The key, message, and signature come from:
http://csrc.nist.gov/groups/STM/cavp/documents/dss/186-3ecdsatestvectors.zip (SigVer.rsp)

The algorithm DER was synthesized to match, and the signature (provided as an r
and s tuple) was encoded into a Ecdsa-Sig-Value and then a BIT STRING.

It uses ECDSA verification, using curve prime256v1 and SHA-512


$ openssl asn1parse -i < [PUBLIC KEY]
    0:d=0  hl=2 l=  89 cons: SEQUENCE          
    2:d=1  hl=2 l=  19 cons:  SEQUENCE          
    4:d=2  hl=2 l=   7 prim:   OBJECT            :id-ecPublicKey
   13:d=2  hl=2 l=   8 prim:   OBJECT            :prime256v1
   23:d=1  hl=2 l=  66 prim:  BIT STRING        
-----BEGIN PUBLIC KEY-----
MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEnLDPaTA9r8dh1ORoe07PA55tNKuWSvgIENjVWKS
o1vctUSM6F4iSCobuCKGWLHnvoxf7eHnil9rSFG25lfoceA==
-----END PUBLIC KEY-----

$ openssl asn1parse -i < [ALGORITHM]
    0:d=0  hl=2 l=  10 cons: SEQUENCE          
    2:d=1  hl=2 l=   8 prim:  OBJECT            :ecdsa-with-SHA512
-----BEGIN ALGORITHM-----
MAoGCCqGSM49BAME
-----END ALGORITHM-----

-----BEGIN DATA-----
bikyFTMBpO72gOZCiSmtrpiMEI1mijH/VdBImUfXX/gaRr+J6E1kAfAjvm6HaI+814TXhcqEZzV
SSstS0ARSyEBApHnnzDMJNkQdk7vnIqlDKm4dsRK1yUA7ECcssTR/1hnUY/ep0iOtdv3gbYpog1
APuEMjWr/5jiQb37VTjD4=
-----END DATA-----

$ openssl asn1parse -i < [SIGNATURE]
    0:d=0  hl=2 l=  71 prim: BIT STRING        
-----BEGIN SIGNATURE-----
A0cAMEQCIEufkeQoUocmGh0ckjz2Gc1SwXXP5/G+YKUljGEDSLo9AiAoxF+QHXHEGymGOOwNaoX
X/LDDO7/sWpyBCEa2OSiahA==
-----END SIGNATURE-----