diff --git a/types/lib/condition.d.ts b/types/lib/condition.d.ts
index 6672987..680d4b1 100644
--- a/types/lib/condition.d.ts
+++ b/types/lib/condition.d.ts
@@ -1,4 +1,4 @@
-import { Asn1Json, TypeAsn1Condition } from '../types';
+import { TypeAsn1Condition } from '../types';
 
 export interface ConditionAsn1Json {
   type: TypeAsn1Condition;
@@ -54,7 +54,7 @@ export default class Condition {
 
   serializeBinary(): Buffer;
 
-  getAsn1Json(): Asn1Json;
+  getAsn1Json(): ConditionAsn1Json;
 
   validate(): boolean;
 }
diff --git a/types/lib/fulfillment.d.ts b/types/lib/fulfillment.d.ts
index 4c20375..9b02095 100644
--- a/types/lib/fulfillment.d.ts
+++ b/types/lib/fulfillment.d.ts
@@ -6,7 +6,9 @@ import {
   ThresholdSha256Json,
   TypeAsn1Fulfillment,
   TypeName,
+  TypeId,
 } from '../types';
+import Condition from './condition';
 
 interface FulfillmentAsn1JsonValueMap {
   [TypeAsn1Fulfillment.PreimageSha256]: PreimageSha256Json;
@@ -32,7 +34,7 @@ export default class Fulfillment {
     json: PreimageSha256Json | PrefixSha256Json | ThresholdSha256Json | RsaSha256Json | Ed25519Sha256Json
   ): Fulfillment;
 
-  getTypeId(): TypeIds;
+  getTypeId(): TypeId;
 
   getTypeName(): TypeName;
 
@@ -60,5 +62,5 @@ export default class Fulfillment {
 
   serializeBase64Url(): string;
 
-  validate(): boolean;
+  validate(message?: Buffer): boolean;
 }
diff --git a/types/types/ed25519-sha256.d.ts b/types/types/ed25519-sha256.d.ts
index 901b28a..832132d 100644
--- a/types/types/ed25519-sha256.d.ts
+++ b/types/types/ed25519-sha256.d.ts
@@ -9,17 +9,25 @@ import type {
 } from '.';
 import type BaseSha256 from './base-sha256';
 
+export const TYPE_ID: TypeId.Ed25519Sha256;
+export const TYPE_NAME: TypeName.Ed25519Sha256;
+export const TYPE_ASN1_CONDITION: TypeAsn1Condition.Ed25519Sha256;
+export const TYPE_ASN1_FULFILLMENT: TypeAsn1Fulfillment.Ed25519Sha256;
+export const TYPE_CATEGORY: TypeCategory.Ed25519Sha256;
+
+export const TYPE_ID = TypeId.Ed25519Sha256;
+export const CONSTANT_COST = 131072;
 export default class Ed25519Sha256 extends BaseSha256 {
   private publicKey: Buffer;
   private signature: Buffer;
 
-  static TYPE_ID = TypeId.Ed25519Sha256;
-  static TYPE_NAME = TypeName.Ed25519Sha256;
-  static TYPE_ASN1_CONDITION = TypeAsn1Condition.Ed25519Sha256;
-  static TYPE_ASN1_FULFILLMENT = TypeAsn1Fulfillment.Ed25519Sha256;
-  static TYPE_CATEGORY = TypeCategory.Ed25519Sha256;
+  static TYPE_ID: TypeId.Ed25519Sha256;
+  static TYPE_NAME: TypeName.Ed25519Sha256;
+  static TYPE_ASN1_CONDITION: TypeAsn1Condition.Ed25519Sha256;
+  static TYPE_ASN1_FULFILLMENT: TypeAsn1Fulfillment.Ed25519Sha256;
+  static TYPE_CATEGORY: TypeCategory.Ed25519Sha256;
 
