# Supported protocols and ciphers between viewers and CloudFront
<a name="secure-connections-supported-viewer-protocols-ciphers"></a>

When you [require HTTPS between viewers and your CloudFront distribution](DownloadDistValuesCacheBehavior.md#DownloadDistValuesViewerProtocolPolicy), you must choose a [security policy](DownloadDistValuesGeneral.md#DownloadDistValues-security-policy), which determines the following settings:
+ The minimum SSL/TLS protocol that CloudFront uses to communicate with viewers.
+ The ciphers that CloudFront can use to encrypt the communication with viewers.

To choose a security policy, specify the applicable value for [Security policy (minimum SSL/TLS version)](DownloadDistValuesGeneral.md#DownloadDistValues-security-policy). The following table lists the protocols and ciphers that CloudFront can use for each security policy.

A viewer must support at least one of the supported ciphers to establish an HTTPS connection with CloudFront. CloudFront chooses a cipher in the listed order from among the ciphers that the viewer supports. See also [OpenSSL, s2n, and RFC cipher names](#secure-connections-openssl-rfc-cipher-names).


|  | Security policy |  | SSLv3 | TLSv1 | TLSv1\$12016 | TLSv1.1\$12016 | TLSv1.2\$12018 | TLSv1.2\$12019 | TLSv1.2\$12021 | TLSv1.2\$12025 | TLSv1.3\$12025 | 
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | 
| Supported SSL/TLS protocols | 
| TLSv1.3 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | 
| TLSv1.2 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ |  | 
| TLSv1.1 | ♦ | ♦ | ♦ | ♦ |  |  |  |  |  | 
| TLSv1 | ♦ | ♦ | ♦ |  |  |  |  |  |  | 
| SSLv3 | ♦ |  |  |  |  |  |  |  |  | 
| Supported TLSv1.3 ciphers | 
| TLS\$1AES\$1128\$1GCM\$1SHA256 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | 
| TLS\$1AES\$1256\$1GCM\$1SHA384 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | 
| TLS\$1CHACHA20\$1POLY1305\$1SHA256 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ |  | ♦ | 
| Supported ECDSA ciphers | 
| ECDHE-ECDSA-AES128-GCM-SHA256 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ |  | 
| ECDHE-ECDSA-AES128-SHA256 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ |  |  |  | 
| ECDHE-ECDSA-AES128-SHA | ♦ | ♦ | ♦ | ♦ |  |  |  |  |  | 
| ECDHE-ECDSA-AES256-GCM-SHA384 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ |  | 
| ECDHE-ECDSA-CHACHA20-POLY1305 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ |  |  | 
| ECDHE-ECDSA-AES256-SHA384 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ |  |  |  | 
| ECDHE-ECDSA-AES256-SHA | ♦ | ♦ | ♦ | ♦ |  |  |  |  |  | 
| Supported RSA ciphers | 
| ECDHE-RSA-AES128-GCM-SHA256 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ |  | 
| ECDHE-RSA-AES128-SHA256 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ |  |  |  | 
| ECDHE-RSA-AES128-SHA | ♦ | ♦ | ♦ | ♦ |  |  |  |  |  | 
| ECDHE-RSA-AES256-GCM-SHA384 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ |  | 
| ECDHE-RSA-CHACHA20-POLY1305 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ |  |  | 
| ECDHE-RSA-AES256-SHA384 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ |  |  |  | 
| ECDHE-RSA-AES256-SHA | ♦ | ♦ | ♦ | ♦ |  |  |  |  |  | 
| AES128-GCM-SHA256 | ♦ | ♦ | ♦ | ♦ | ♦ |  |  |  |  | 
| AES256-GCM-SHA384 | ♦ | ♦ | ♦ | ♦ | ♦ |  |  |  |  | 
| AES128-SHA256 | ♦ | ♦ | ♦ | ♦ | ♦ |  |  |  |  | 
| AES256-SHA | ♦ | ♦ | ♦ | ♦ |  |  |  |  |  | 
| AES128-SHA | ♦ | ♦ | ♦ | ♦ |  |  |  |  |  | 
| DES-CBC3-SHA | ♦ | ♦ |  |  |  |  |  |  |  | 
| RC4-MD5 | ♦ |  |  |  |  |  |  |  |  | 

## OpenSSL, s2n, and RFC cipher names
<a name="secure-connections-openssl-rfc-cipher-names"></a>

OpenSSL and [s2n](https://github.com/awslabs/s2n) use different names for ciphers than the TLS standards use ([RFC 2246](https://tools.ietf.org/html/rfc2246), [RFC 4346](https://tools.ietf.org/html/rfc4346), [RFC 5246](https://tools.ietf.org/html/rfc5246), and [RFC 8446](https://tools.ietf.org/html/rfc8446)). The following table maps the OpenSSL and s2n names to the RFC name for each cipher.

