diff --git a/packages/core/src/decorators/attachment/Attachment.test.ts b/packages/core/src/decorators/attachment/Attachment.test.ts
index 8f21c58ccd..b983de2a53 100644
--- a/packages/core/src/decorators/attachment/Attachment.test.ts
+++ b/packages/core/src/decorators/attachment/Attachment.test.ts
@@ -1,6 +1,7 @@
-import { JsonTransformer } from '../..'
+import { JsonEncoder } from '../../utils/JsonEncoder'
+import { JsonTransformer } from '../../utils/JsonTransformer'
 
-import { Attachment } from './Attachment'
+import { Attachment, AttachmentData } from './Attachment'
 
 const mockJson = {
   '@id': 'ceffce22-6471-43e4-8945-b604091981c9',
@@ -17,6 +18,18 @@ const mockJson = {
   },
 }
 
+const mockJsonBase64 = {
+  '@id': 'ceffce22-6471-43e4-8945-b604091981c9',
+  description: 'A small picture of a cat',
+  filename: 'cat.png',
+  'mime-type': 'text/plain',
+  lastmod_time: new Date(),
+  byte_count: 9200,
+  data: {
+    base64: JsonEncoder.toBase64(mockJson.data.json),
+  },
+}
+
 const id = 'ceffce22-6471-43e4-8945-b604091981c9'
 const description = 'A small picture of a cat'
 const filename = 'cat.png'
@@ -29,6 +42,7 @@ const data = {
   },
   sha256: '00d7b2068a0b237f14a7979bbfc01ad62f60792e459467bfc4a7d3b9a6dbbe3e',
 }
+const dataInstance = new AttachmentData(data)
 
 describe('Decorators | Attachment', () => {
   it('should correctly transform Json to Attachment class', () => {
@@ -39,7 +53,7 @@ describe('Decorators | Attachment', () => {
     expect(decorator.filename).toBe(mockJson.filename)
     expect(decorator.lastmodTime).toEqual(mockJson.lastmod_time)
     expect(decorator.byteCount).toEqual(mockJson.byte_count)
-    expect(decorator.data).toEqual(mockJson.data)
+    expect(decorator.data).toMatchObject(mockJson.data)
   })
 
   it('should correctly transform Attachment class to Json', () => {
@@ -50,7 +64,7 @@ describe('Decorators | Attachment', () => {
       mimeType,
       lastmodTime,
       byteCount,
-      data,
+      data: dataInstance,
     })
 
     const json = JsonTransformer.toJSON(decorator)
@@ -64,6 +78,20 @@ describe('Decorators | Attachment', () => {
       data,
     }
 
-    expect(json).toEqual(transformed)
+    expect(json).toMatchObject(transformed)
+  })
+
+  it('should return the data correctly if only JSON exists', () => {
+    const decorator = JsonTransformer.fromJSON(mockJson, Attachment)
+
+    const gotData = decorator.data.getDataAsJson()
+    expect(decorator.data.json).toEqual(gotData)
+  })
+
+  it('should return the data correctly if only Base64 exists', () => {
+    const decorator = JsonTransformer.fromJSON(mockJsonBase64, Attachment)
+
+    const gotData = decorator.data.getDataAsJson()
+    expect(mockJson.data.json).toEqual(gotData)
   })
 })
diff --git a/packages/core/src/decorators/attachment/Attachment.ts b/packages/core/src/decorators/attachment/Attachment.ts
index 5dea2fb778..24044e9d05 100644
--- a/packages/core/src/decorators/attachment/Attachment.ts
+++ b/packages/core/src/decorators/attachment/Attachment.ts
@@ -11,6 +11,8 @@ import {
   ValidateNested,
 } from 'class-validator'
 
+import { AriesFrameworkError } from '../../error'
+import { JsonEncoder } from '../../utils/JsonEncoder'
 import { uuid } from '../../utils/uuid'
 
 export interface AttachmentOptions {
@@ -45,6 +47,19 @@ export class AttachmentData {
     }
   }
 
+  /*
+   * Helper function returning JSON representation of attachment data (if present). Tries to obtain the data from .base64 or .json, throws an error otherwise
+   */
+  public getDataAsJson<T>(): T {
+    if (typeof this.base64 === 'string') {
+      return JsonEncoder.fromBase64(this.base64) as T
+    } else if (this.json) {
+      return this.json as T
+    } else {
+      throw new AriesFrameworkError('No attachment data found in `json` or `base64` data fields.')
+    }
+  }
+
   /**
    * Base64-encoded data, when representing arbitrary content inline instead of via links. Optional.
    */
diff --git a/packages/core/src/modules/credentials/CredentialResponseCoordinator.ts b/packages/core/src/modules/credentials/CredentialResponseCoordinator.ts
index d076596061..a463555665 100644
--- a/packages/core/src/modules/credentials/CredentialResponseCoordinator.ts
+++ b/packages/core/src/modules/credentials/CredentialResponseCoordinator.ts
@@ -133,7 +133,7 @@ export class CredentialResponseCoordinator {
       const indyCredential = credentialRecord.credentialMessage.indyCredential
 
