DKIM (DomainKeys Identified Mail)

Introduction

DomainKeys Identified Mail (DKIM) is an email authentication method designed to detect forged sender addresses in emails (email spoofing), a technique often used in phishing and email spam. source

Description

DKIM is a more advanced method than SPF (Sender Policy Framework) for combating email spoofing. It uses Public-Key cryptography to digitally sign each email. A mail server generates a keypair and the public key is then added as a DNS record for that domain. Using the private key the mail server affixes a digital signature to each email. The receiving Mail Transfer Agent (MTA) can then lookup the public key using the DNS record matching the sending domain and validate the signature.

Example

Domain	Type	Value
mail._domainkey	TXT	v=DKIM1; h=sha256; k=rsa; p=MIICIjANBgkqhkiG9w0BAQEFAAOCAg8AMIICCgKCAgEA0SF9l7b0bMcB3ptHM6LbV+rZ/rz1SmHyNCKzBrB6rs433avNHFO4bbs//NG9ZvrCqeElC4NlXPO0VLI8Vbor9dA7HVcSct5aH9/qRWUMfE3LEH9cBVytVAm3/ICgHN6qhWKbnPxK//zh5tmzgdcTKuWyiqhLSECbX63q3gWyuXYMJKqr/BzEq0fzLJymHCfaWkG3MI02pRp68HgpVcpvx2G/t3BKz50BrZVOlSSE9Gi7wbb9jrdeGLwBYIBD4LR+QkVIr8z+ptCMfg+XOfJzLDsBNBUHnBFT/7N3/Ub9BNxsLBltZX3mAWNQQY/n31SC7ik9qs3t6lt22er1jo3WZqjWxBM4xseynUvfn4Lgcp+XQAZCWRQIHr2hwrX4KO1mK/vvvb/dS+NmCNXmWkDvzerVPBCXdfBn+1nbnAsv0vzBuf2yELfRkAIuQRE/PRpeETXAjoayYsVePpOtJn5co0tuiOwbjUf+9hkNO1a3aN/jrK41BDJrGoNjvul3kWZX1Tz42lCQ168x6tuR5ImB5jJFIgGJz+dC5wY8Gmt4hCf1GPW6g7RJpaGUXTEFAEAE0iECsMjg2/Tm2Sb/H4phN/F2AnF4bkju548Yg73X37tVCkLejMgwH7TTgyQvZ/nXhsE4q31YrNZSNnWZMV+9z/yJyQvVmTXsOoDAIfkqxfcCAwEAAQ==