CloudFront supports both classical and quantum-safe key exchanges. For classical key exchanges using elliptic curves, CloudFront supports the following:
+ `prime256v1`
+ `X25519`
+ `secp384r1`

For quantum-safe key exchanges, CloudFront supports the following:
+ `X25519MLKEM768`
+ `SecP256r1MLKEM768`
**Note**  
Quantum-safe key exchanges are only supported with TLS 1.3. TLS 1.2 and earlier versions do not support quantum-safe key exchanges.

  For more information, see the following topics:
  + [Post-Quantum Cryptography](https://aws.amazon.com/security/post-quantum-cryptography/)
  + [Cryptography algorithms and AWS services](https://docs.aws.amazon.com/prescriptive-guidance/latest/encryption-best-practices/aws-cryptography-services.html#algorithms)
  + [Hybrid key exchange in TLS 1.3](https://datatracker.ietf.org/doc/draft-ietf-tls-hybrid-design/)

For more information about certificate requirements for CloudFront, see [Requirements for using SSL/TLS certificates with CloudFront](cnames-and-https-requirements.md).


| OpenSSL and s2n cipher name | RFC cipher name | 
| --- | --- | 
| Supported TLSv1.3 ciphers | 
| TLS\$1AES\$1128\$1GCM\$1SHA256 | TLS\$1AES\$1128\$1GCM\$1SHA256 | 
| TLS\$1AES\$1256\$1GCM\$1SHA384 | TLS\$1AES\$1256\$1GCM\$1SHA384 | 
| TLS\$1CHACHA20\$1POLY1305\$1SHA256 | TLS\$1CHACHA20\$1POLY1305\$1SHA256 | 
| Supported ECDSA ciphers | 
| ECDHE-ECDSA-AES128-GCM-SHA256 | TLS\$1ECDHE\$1ECDSA\$1WITH\$1AES\$1128\$1GCM\$1SHA256 | 
| ECDHE-ECDSA-AES128-SHA256 | TLS\$1ECDHE\$1ECDSA\$1WITH\$1AES\$1128\$1CBC\$1SHA256 | 
| ECDHE-ECDSA-AES128-SHA | TLS\$1ECDHE\$1ECDSA\$1WITH\$1AES\$1128\$1CBC\$1SHA | 
| ECDHE-ECDSA-AES256-GCM-SHA384 | TLS\$1ECDHE\$1ECDSA\$1WITH\$1AES\$1256\$1GCM\$1SHA384 | 
| ECDHE-ECDSA-CHACHA20-POLY1305 | TLS\$1ECDHE\$1ECDSA\$1WITH\$1CHACHA20\$1POLY1305\$1SHA256 | 
| ECDHE-ECDSA-AES256-SHA384 | TLS\$1ECDHE\$1ECDSA\$1WITH\$1AES\$1256\$1CBC\$1SHA384 | 
| ECDHE-ECDSA-AES256-SHA | TLS\$1ECDHE\$1ECDSA\$1WITH\$1AES\$1256\$1CBC\$1SHA | 
| Supported RSA ciphers | 
| ECDHE-RSA-AES128-GCM-SHA256 | TLS\$1ECDHE\$1RSA\$1WITH\$1AES\$1128\$1GCM\$1SHA256 | 
| ECDHE-RSA-AES128-SHA256 | TLS\$1ECDHE\$1RSA\$1WITH\$1AES\$1128\$1CBC\$1SHA256  | 
| ECDHE-RSA-AES128-SHA | TLS\$1ECDHE\$1RSA\$1WITH\$1AES\$1128\$1CBC\$1SHA | 
| ECDHE-RSA-AES256-GCM-SHA384 | TLS\$1ECDHE\$1RSA\$1WITH\$1AES\$1256\$1GCM\$1SHA384  | 
| ECDHE-RSA-CHACHA20-POLY1305 | TLS\$1ECDHE\$1RSA\$1WITH\$1CHACHA20\$1POLY1305\$1SHA256 | 
| ECDHE-RSA-AES256-SHA384 | TLS\$1ECDHE\$1RSA\$1WITH\$1AES\$1256\$1CBC\$1SHA384  | 
| ECDHE-RSA-AES256-SHA | TLS\$1ECDHE\$1RSA\$1WITH\$1AES\$1256\$1CBC\$1SHA | 
| AES128-GCM-SHA256 | TLS\$1RSA\$1WITH\$1AES\$1128\$1GCM\$1SHA256 | 
| AES256-GCM-SHA384 | TLS\$1RSA\$1WITH\$1AES\$1256\$1GCM\$1SHA384 | 
| AES128-SHA256 | TLS\$1RSA\$1WITH\$1AES\$1128\$1CBC\$1SHA256 | 
| AES256-SHA | TLS\$1RSA\$1WITH\$1AES\$1256\$1CBC\$1SHA | 
| AES128-SHA | TLS\$1RSA\$1WITH\$1AES\$1128\$1CBC\$1SHA | 
| DES-CBC3-SHA  | TLS\$1RSA\$1WITH\$13DES\$1EDE\$1CBC\$1SHA  | 
| RC4-MD5 | TLS\$1RSA\$1WITH\$1RC4\$1128\$1MD5 | 

