AWS Glossary
DKIM
DomainKeys Identified Mail — cryptographic email signatures that prove a domain authorized the message; SES supports Easy DKIM and BYODKIM.
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Summary
DomainKeys Identified Mail — cryptographic email signatures that prove a domain authorized the message; SES supports Easy DKIM and BYODKIM.
Key Facts
- •DomainKeys Identified Mail — cryptographic email signatures that prove a domain authorized the message; SES supports Easy DKIM and BYODKIM
Entity Definitions
- SES
- SES is an AWS service relevant to dkim.
- Amazon SES
- Amazon SES is an AWS service relevant to dkim.
- compliance
- compliance is a cloud computing concept relevant to dkim.
Related Content
- AWS SES— Related service
- AWS SES MIGRATION— Related service
Definition
DKIM (DomainKeys Identified Mail) attaches a cryptographic signature to outbound messages. Receivers look up the public key in DNS (selector._domainkey.example.com) and verify that headers/body were authorized by the signing domain. For DMARC, the DKIM signing domain must align with the visible From domain (organizational domain match under relaxed alignment).
When to use it
- All Amazon SES production sending (Easy DKIM is the default path)
- Multi-ESP setups where you bring your own key (BYODKIM) for consistent selectors across vendors
- Bulk-sender compliance (Google, Yahoo, Microsoft) requiring authenticated, aligned mail
When not to use it
- Signing with a third-party ESP domain that does not align to your From domain if you need DMARC pass
- Rotating keys without dual-publishing DNS long enough for in-flight mail
Tips
- Prefer 2048-bit keys where supported (SES Easy DKIM supports them)
- Keep selector DNS CNAMEs (Easy DKIM) or TXT public keys (BYODKIM) under change control
- Verify alignment on live messages via
Authentication-Resultsheaders, not console checkmarks alone
Gotchas
Serious
- Body/header modifications by intermediate relays that break signatures
- From domain
marketing.brand.comsigned asesp-mail.comwithout alignment → DMARC fail
Regular
- Leaving old selectors published forever after rotation (harmless but noisy)
Related FactualMinds content
Related Services
Amazon SES Email Deliverability Consulting | FactualMinds
Amazon SES email consulting from an AWS Select Tier Partner. SPF/DKIM/DMARC setup, inbox placement optimization, sender reputation, and scalable email infrastructure.
SES Migration & Email Delivery Services | FactualMinds
SES migration consulting — move from SendGrid, Mailgun, Postmark, or SparkPost to Amazon SES. Deliverability, SPF/DKIM/DMARC, monitoring, compliance.
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