       if (!indyCredential) {
-        this.agentConfig.logger.error(`Missing required base64 encoded attachment data for credential`)
+        this.agentConfig.logger.error(`Missing required base64 or json encoded attachment data for credential`)
         return false
       }
 
diff --git a/packages/core/src/modules/credentials/__tests__/CredentialService.test.ts b/packages/core/src/modules/credentials/__tests__/CredentialService.test.ts
index c7eba091c2..411056df7e 100644
--- a/packages/core/src/modules/credentials/__tests__/CredentialService.test.ts
+++ b/packages/core/src/modules/credentials/__tests__/CredentialService.test.ts
@@ -587,7 +587,7 @@ describe('CredentialService', () => {
           })
         )
       ).rejects.toThrowError(
-        `Missing required base64 encoded attachment data for credential request with thread id ${threadId}`
+        `Missing required base64 or json encoded attachment data for credential request with thread id ${threadId}`
       )
     })
 
diff --git a/packages/core/src/modules/credentials/messages/IssueCredentialMessage.ts b/packages/core/src/modules/credentials/messages/IssueCredentialMessage.ts
index aab5a37e84..c5e4689137 100644
--- a/packages/core/src/modules/credentials/messages/IssueCredentialMessage.ts
+++ b/packages/core/src/modules/credentials/messages/IssueCredentialMessage.ts
@@ -5,7 +5,6 @@ import { Equals, IsArray, IsInstance, IsOptional, IsString, ValidateNested } fro
 
 import { AgentMessage } from '../../../agent/AgentMessage'
 import { Attachment } from '../../../decorators/attachment/Attachment'
-import { JsonEncoder } from '../../../utils/JsonEncoder'
 
 export const INDY_CREDENTIAL_ATTACHMENT_ID = 'libindy-cred-0'
 
@@ -48,13 +47,8 @@ export class IssueCredentialMessage extends AgentMessage {
   public get indyCredential(): Cred | null {
     const attachment = this.credentialAttachments.find((attachment) => attachment.id === INDY_CREDENTIAL_ATTACHMENT_ID)
 
-    // Return null if attachment is not found
-    if (!attachment?.data?.base64) {
-      return null
-    }
-
     // Extract credential from attachment
-    const credentialJson = JsonEncoder.fromBase64(attachment.data.base64)
+    const credentialJson = attachment?.data?.getDataAsJson<Cred>() ?? null
 
     return credentialJson
   }
diff --git a/packages/core/src/modules/credentials/messages/OfferCredentialMessage.ts b/packages/core/src/modules/credentials/messages/OfferCredentialMessage.ts
index 5736a9a26f..c1b1953e8d 100644
--- a/packages/core/src/modules/credentials/messages/OfferCredentialMessage.ts
+++ b/packages/core/src/modules/credentials/messages/OfferCredentialMessage.ts
@@ -5,7 +5,6 @@ import { Equals, IsArray, IsInstance, IsOptional, IsString, ValidateNested } fro
 
 import { AgentMessage } from '../../../agent/AgentMessage'
 import { Attachment } from '../../../decorators/attachment/Attachment'
-import { JsonEncoder } from '../../../utils/JsonEncoder'
 
 import { CredentialPreview } from './CredentialPreview'
 
@@ -63,13 +62,8 @@ export class OfferCredentialMessage extends AgentMessage {
   public get indyCredentialOffer(): CredOffer | null {
     const attachment = this.offerAttachments.find((attachment) => attachment.id === INDY_CREDENTIAL_OFFER_ATTACHMENT_ID)
 
-    // Return null if attachment is not found
-    if (!attachment?.data?.base64) {
-      return null
-    }
-
     // Extract credential offer from attachment
-    const credentialOfferJson = JsonEncoder.fromBase64(attachment.data.base64)
+    const credentialOfferJson = attachment?.data?.getDataAsJson<CredOffer>() ?? null
 
     return credentialOfferJson
   }
diff --git a/packages/core/src/modules/credentials/messages/RequestCredentialMessage.ts b/packages/core/src/modules/credentials/messages/RequestCredentialMessage.ts
index 2600a44cac..e377f6b5f8 100644
--- a/packages/core/src/modules/credentials/messages/RequestCredentialMessage.ts
+++ b/packages/core/src/modules/credentials/messages/RequestCredentialMessage.ts
@@ -5,7 +5,6 @@ import { Equals, IsArray, IsInstance, IsOptional, IsString, ValidateNested } fro
 
 import { AgentMessage } from '../../../agent/AgentMessage'
 import { Attachment } from '../../../decorators/attachment/Attachment'
-import { JsonEncoder } from '../../../utils/JsonEncoder'
 
 export const INDY_CREDENTIAL_REQUEST_ATTACHMENT_ID = 'libindy-cred-request-0'
 
