diff --git a/packages/artifact/__tests__/crc64.test.ts b/packages/artifact/__tests__/crc64.test.ts
index e27a4346..f5b504fa 100644
--- a/packages/artifact/__tests__/crc64.test.ts
+++ b/packages/artifact/__tests__/crc64.test.ts
@@ -1,23 +1,36 @@
-import CRC64 from '../src/internal/crc64'
+import CRC64, {CRC64DigestEncoding} from '../src/internal/crc64'
 
 const fixtures = {
   data:
     '🚀 👉😎👉 Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.\nUt enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.\nDuis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur.\nExcepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.\n',
-  expected: '846CE4ADAD6223ED'
+  expected: {
+    hex: '846CE4ADAD6223ED',
+    base64: '7SNira3kbIQ=',
+    buffer: Buffer.from([0xed, 0x23, 0x62, 0xad, 0xad, 0xe4, 0x6c, 0x84])
+  }
+}
+
+function assertEncodings(crc: CRC64): void {
+  const encodings = Object.keys(fixtures.expected) as CRC64DigestEncoding[]
+  for (const encoding of encodings) {
+    expect(crc.digest(encoding)).toEqual(fixtures.expected[encoding])
+  }
 }
 
 describe('@actions/artifact/src/internal/crc64', () => {
   it('CRC64 from string', async () => {
     const crc = new CRC64()
     crc.update(fixtures.data)
-    expect(crc.digest()).toEqual(fixtures.expected)
+
+    assertEncodings(crc)
   })
 
   it('CRC64 from buffer', async () => {
     const crc = new CRC64()
     const buf = Buffer.from(fixtures.data)
     crc.update(buf)
-    expect(crc.digest()).toEqual(fixtures.expected)
+
+    assertEncodings(crc)
   })
 
   it('CRC64 from split data', async () => {
@@ -26,7 +39,8 @@ describe('@actions/artifact/src/internal/crc64', () => {
     for (const split of splits) {
       crc.update(`${split}\n`)
     }
-    expect(crc.digest()).toEqual(fixtures.expected)
+
+    assertEncodings(crc)
   })
 
   it('flips 64 bits', async () => {
diff --git a/packages/artifact/__tests__/util.test.ts b/packages/artifact/__tests__/util.test.ts
index 938df3bb..4d043844 100644
--- a/packages/artifact/__tests__/util.test.ts
+++ b/packages/artifact/__tests__/util.test.ts
@@ -75,7 +75,10 @@ describe('Utils', () => {
     const size = 24
     const uncompressedLength = 100
     const range = 'bytes 0-199/200'
-    const digest = 'FFFCD6894DC82C6D'
+    const digest = {
+      crc64: 'bSzITYnW/P8=',
+      md5: 'Xiv1fT9AxLbfadrxk2y3ZvgyN0tPwCWafL/wbi9w8mk='
+    }
     const headers = utils.getUploadHeaders(
       contentType,
       true,
@@ -85,7 +88,7 @@ describe('Utils', () => {
       range,
       digest
     )
-    expect(Object.keys(headers).length).toEqual(9)
+    expect(Object.keys(headers).length).toEqual(10)
     expect(headers['Accept']).toEqual(
       `application/json;api-version=${utils.getApiVersion()}`
     )
@@ -96,7 +99,8 @@ describe('Utils', () => {
     expect(headers['x-tfs-filelength']).toEqual(uncompressedLength)
     expect(headers['Content-Length']).toEqual(size)
     expect(headers['Content-Range']).toEqual(range)
-    expect(headers['x-actions-result-crc64']).toEqual(digest)
+    expect(headers['x-actions-results-crc64']).toEqual(digest.crc64)
+    expect(headers['x-actions-results-md5']).toEqual(digest.md5)
   })
 
   it('Test constructing upload headers with only required parameter', () => {
@@ -229,6 +233,7 @@ describe('Utils', () => {
     const stream = Readable.from(data)
     const digest = await utils.digestForStream(stream)
 
