnacl-js#3dae25bd3eaa77173f3405676b595721dde92eec",
+    "typescript": "^4.1.2",
     "web-stream-tools": "github:openpgpjs/web-stream-tools#5e6cb1a976d50c421091907615cf7cce77ac4f2a",
     "whatwg-fetch": "^2.0.3"
   },
diff --git a/test/typescript/definitions.ts b/test/typescript/definitions.ts
new file mode 100644
index 00000000..86a0c180
--- /dev/null
+++ b/test/typescript/definitions.ts
@@ -0,0 +1,117 @@
+/**
+ * npm run-script test-type-definitions
+ * 
+ * If types are off, either this will fail to build with TypeScript, or it will fail to run.
+ *  - if it fails to build, edit the file to match type definitions
+ *  - if it fails to run, edit this file to match the actual library API, then edit the definitions file (openpgp.d.ts) accordingly.
+ */
+
+import { generateKey, readArmoredKey, readArmoredKeys, Key, readMessage, readArmoredMessage, Message, CleartextMessage, encrypt, decrypt, sign, verify } from '../..';
+import { expect } from 'chai';
+
+(async () => {
+
+  // Generate keys
+  const { publicKeyArmored, key } = await generateKey({ userIds: [{ email: "user@corp.co" }] });
+  expect(key).to.be.instanceOf(Key);
+  const privateKeys = [key];
+  const publicKeys = [key.toPublic()];
+
+  // Parse keys
+  expect(await readArmoredKey(publicKeyArmored)).to.be.instanceOf(Key);
+  expect(await readArmoredKeys(publicKeyArmored)).to.have.lengthOf(1);
+
+  // Encrypt text message (armored)
+  const text = 'hello';
+  const textMessage = Message.fromText('hello');
+  const encryptedArmor: string = await encrypt({ publicKeys, message: textMessage });
+  expect(encryptedArmor).to.include('-----BEGIN PGP MESSAGE-----');
+
+  // Encrypt binary message (unarmored)
+  const binary = new Uint8Array(2);
+  binary[0] = 1;
+  binary[1] = 2;
+  const binaryMessage = Message.fromBinary(binary);
+  const encryptedBinary: Uint8Array = await encrypt({ publicKeys, message: binaryMessage, armor: false });
+  expect(encryptedBinary).to.be.instanceOf(Uint8Array);
+
+  // Decrypt text message (armored)
+  const encryptedTextMessage = await readArmoredMessage(encryptedArmor);
+  const decryptedText = await decrypt({ privateKeys, message: encryptedTextMessage });
+  const decryptedTextData: string = decryptedText.data;
+  expect(decryptedTextData).to.equal(text);
+
+  // Decrypt binary message (unarmored)
+  const encryptedBinaryMessage = await readMessage(encryptedBinary);
+  const decryptedBinary = await decrypt({ privateKeys, message: encryptedBinaryMessage, format: 'binary' });
+  const decryptedBinaryData: Uint8Array = decryptedBinary.data;
+  expect(decryptedBinaryData).to.deep.equal(binary);
+
+  // Encrypt message (inspect packets)
+  const encryptedMessage = await readMessage(encryptedBinary);
+  expect(encryptedMessage).to.be.instanceOf(Message);
+
+  // Sign cleartext message (armored)
+  const cleartextMessage = CleartextMessage.fromText('hello');
+  const clearSignedArmor = await sign({ privateKeys, message: cleartextMessage });
+  expect(clearSignedArmor).to.include('-----BEGIN PGP SIGNED MESSAGE-----');
+
+  // Sign text message (armored)
+  const textSignedArmor: string = await sign({ privateKeys, message: textMessage });
+  expect(textSignedArmor).to.include('-----BEGIN PGP MESSAGE-----');
+
+  // Sign text message (unarmored)
+  const textSignedBinary: Uint8Array = await sign({ privateKeys, message: binaryMessage, armor: false });
+  expect(textSignedBinary).to.be.instanceOf(Uint8Array);
+
+  // Verify signed text message (armored)
+  const signedMessage = await readArmoredMessage(textSignedArmor);
+  const verifiedText = await verify({ publicKeys, message: signedMessage });
+  const verifiedTextData: string = verifiedText.data;
+  expect(verifiedTextData).to.equal(text);
+
+  // Verify signed binary message (unarmored)
+  const message = await readMessage(textSignedBinary);
+  const verifiedBinary = await verify({ publicKeys, message, format: 'binary' });
+  const verifiedBinaryData: Uint8Array = verifiedBinary.data;
+  expect(verifiedBinaryData).to.deep.equal(binary);
+
+  // // Detached - sign cleartext message (armored)
+  // import { Message, sign } from 'openpgp';
+  // const message = Message.fromText(util.removeTrailingSpaces(text));
+  // const signed = await sign({ privateKeys, message, detached: true });
+  // console.log(signed); // String
+
+  // // Detached - sign binary message (unarmored)
+  // const message = Message.fromText(text);
+  // const signed = await sign({ privateKeys, message, detached: true, armor: false });
+  // console.log(signed); // Uint8Array
+
+  // // Encrypt session keys (armored)
+  // const encrypted = await encryptSessionKey({ publicKeys, data, algorithm });
+  // console.log(encrypted); // String
+
+  // // Encrypt session keys (unarmored)
+  // const encrypted = await encryptSessionKey({ publicKeys, data, algorithm, armor: false });
+  // console.log(encrypted); // Uint8Array
+
+  // // Streaming - encrypt text message on Node.js (armored)
+  // const data = fs.createReadStream(filename, { encoding: 'utf8' });
+  // const message = Message.fromText(data);
+  // const encrypted = await encrypt({ publicKeys, message });
+  // encrypted.on('data', chunk => {
+  //   console.log(chunk); // String
+  // });
+
+  // // Streaming - encrypt binary message on Node.js (unarmored)
+  // const data = fs.createReadStream(filename);
+  // const message = Message.fromBinary(data);
+  // const encrypted = await encrypt({ publicKeys, message, armor: false });
+  // encrypted.pipe(targetStream);
+
+  console.log('TypeScript definitions are correct');
+})().catch(e => {
+  console.error('TypeScript definitions tests failed by throwing the following error');
+  console.error(e);
+  process.exit(1);
+});
diff --git a/travis.sh b/travis.sh
index 065a1d52..bac508ed 100755
--- a/travis.sh
+++ b/travis.sh
@@ -11,6 +11,10 @@ elif [ $OPENPGPJSTEST = "lint" ]; then
   echo "Running OpenPGP.js eslint."
   npm run lint
 
+elif [ $OPENPGPJSTEST = "test-type-definitions" ]; then
+  echo "Testing OpenPGP.js type definitions."
+  npm run test-type-definitions
+
 elif [ $OPENPGPJSTEST = "unit" ]; then
   echo "Running OpenPGP.js unit tests on node.js."
   npm test ${LIGHTWEIGHT+ -- --grep lightweight}
diff --git a/tsconfig.json b/tsconfig.json
new file mode 100644
index 00000000..60f1e065
--- /dev/null
+++ b/tsconfig.json
@@ -0,0 +1,8 @@
+{
+  "exclude": [
+    "./build/"
+  ],
+  "compilerOptions": {
+    "strict": true
+  }
+}