PEM Decoder — Decode PEM Certificates, Keys & CSRs Free Online
Decode any PEM-encoded cryptographic object — certificates, CSRs, private keys, and public keys.
Jump to tool ↓Frequently Asked Questions
What Is PEM Format?
PEM (Privacy Enhanced Mail) is the de facto standard encoding format for cryptographic data in the Unix/Linux world. Despite the name's origins in email security, PEM is used for SSL certificates, private keys, CSRs, certificate chains, and CRLs. A PEM file is simply a Base64-encoded DER binary wrapped in ASCII header/footer markers.
PEM files can contain multiple blocks concatenated together. A typical Nginx configuration requires a "fullchain" PEM that includes the server certificate followed by intermediate CA certificates. Pasting such a file here will detect and display all blocks.
Different PEM block types require different handling. -----BEGIN CERTIFICATE----- blocks are X.509 certificates. -----BEGIN PRIVATE KEY----- (PKCS#8) and -----BEGIN RSA PRIVATE KEY-----(PKCS#1) are private key formats — this tool identifies them but does not display key material. -----BEGIN CERTIFICATE REQUEST----- is a CSR.
Standards & References
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