-    expect(digest).toBe('FFFCD6894DC82C6D')
+    expect(digest.crc64).toBe('bSzITYnW/P8=')
+    expect(digest.md5).toBe('Xiv1fT9AxLbfadrxk2y3ZvgyN0tPwCWafL/wbi9w8mk=')
   })
 })
diff --git a/packages/artifact/src/internal/crc64.ts b/packages/artifact/src/internal/crc64.ts
index 381e27ab..452a8286 100644
--- a/packages/artifact/src/internal/crc64.ts
+++ b/packages/artifact/src/internal/crc64.ts
@@ -269,6 +269,8 @@ const PREGEN_POLY_TABLE = [
   BigInt('0x2ADA5047EFEC8728')
 ]
 
+export type CRC64DigestEncoding = 'hex' | 'base64' | 'buffer'
+
 class CRC64 {
   private _crc: bigint
 
@@ -288,8 +290,23 @@ class CRC64 {
     this._crc = CRC64.flip64Bits(crc)
   }
 
-  digest(): string {
-    return this._crc.toString(16).toUpperCase()
+  digest(encoding?: CRC64DigestEncoding): string | Buffer {
+    switch (encoding) {
+      case 'hex':
+        return this._crc.toString(16).toUpperCase()
+      case 'base64':
+        return this.toBuffer().toString('base64')
+      default:
+        return this.toBuffer()
+    }
+  }
+
+  private toBuffer(): Buffer {
+    return Buffer.from(
+      [0, 8, 16, 24, 32, 40, 48, 56].map(s =>
+        Number((this._crc >> BigInt(s)) & BigInt(0xff))
+      )
+    )
   }
 
   static flip64Bits(n: bigint): bigint {
diff --git a/packages/artifact/src/internal/utils.ts b/packages/artifact/src/internal/utils.ts
index 3fa2923e..94217a5c 100644
--- a/packages/artifact/src/internal/utils.ts
+++ b/packages/artifact/src/internal/utils.ts
@@ -1,3 +1,4 @@
+import crypto from 'crypto'
 import {promises as fs} from 'fs'
 import {IncomingHttpHeaders} from 'http'
 import {debug, info, warning} from '@actions/core'
@@ -182,7 +183,7 @@ export function getUploadHeaders(
   uncompressedLength?: number,
   contentLength?: number,
   contentRange?: string,
-  digest?: string
+  digest?: StreamDigest
 ): IHeaders {
   const requestOptions: IHeaders = {}
   requestOptions['Accept'] = `application/json;api-version=${getApiVersion()}`
@@ -205,7 +206,8 @@ export function getUploadHeaders(
     requestOptions['Content-Range'] = contentRange
   }
   if (digest) {
-    requestOptions['x-actions-result-crc64'] = digest
+    requestOptions['x-actions-results-crc64'] = digest.crc64
+    requestOptions['x-actions-results-md5'] = digest.md5
   }
 
   return requestOptions
@@ -297,13 +299,28 @@ export async function sleep(milliseconds: number): Promise<void> {
   return new Promise(resolve => setTimeout(resolve, milliseconds))
 }
 
+export interface StreamDigest {
+  crc64: string
+  md5: string
+}
+
 export async function digestForStream(
   stream: NodeJS.ReadableStream
-): Promise<string> {
+): Promise<StreamDigest> {
   return new Promise((resolve, reject) => {
-    const hasher = new CRC64()
-    stream.on('data', data => hasher.update(data))
-    stream.on('end', () => resolve(hasher.digest()))
-    stream.on('error', reject)
+    const crc64 = new CRC64()
+    const md5 = crypto.createHash('sha256')
+    stream
+      .on('data', data => {
+        crc64.update(data)
+        md5.update(data)
+      })
+      .on('end', () =>
+        resolve({
+          crc64: crc64.digest('base64') as string,
+          md5: md5.digest('base64')
+        })
+      )
+      .on('error', reject)
   })
 }