@@ -49,14 +48,8 @@ export class RequestCredentialMessage extends AgentMessage {
     const attachment = this.requestAttachments.find(
       (attachment) => attachment.id === INDY_CREDENTIAL_REQUEST_ATTACHMENT_ID
     )
-
-    // Return null if attachment is not found
-    if (!attachment?.data?.base64) {
-      return null
-    }
-
     // Extract proof request from attachment
-    const credentialReqJson = JsonEncoder.fromBase64(attachment.data.base64)
+    const credentialReqJson = attachment?.data?.getDataAsJson<CredReq>() ?? null
 
     return credentialReqJson
   }
diff --git a/packages/core/src/modules/credentials/services/CredentialService.ts b/packages/core/src/modules/credentials/services/CredentialService.ts
index 6537c1a266..30ca9d6fab 100644
--- a/packages/core/src/modules/credentials/services/CredentialService.ts
+++ b/packages/core/src/modules/credentials/services/CredentialService.ts
@@ -357,7 +357,7 @@ export class CredentialService {
     const indyCredentialOffer = credentialOfferMessage.indyCredentialOffer
     if (!indyCredentialOffer) {
       throw new CredentialProblemReportError(
-        `Missing required base64 encoded attachment data for credential offer with thread id ${credentialOfferMessage.threadId}`,
+        `Missing required base64 or json encoded attachment data for credential offer with thread id ${credentialOfferMessage.threadId}`,
         { problemCode: CredentialProblemReportReason.IssuanceAbandoned }
       )
     }
@@ -433,7 +433,7 @@ export class CredentialService {
 
     if (!credentialOffer) {
       throw new CredentialProblemReportError(
-        `Missing required base64 encoded attachment data for credential offer with thread id ${credentialRecord.threadId}`,
+        `Missing required base64 or json encoded attachment data for credential offer with thread id ${credentialRecord.threadId}`,
         { problemCode: CredentialProblemReportReason.IssuanceAbandoned }
       )
     }
@@ -494,7 +494,7 @@ export class CredentialService {
 
     if (!indyCredentialRequest) {
       throw new CredentialProblemReportError(
-        `Missing required base64 encoded attachment data for credential request with thread id ${credentialRequestMessage.threadId}`,
+        `Missing required base64 or json encoded attachment data for credential request with thread id ${credentialRequestMessage.threadId}`,
         { problemCode: CredentialProblemReportReason.IssuanceAbandoned }
       )
     }
@@ -554,7 +554,7 @@ export class CredentialService {
     const indyCredentialOffer = offerMessage?.indyCredentialOffer
     if (!indyCredentialOffer) {
       throw new CredentialProblemReportError(
-        `Missing required base64 encoded attachment data for credential offer with thread id ${credentialRecord.threadId}`,
+        `Missing required base64 or json encoded attachment data for credential offer with thread id ${credentialRecord.threadId}`,
         { problemCode: CredentialProblemReportReason.IssuanceAbandoned }
       )
     }
@@ -563,7 +563,7 @@ export class CredentialService {
     const indyCredentialRequest = requestMessage?.indyCredentialRequest
     if (!indyCredentialRequest) {
       throw new CredentialProblemReportError(
-        `Missing required base64 encoded attachment data for credential request with thread id ${credentialRecord.threadId}`,
+        `Missing required base64 or json encoded attachment data for credential request with thread id ${credentialRecord.threadId}`,
         { problemCode: CredentialProblemReportReason.IssuanceAbandoned }
       )
     }
@@ -641,7 +641,7 @@ export class CredentialService {
     const indyCredential = issueCredentialMessage.indyCredential
     if (!indyCredential) {
       throw new CredentialProblemReportError(
-        `Missing required base64 encoded attachment data for credential with thread id ${issueCredentialMessage.threadId}`,
+        `Missing required base64 or json encoded attachment data for credential with thread id ${issueCredentialMessage.threadId}`,
         { problemCode: CredentialProblemReportReason.IssuanceAbandoned }
       )
     }
diff --git a/packages/core/src/modules/proofs/messages/PresentationMessage.ts b/packages/core/src/modules/proofs/messages/PresentationMessage.ts
index 65bd1d3aa2..04f56ac045 100644
--- a/packages/core/src/modules/proofs/messages/PresentationMessage.ts
+++ b/packages/core/src/modules/proofs/messages/PresentationMessage.ts
@@ -5,7 +5,6 @@ import { Equals, IsArray, IsString, ValidateNested, IsOptional, IsInstance } fro
 
 import { AgentMessage } from '../../../agent/AgentMessage'
 import { Attachment } from '../../../decorators/attachment/Attachment'
-import { JsonEncoder } from '../../../utils/JsonEncoder'
 
 export const INDY_PROOF_ATTACHMENT_ID = 'libindy-presentation-0'
 
