This is a synthesized Certificate, where the signature algorithm is an INTEGER rather than a SEQUENCE. $ openssl asn1parse -i < [CERTIFICATE] 0:d=0 hl=2 l= 12 cons: SEQUENCE 2:d=1 hl=2 l= 2 cons: SEQUENCE 4:d=2 hl=2 l= 0 prim: NULL 6:d=1 hl=2 l= 2 prim: INTEGER :0500 10:d=1 hl=2 l= 2 prim: BIT STRING -----BEGIN CERTIFICATE----- MAwwAgUAAgIFAAMCAKs= -----END CERTIFICATE-----