Email providers
Aster Mail privacy rating
Email service from Aster Communications Inc. in the United States, with servers in Germany. Mail between Aster users is end-to-end encrypted with a hybrid post-quantum key exchange. Free and paid plans, no ads in the service.
Summary
Aster Mail scores 62 out of 100 (grade C) on the email providers criteria. It meets 9 of 20 criteria: transparency report, tells users about requests, TLS configuration, security headers, modern web standards, end-to-end encryption, encrypted mailbox storage, custom domains and email security standards. It partly meets open source, no trackers or telemetry, no ads or data sales, open protocols, sign up without personal data and mail transport security. It does not meet independent audit, IMAP support, POP3 support and Sender Rewriting Scheme. Still needing evidence: ARC sealing. It is based in the United States: Five Eyes member; subject to the US CLOUD Act. Automated tests: SSL Labs grade A+, Mozilla HTTP Observatory grade A+, Internet.nl website score 95% and Internet.nl email score 90%.
Score 62 out of 100. How scoring works
Criteria
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Partial
Open source Weight 3 of 3
Is all the source code needed to run the product public?
The web, desktop and Android apps, Aster Bridge and the aster-crypto library are open source under AGPL-3.0. The server is not.
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Partial
No trackers or telemetry Weight 3 of 3
Are the website and apps free of third-party trackers, with any analytics anonymous and any telemetry off by default?
The website loads no third-party trackers or analytics. Sign-ups from Reddit ads are reported to Reddit, and the apps send error reports without an identifier by default.
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Partial
No ads or data sales Weight 2 of 3
Is the product funded without advertising, ad targeting or selling user data?
Funded by paid plans, with no ads in the service. Sign-ups from Aster's own Reddit ads are reported to Reddit through its Conversions API.
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No
Independent audit Weight 2 of 3
Has an independent security or privacy audit been published within the last three years?
No independent audit is published. The transparency page says an audit is underway.
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Yes
Transparency report Weight 2 of 3
Does the provider regularly publish how many government and legal requests it receives and how it responds?
Publishes counts of legal requests received, accepted, denied and contested, with a signed warrant canary.
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Yes
Tells users about requests Weight 1 of 3
Does the provider promise to tell users about requests for their data, unless a court forbids it?
Users are notified of legal requests when the law does not forbid it.
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Yes
End-to-end encryption Weight 3 of 3
Can mail be end-to-end encrypted so that the provider cannot read message contents?
Mail between Aster users is always end-to-end encrypted, including subject lines. OpenPGP or password-protected mail is available for other recipients.
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Yes
Encrypted mailbox storage Weight 3 of 3
Is stored mail encrypted with a key the provider does not hold?
Stored mail, including mail from other providers, is encrypted to the user's key. Private keys are stored encrypted with a key derived from the password.
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Partial
Open protocols Weight 2 of 3
Can any standard app connect over IMAP, POP3, SMTP, CalDAV or CardDAV, without extra software?
IMAP, POP3 and SMTP need the Aster Bridge app and the Star plan or higher.
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Yes
Custom domains Weight 1 of 3
Can mail be sent and received with your own domain?
One custom domain on the free plan, and more on paid plans.
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Partial
Sign up without personal data Weight 2 of 3
Can an account be created without a phone number or another email address?
No phone number or recovery email is needed for a first account. A recovery email is required to create additional accounts.
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No
Sender Rewriting Scheme Weight 1 of 3
Is the envelope sender rewritten with SRS when mail is forwarded, so forwarded mail keeps passing SPF?
No published documentation on SRS for forwarded mail.
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Unknown
ARC sealing Weight 1 of 3
Does the provider validate and add ARC (RFC 8617) signatures, so authentication results survive forwarding?
Needs evidence. Add it
Automated tests
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Yes
TLS configuration Weight 2 of 3
Does the website pass the Qualys SSL Labs test with a grade of A or better?
Grade A+
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Yes
Security headers Weight 1 of 3
Does the website pass the Mozilla HTTP Observatory test with a grade of A or better?
Grade A+ (135/100+)
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Yes
Modern web standards Weight 1 of 3
Does the website score 90% or higher on the Internet.nl website test?
Score 95%
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Yes
Email security standards Weight 2 of 3
Does the mail domain score 90% or higher on the Internet.nl email test?
Score 90%
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No
IMAP support Weight 2 of 3
Does the IMAP server accept connections over implicit TLS on port 993 and advertise IMAP4rev1 or IMAP4rev2 with IDLE push?
Not offered.
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No
POP3 support Weight 1 of 3
Does the POP3 server accept connections over implicit TLS on port 995 and answer CAPA with UIDL?
Not offered.
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Not tested yet
SMTP submission Weight 2 of 3
Does mail submission work over implicit TLS on port 465 with SMTPUTF8, 8BITMIME, PIPELINING and AUTH?
Could not test: No server found (set a host in the rating file or publish RFC 6186 SRV records)
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Partial
Mail transport security Weight 3 of 3
Does the mail domain enforce encrypted, authenticated delivery with MTA-STS, DANE, DNSSEC, TLS-RPT and an enforced DMARC policy?
Passes: SPF, DMARC reject, TLS-RPT, DNSSEC, DANE all. Missing: MTA-STS invalid.
Email standards
- Yes: Mail serversMXmx.astermail.org
- Yes: RFC 7208 sender policySPFpublished
- Yes: RFC 7489. Quarantine or reject counts as enforcedDMARCp=reject
- No: RFC 8461 strict transport securityMTA-STSinvalid
- Yes: RFC 8460 TLS failure reportsTLS-RPTpublished
- Yes: RFC 4033 signed DNSDNSSECsigned and validated
- Yes: RFC 7672 TLSA records on MX hostsDANEall
- Yes: Brand logo record (not scored)BIMIpublished
- No: RFC 6186 and RFC 8314 service records (not scored)SRVnone
IMAP
Not offered.
POP3
Not offered.
SMTP submission
Could not test: No server found (set a host in the rating file or publish RFC 6186 SRV records)
Capabilities are what each server advertises before login. How these tests work