@@ -60,12 +59,7 @@ export class PresentationMessage extends AgentMessage {
   public get indyProof(): IndyProof | null {
     const attachment = this.presentationAttachments.find((attachment) => attachment.id === INDY_PROOF_ATTACHMENT_ID)
 
-    // Return null if attachment is not found
-    if (!attachment?.data?.base64) {
-      return null
-    }
-
-    const proofJson = JsonEncoder.fromBase64(attachment.data.base64)
+    const proofJson = attachment?.data?.getDataAsJson<IndyProof>() ?? null
 
     return proofJson
   }
diff --git a/packages/core/src/modules/proofs/messages/RequestPresentationMessage.ts b/packages/core/src/modules/proofs/messages/RequestPresentationMessage.ts
index fad50b97cc..585e40b1ac 100644
--- a/packages/core/src/modules/proofs/messages/RequestPresentationMessage.ts
+++ b/packages/core/src/modules/proofs/messages/RequestPresentationMessage.ts
@@ -3,7 +3,6 @@ import { Equals, IsArray, IsString, ValidateNested, IsOptional, IsInstance } fro
 
 import { AgentMessage } from '../../../agent/AgentMessage'
 import { Attachment } from '../../../decorators/attachment/Attachment'
-import { JsonEncoder } from '../../../utils/JsonEncoder'
 import { JsonTransformer } from '../../../utils/JsonTransformer'
 import { ProofRequest } from '../models'
 
@@ -58,14 +57,8 @@ export class RequestPresentationMessage extends AgentMessage {
     const attachment = this.requestPresentationAttachments.find(
       (attachment) => attachment.id === INDY_PROOF_REQUEST_ATTACHMENT_ID
     )
-
-    // Return null if attachment is not found
-    if (!attachment?.data?.base64) {
-      return null
-    }
-
     // Extract proof request from attachment
-    const proofRequestJson = JsonEncoder.fromBase64(attachment.data.base64)
+    const proofRequestJson = attachment?.data?.getDataAsJson<ProofRequest>() ?? null
     const proofRequest = JsonTransformer.fromJSON(proofRequestJson, ProofRequest)
 
     return proofRequest
diff --git a/packages/core/src/modules/proofs/services/ProofService.ts b/packages/core/src/modules/proofs/services/ProofService.ts
index 6f83404667..df131aab10 100644
--- a/packages/core/src/modules/proofs/services/ProofService.ts
+++ b/packages/core/src/modules/proofs/services/ProofService.ts
@@ -354,7 +354,7 @@ export class ProofService {
     // Assert attachment
     if (!proofRequest) {
       throw new PresentationProblemReportError(
-        `Missing required base64 encoded attachment data for presentation request with thread id ${proofRequestMessage.threadId}`,
+        `Missing required base64 or json encoded attachment data for presentation request with thread id ${proofRequestMessage.threadId}`,
         { problemCode: PresentationProblemReportReason.abandoned }
       )
     }
@@ -423,7 +423,7 @@ export class ProofService {
     const indyProofRequest = proofRecord.requestMessage?.indyProofRequest
     if (!indyProofRequest) {
       throw new PresentationProblemReportError(
-        `Missing required base64 encoded attachment data for presentation with thread id ${proofRecord.threadId}`,
+        `Missing required base64 or json encoded attachment data for presentation with thread id ${proofRecord.threadId}`,
         { problemCode: PresentationProblemReportReason.abandoned }
       )
     }
@@ -490,14 +490,14 @@ export class ProofService {
 
     if (!indyProofJson) {
       throw new PresentationProblemReportError(
-        `Missing required base64 encoded attachment data for presentation with thread id ${presentationMessage.threadId}`,
+        `Missing required base64 or json encoded attachment data for presentation with thread id ${presentationMessage.threadId}`,
         { problemCode: PresentationProblemReportReason.abandoned }
       )
     }
 
     if (!indyProofRequest) {
       throw new PresentationProblemReportError(
-        `Missing required base64 encoded attachment data for presentation request with thread id ${presentationMessage.threadId}`,
+        `Missing required base64 or json encoded attachment data for presentation request with thread id ${presentationMessage.threadId}`,
         { problemCode: PresentationProblemReportReason.abandoned }
       )
     }