## Supported signature schemes between viewers and CloudFront
<a name="secure-connections-viewer-signature-schemes"></a>

CloudFront supports the following signature schemes for connections between viewers and CloudFront.


|  | Security policy | Signature schemes | SSLv3 | TLSv1 | TLSv1\$12016 | TLSv1.1\$12016 | TLSv1.2\$12018 | TLSv1.2\$12019 |  TLSv1.2\$12021 | TLSv1.2\$12025 | TLSv1.3\$12025 | 
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | 
| TLS\$1SIGNATURE\$1SCHEME\$1RSA\$1PSS\$1PSS\$1SHA256 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | 
| TLS\$1SIGNATURE\$1SCHEME\$1RSA\$1PSS\$1PSS\$1SHA384 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | 
| TLS\$1SIGNATURE\$1SCHEME\$1RSA\$1PSS\$1PSS\$1SHA512 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | 
| TLS\$1SIGNATURE\$1SCHEME\$1RSA\$1PSS\$1RSAE\$1SHA256 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | 
| TLS\$1SIGNATURE\$1SCHEME\$1RSA\$1PSS\$1RSAE\$1SHA384 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | 
| TLS\$1SIGNATURE\$1SCHEME\$1RSA\$1PSS\$1RSAE\$1SHA512 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | 
| TLS\$1SIGNATURE\$1SCHEME\$1RSA\$1PKCS1\$1SHA256 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | 
| TLS\$1SIGNATURE\$1SCHEME\$1RSA\$1PKCS1\$1SHA384 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | 
| TLS\$1SIGNATURE\$1SCHEME\$1RSA\$1PKCS1\$1SHA512 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | 
| TLS\$1SIGNATURE\$1SCHEME\$1RSA\$1PKCS1\$1SHA224 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ |  |  | 
| TLS\$1SIGNATURE\$1SCHEME\$1ECDSA\$1SHA256 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | 
| TLS\$1SIGNATURE\$1SCHEME\$1ECDSA\$1SHA384 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | 
| TLS\$1SIGNATURE\$1SCHEME\$1ECDSA\$1SHA512 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | 
| TLS\$1SIGNATURE\$1SCHEME\$1ECDSA\$1SHA224 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ |  |  | 
| TLS\$1SIGNATURE\$1SCHEME\$1ECDSA\$1SECP256R1\$1SHA256 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | 
| TLS\$1SIGNATURE\$1SCHEME\$1ECDSA\$1SECP384R1\$1SHA384 | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | ♦ | 
| TLS\$1SIGNATURE\$1SCHEME\$1RSA\$1PKCS1\$1SHA1 | ♦ | ♦ | ♦ | ♦ |  |  |  |  |  | 
| TLS\$1SIGNATURE\$1SCHEME\$1ECDSA\$1SHA1 | ♦ | ♦ | ♦ | ♦ |  |  |  |  |  |