-  static CONSTANT_COST = 131072;
+  static CONSTANT_COST: number;
 
   constructor();
 
diff --git a/types/types/prefix-sha256.d.ts b/types/types/prefix-sha256.d.ts
index 8602d1f..91f8eb4 100644
--- a/types/types/prefix-sha256.d.ts
+++ b/types/types/prefix-sha256.d.ts
@@ -11,19 +11,28 @@ import type Condition from '../lib/condition';
 import type Fulfillment from '../lib/fulfillment';
 import type BaseSha256 from './base-sha256';
 
+export const TYPE_ID = TypeId.PrefixSha256;
+export const TYPE_NAME: TypeName.PrefixSha256;
+export const TYPE_ASN1_CONDITION: TypeAsn1Condition.PrefixSha256;
+export const TYPE_ASN1_FULFILLMENT: TypeAsn1Fulfillment.PrefixSha256;
+export const TYPE_CATEGORY: TypeCategory.PrefixSha256;
+
+export const CONSTANT_BASE_COST = 16384;
+export const CONSTANT_COST_DIVISOR = 256;
+
 export default class PrefixSha256 extends BaseSha256 {
   private prefix: Buffer;
   private subcondition: Condition | Fulfillment;
   private maxMessageLength: number;
 
-  static TYPE_ID = TypeId.PrefixSha256;
-  static TYPE_NAME = TypeName.PrefixSha256;
-  static TYPE_ASN1_CONDITION = TypeAsn1Condition.PrefixSha256;
-  static TYPE_ASN1_FULFILLMENT = TypeAsn1Fulfillment.PrefixSha256;
-  static TYPE_CATEGORY = TypeCategory.PrefixSha256;
+  static TYPE_ID: TypeId.PrefixSha256;
+  static TYPE_NAME: TypeName.PrefixSha256;
+  static TYPE_ASN1_CONDITION: TypeAsn1Condition.PrefixSha256;
+  static TYPE_ASN1_FULFILLMENT: TypeAsn1Fulfillment.PrefixSha256;
+  static TYPE_CATEGORY: TypeCategory.PrefixSha256;
 
-  static CONSTANT_BASE_COST = 16384;
-  static CONSTANT_COST_DIVISOR = 256;
+  static CONSTANT_BASE_COST: number;
+  static CONSTANT_COST_DIVISOR: number;
 
   constructor();
 
diff --git a/types/types/preimage-sha256.d.ts b/types/types/preimage-sha256.d.ts
index 2b5a341..98d994d 100644
--- a/types/types/preimage-sha256.d.ts
+++ b/types/types/preimage-sha256.d.ts
@@ -9,14 +9,20 @@ import type {
 } from '.';
 import type BaseSha256 from './base-sha256';
 
+export const TYPE_ID = TypeId.PreimageSha256;
+export const TYPE_NAME = TypeName.PreimageSha256;
+export const TYPE_ASN1_CONDITION = TypeAsn1Condition.PreimageSha256;
+export const TYPE_ASN1_FULFILLMENT = TypeAsn1Fulfillment.PreimageSha256;
+export const TYPE_CATEGORY = TypeCategory.PreimageSha256;
+
 export default class PreimageSha256 extends BaseSha256 {
   private preimage: Buffer;
 
-  static TYPE_ID = TypeId.PreimageSha256;
-  static TYPE_NAME = TypeName.PreimageSha256;
-  static TYPE_ASN1_CONDITION = TypeAsn1Condition.PreimageSha256;
-  static TYPE_ASN1_FULFILLMENT = TypeAsn1Fulfillment.PreimageSha256;
-  static TYPE_CATEGORY = TypeCategory.PreimageSha256;
+  static TYPE_ID: TypeId.PreimageSha256;
+  static TYPE_NAME: TypeName.PreimageSha256;
+  static TYPE_ASN1_CONDITION: TypeAsn1Condition.PreimageSha256;
+  static TYPE_ASN1_FULFILLMENT: TypeAsn1Fulfillment.PreimageSha256;
+  static TYPE_CATEGORY: TypeCategory.PreimageSha256;
 
   private getFingerprintContents(): Buffer;
 
diff --git a/types/types/rsa-sha256.d.ts b/types/types/rsa-sha256.d.ts
index 2a4c669..9e0209e 100644
--- a/types/types/rsa-sha256.d.ts
+++ b/types/types/rsa-sha256.d.ts
@@ -8,17 +8,25 @@ import type {
 } from '.';
 import type BaseSha256 from './base-sha256';
 
+export const TYPE_ID = TypeId.RsaSha256;
+export const TYPE_NAME = TypeName.RsaSha256;
+export const TYPE_ASN1_CONDITION = TypeAsn1Condition.RsaSha256;
+export const TYPE_ASN1_FULFILLMENT = TypeAsn1Fulfillment.RsaSha256;
+export const TYPE_CATEGORY = TypeCategory.RsaSha256;
+
+export const COST_RIGHT_SHIFT = 6; // 2^6 = 64
+
 export default class RsaSha256 extends BaseSha256 {
   private modulus: Buffer;
   private signature: Buffer;
 
-  static TYPE_ID = TypeId.RsaSha256;
-  static TYPE_NAME = TypeName.RsaSha256;
-  static TYPE_ASN1_CONDITION = TypeAsn1Condition.RsaSha256;
-  static TYPE_ASN1_FULFILLMENT = TypeAsn1Fulfillment.RsaSha256;
-  static TYPE_CATEGORY = TypeCategory.RsaSha256;
+  static TYPE_ID: TypeId.RsaSha256;
+  static TYPE_NAME: TypeName.RsaSha256;
+  static TYPE_ASN1_CONDITION: TypeAsn1Condition.RsaSha256;
+  static TYPE_ASN1_FULFILLMENT: TypeAsn1Fulfillment.RsaSha256;
+  static TYPE_CATEGORY: TypeCategory.RsaSha256;
 
-  static COST_RIGHT_SHIFT = 6; // 2^6 = 64
+  static COST_RIGHT_SHIFT: number;
 
   constructor();
 
diff --git a/types/types/threshold-sha256.d.ts b/types/types/threshold-sha256.d.ts
index cd93593..35a0831 100644
--- a/types/types/threshold-sha256.d.ts
+++ b/types/types/threshold-sha256.d.ts
@@ -11,8 +11,8 @@ import type Condition from '../lib/condition';
 import type Fulfillment from '../lib/fulfillment';
 import type BaseSha256 from './base-sha256';
 
-declare const CONDITION = 'condition';
-declare const FULFILLMENT = 'fulfillment';
+export const CONDITION = 'condition';
+export const FULFILLMENT = 'fulfillment';
 
 interface SubConditionBodyMap {
   condition: Condition;
@@ -24,15 +24,21 @@ export type SubCondition<T = 'condition' | 'fulfillment'> = {
   body: SubConditionBodyMap[T];
 };
 
+export const TYPE_ID = TypeId.ThresholdSha256;
+export const TYPE_NAME = TypeName.ThresholdSha256;
+export const TYPE_ASN1_CONDITION = TypeAsn1Condition.ThresholdSha256;
+export const TYPE_ASN1_FULFILLMENT = TypeAsn1Fulfillment.ThresholdSha256;
+export const TYPE_CATEGORY = TypeCategory.ThresholdSha256;
+
 export default class ThresholdSha256 extends BaseSha256 {
   private threshold: number;
   private subconditions: SubCondition[];
 
-  static TYPE_ID = TypeId.ThresholdSha256;
-  static TYPE_NAME = TypeName.ThresholdSha256;
-  static TYPE_ASN1_CONDITION = TypeAsn1Condition.ThresholdSha256;
-  static TYPE_ASN1_FULFILLMENT = TypeAsn1Fulfillment.ThresholdSha256;
-  static TYPE_CATEGORY = TypeCategory.ThresholdSha256;
+  static TYPE_ID: TypeId.ThresholdSha256;
+  static TYPE_NAME: TypeName.ThresholdSha256;
+  static TYPE_ASN1_CONDITION: TypeAsn1Condition.ThresholdSha256;
+  static TYPE_ASN1_FULFILLMENT: TypeAsn1Fulfillment.ThresholdSha256;
+  static TYPE_CATEGORY: TypeCategory.ThresholdSha256;
 
   constructor();